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5631 articles

A1019 – Crystallization kinetics of magnetic glass-ceramics prepared by the processing of waste materials

The objective of the present investigation was to study the feasibility of conversion of an intimate mixture of blast furnace slag and blast furnace flue dust generated by a single industrial company into magnetic glass-ceramic product. Blast furnace slag (BFS) and blast furnace flue dust (BFD) are generated at a rate of 300,000 and 30,000 tons/year, respectively, from iron and steel factory. The crystallization mechanisms of a composition containing BFS and BFD in a 50/50 proportion were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystallization temperature was found to vary from 900 to 1100°C and two phases appeared in the crystallized samples: pyroxene Ca(Mg, Fe, Al)(Si, Al)2O6 and magnetite/maghemite. Heating rate and particle sizes effects on crystal growth of powdered samples were studied by DTA. The apparent activation energy of crystal growth using the particle size 180-315 µm was determined to be 355 and 329 kJ/mol for the first and second peak, respectively. The presence of sharp and broad crystallization peaks indicate simultaneous surface and internal crystallization mechanism. Good wear resistance and chemical durability particularly in alkaline environment, combine with good hardness and magnetic properties make this glass-ceramic material potentially useful for various industrial applications.
A.A. Francis, Materials Research Bulletin 41 (2006) 1146-1154

A1018 – Segregation study and segregation modeling of Ti in Pb[(Mg1/3Nb2/3)0.60Ti0.40]O3 single crystal grown by Bridgman method

Relaxor ferroelectric 0.60Pb(Mg1/3Nb2/3)O3-0.40PbTiO3 single crystal was synthesized by Bridgman method. The segregation along the length of this crystal was observed by various physico-chemical characterization techniques. First, we note the evolution of the crystalline structure along the length of the as-grown crystals. The tetragonality factor c/a increases from 1.013 to 1.020. This evolution has been correlated with the Ti content determination by flame atomic absorption spectrometry, and it is shown that this is due to the evolution of Ti concentration along the crucible. Furthermore, a continuous increase of the fraction of tetragonal phase with increasing Ti content was observed. Hence, we could compare the experimental data with a standard segregation model and therefore calculate the effective segregation coefficient keff for this composition. This coefficient was found to be equal to 0.849. The variation of the titanium content along the ingot causes an inevitable fluctuation of the dielectric and piezoelectric properties of the single crystal. Due to the increase of Ti concentration, the Curie point was 186°C at the bottom of the ingot and 222°C at the top. The piezoelectric coefficient of oriented and poled <0 0 1> samples varies from 1500 to 250 pC/N.
A. Benayad, G. Sebald, L. Lebrun, B. Guiffard, S. Pruvost, D. Guyomar, L. Beylat, Materials Research Bulletin 41 (2006) 1069-1076

A1017 – Sol-gel processing of Sr0.5Sm0.5CoO3 film

Strontium-doped samarium cobaltite (Sm0.5Sr0.5CoO3, SSC) has attracted increasing attention as cathode material for intermediatetemperature solid oxide fuel cells (IT-SOFCs) due to its mixed-conduction characteristics and relatively high ionic conductivity. In this paper, sol-gel-derived SSC films were deposited on yttria stabilized zirconia (YSZ) substrates from an alkoxide solution of strontium isopropoxide, samarium isopropoxide and cobalt isopropoxide. The alkoxide solution was chelated with 2-ethylacetoacetate (CH3COCH2COOC2H5), and the effect of polyethylene glycol (PEG) addition on the crystallization behavior and microstructure evolution of SSC films was investigated. XRD, TGA and SEM measurements indicated that single-perovskite phase SSC films were formed when the films were heated at 700°C, and PEG could significantly refine the crystalline size of the SSC film from around 100-50 nm.
Z. Tang, Y. Xie, H. Hawthorne, D. Ghosh, Journal of Power Sources 157 (2006) 385-388

A1021 – La2Zr2O7 films on Cu-Ni alloy by chemical solution deposition process

Films of La2Zr2O7 (=LZO) have been formed by chemical solution deposition technique (CSD) on new bi-axially textured Cu-Ni alloy tapes based on rolled constantan (Cu55Ni45) Rabits. The precursor used was acetylacetonates treated in propionic acid (0.1-0.87 mol/l) and then deposited by spin-coating. The LZO film starts to crystallize above 850°C, the film nucleates bi-axially textured on the substrate (with unit cell axis rotated 45° from those of the substrate). The top part of the film is not textured even after long annealing time at 1100°C, but the interfacial part is bi-axially textured. Thus, synthesis of bi-axially textured films on Cu55Ni45 Rabits seems possible but more works are needed to optimize its properties.
Z.M. Yu, P. Odier, L. Ortega, L. Zhou, P.X. Zhang, A. Girard, Materials Science and Engineering B 130 (2006) 126-131

A1020 – Soft chemistry synthesis, structure and electrochemical characterization of iron phosphates Fe(H2PO4)3 and Fe(PO3)3

The iron phosphate, Fe(H2PO4)3, was synthesized through a precipitation route by means of acidic media. As the compound is highly hygroscopic, the structure was solved ab initio by powder X-ray diffraction under nitrogen flow at room temperature and 200°C. This phase is antiferromagnetic below 30 K. It converts into Fe(PO3)3 at 550°C, after dehydration. Electrochemical characterizations, performed on the last compound, show irreversible decomposition into metallic iron.
R. Baies, V. Pralong, V. Caignaert, B. Raveau, Materials Research Bulletin 41 (2006) 1170-1177

A1022 – Particle surface properties of stainless steel-coated tungsten carbide powders

Tungsten carbide powders sputter-deposited with stainless steel were characterized in order to evaluate the surface properties in air and aqueous environments. The scanning electron microscopy with energy dispersive spectroscopy showed that a very high uniformity of the coating distribution on the WC particles was attained by the sputtering technique, enabling a complete surface coverage for low coating contents (>1 wt.%). The DTA-TG thermal analysis in air atmosphere revealed that the coating layers increase the oxidation resistance of WC powders, in spite of the coating porosity. The electrophoretic measurements performed in aqueous solution, for different pH at a constant ionic strength (1 mM KCl), showed that the surface charge until pH~8 is essentially determined by the stainless steel coating, while for higher pH it becomes closer to that of the WC particles. The coating adhesion measured by a scratch test was found to decrease in the basic pH region. These results were discussed in terms of the effect of the short-range repulsion forces between the coating layer and the particle surface in aqueous suspensions.
C.M. Fernandes, A.M.R. Senos, M.T. Vieira, Powder Technology 164 (2006) 124-129

A1024 – Synthesis and characterisation of Fe(IO3)3 nanosized powder

Fe(IO3)3 powders have been produced by co-precipitation of iron nitrate and iodic acid in aqueous solution. X ray diffraction studies show that the crystal structure is satisfactorily described in space group P6 3; the cell parameters and the atomic positions have been ascertained by Rietveld refinements. The nanometric size of the Fe(IO3)3 particles has been estimated from the full width at half maximum of the diffraction peaks and confirmed by atomic force microscopy observations. Although we find colour changes and small weight losses below 400°C, the structure is found stable up to this temperature where it decomposes to form nanosized hematite alpha-Fe2O3 powder. Finally, Fe(IO3)3 nanopowder pellets exhibit second harmonic generation of the fundamental wavelength of a Nd:YAG laser.
C. Galez, Y. Mugnier, J. Bouillot, Y. Lambert, R. Le Dantec, Journal of Alloys and Compounds 416 (2006) 261-264

A1023 – About the octopus-like growth mechanism of carbon nanofibers over graphite supported nickel catalyst

Carbon nanofibers (CNFs) with a uniform diameter of ca. 30 nm and a productivity of 50 g/(gNi h) were grown by catalytic decomposition of a C2H6/H2 mixture over a nickel (1 wt%) catalyst supported on graphite microfibers, which constitutes the macroscopic shape of the final C/C composite. The catalyst particle size and dispersion before CNF growth was characterized by high-resolution scanning electron microscopy (SEM). The resulting composite consisting of a weblike network of CNFs covering the starting catalyst was characterized by SEM and transmission electron microscopy to gain more insight into the relationship between the starting nickel catalyst particles and the as-grown CNFs. Apparently, CNF growth proceeds from different mechanisms: a base-growth mechanism, involving especially the large nickel particles; a tip-growth mechanism, involving mostly the smaller nickel particles; and a tip/octopus-growth mechanism (the most common), involving all particles. In all cases, restructuring of the nickel particle from a globular to a more faceted structure seems to be the key step in producing an extremely large quantity of CNFs with yields up to 100 wt%.
C. Pham-Huu, R. Vieira, B. Louis, A. Carvalho, J. Amadou, T. Dintzer, M.J. Ledoux, Journal of Catalysis 240 (2006) 194-202

A1026 – Sulphur-polypyrrole composite positive electrode materials for rechargeable lithium batteries

A novel conducting sulphur-polypyrrole composite material was prepared by the chemical polymerization method with sodium ptoluenesulphonate as the dopant, 4-styrenesulphonic sodium salts as the surfactant, and FeCl3 as the oxidant. The new material was characterized by Raman spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Nanosize polypyrrole particles were uniformly coated onto the surface of the sulphur powder, which significantly improved the electrical conductivity, the capacity and the cycle durability in a lithium cell compared with the bare sulphur electrode.
J. Wang, J. Chen, K. Konstantinov, L. Zhao, S.H. Ng, G.X. Wang, Z.P. Guo, H.K. Liu, Electrochimica Acta 51 (2006) 4634-4638

A1025 – Synthesis, characterization and photocatalytic activity of different metal-doped titania systems

Different titania-based systems doped with diverse transition metals (Ag, Fe, Pd, Pt, Zn and Zr) were synthesized by the sol-gel method. Samples were characterized by a wide range of physical techniques (ICP-MS, N2-isotherms, TGA-DTA, TEM, XRD, FT-Raman and UV-vis spectroscopies). The effect of aging of the gel either under magnetic stirring (ST) or ultrasonic irradiation (US) on the characteristics of the resulting solids was studied. Sonication ensured the obtention of pure anatase nanoparticles and generally led to an increase in surface area. All the solids were tested for gas phase selective photooxidation of 2-propanol. Irrespective of the aging method, doping with Pd, Pt or Ag resulted in an increase in molar conversion as compared to bare-TiO2, whereas the presence of Fe and Zr had a detrimental effect. Those solids for which sonication had the greatest impact on textural and structural characteristics (bare-TiO2 and Zn-containing samples) exhibited the greatest difference in molar conversion. Moreover, high selectivities to acetone were achieved in most of the cases.
J.C. Colmenares, M.A. Aramendia, A. Marinas, J.M. Marinas, F.J. Urbano, Applied Catalysis A: General 306 (2006) 120-127

A1028 – Copper oxide modified large pore ordered mesoporous silicas for ethyl acetate combustion

Copper oxide supported on large pore ordered mesoporous silicas with channel- and cage-like structures are obtained and characterized with N2-physisorption, XRD, XPS and TPR with hydrogen. The state of copper species, their reductive properties and catalytic behaviour in ethyl acetate combustion are significantly influenced by the silicas pore architecture.
T. Tsoncheva, M. Linden, S. Areva, Ch. Minchev, Catalysis Communications 7 (2006) 357-361

A1027 – Formation of low-density carbon materials through thermal degradation of a cork-based composite

S. Reculusa, M. Trinquecoste, L. Dariol, P. Delhaès, Carbon 44 (2006) 1298-1352

A1029 – Thermal behaviour of geopolymers prepared using class F fly ash and elevated temperature curing

This article reports a study of thermal stability of properties upon firing at 800-1200°C of geopolymer materials prepared using class F fly ash and Na and K alkaline activators. Compressive strength and shrinkage measurements, XRD, SEM (BEI), TGA and MIP were utilised in these studies. The materials were prepared at water/binder ratios in a range of 0.09-0.35, using compaction pressures up to 10 MPa and curing temperatures 80 and 100°C. Thermal stability of the studied geopolymer materials was rather low. In the samples prepared using sodium-containing activators rapid deterioration of strength at 800°C was observed, which was connected to a dramatic increase of the average pore size. Initially amorphous structures were replaced by the crystalline Na-feldspars. In materials prepared using fly ash and potassium silicate compressive strength was significantly increased on heating, deterioration of strength started at 1000°C. After firing these materials remained amorphous with reduced average pore size and significantly increased compressive strength. Compaction at 1-10 MPa reduced shrinkage on firing in all materials. Geopolymer materials prepared using class F fly ash and alkaline activators showed high shrinkage as well as large changes in compressive strength with increasing fired temperature in the range of 800-1200°C. Thus the materials were found unsuitable for refractory insulation applications.
T. Bakharev, Cement and Concrete Research 36 (2006) 1134-1147

A1030 – Water – an important parameter for the preparation and proper use of certified reference materials

Property values of powdered certified reference materials (CRMs) are very often related to dry mass. The dry mass is indirectly determined by measuring the moisture content of the sample. The most commonly used methods are the drying oven method and the Karl Fischer titration (KFT). It is well known that these two methods may give different values for the moisture/water content. In this study thermogravimetry was used to simulate the drying oven method and to investigate the reasons of the differences between both moisture/water content determination methods. A mass spectrometer coupled to a thermobalance (TGMS) added further useful information regarding the release of volatile substances and the decomposition of the material during the drying process. The relative humidity of the laboratory may influence the water content of powdered CRMs because of their more or less pronounced tendency to take up water (hygroscopicity). This fact can lead to biased property values. The water adsorption kinetics and the water uptake capacity vary, depending on the constitution of the sample. This was studied analysing several powdered food CRMs and individual constituents thereof. The speed of water uptake and the water uptake capacity were described using an exponential function. The findings have consequences both for the producer and for the user of certified reference materials.
S. Yazgan, A. Bernreuther, F. Ulberth, H-D. Isengard, Food Chemistry 96 (2006) 411-417

A1032 – Thermogravimetric analysis during the decomposition of cotton fabrics in an inert and air environment

The thermal degradation of samples of used cotton fabrics has been investigated using thermogravimetric analysis (TGA) between room temperature and 700°C. Experiments were carried out with about 5 mg of sample in three different atmospheres: helium, 20% oxygen in helium and 10% oxygen in helium. Three different heating rates were used at each atmosphere condition. A kinetic model for the decomposition of used cotton fabrics explaining the behavior of all the runs performed has been proposed and tested. For the pyrolysis of the cotton, the model comprises two parallel reactions. For the combustion process, one competitive reaction was added to each parallel reaction of the pyrolysis model and four combustion reactions of the different solid fractions to obtain volatiles. One single set of parameters can explain all the experiments (pyrolysis, oxidative pyrolysis and combustion) at the three different heating rates used.
J. Molto, R. Font, J.A. Conesa, I. Martin-Gullon, J. Anal. Appl. Pyrolysis 76 (2006) 124-131

A1031 – Pyrolysis characteristics and global kinetics of coconut and cashew nut shells

Coconut and cashew nut shells are two typical biomass wastes abundant in most of the tropical countries. However, despite their enormous potential as energy sources, they are hardly studied and their thermal characteristics are still not well known. In this study, both biomasses are thermally degraded through thermogravimetry and their characteristics such as devolatilisation profiles and kinetics are analyzed, from 250 to 900°C, in an inert atmosphere, at two different heating rates, and compared with wood pellets. The results show that their pyrolysis profiles are different from that of the commonly studied woody biomass. In fact, they present two different peaks instead of the one overlapping peak, for hemicellulose and cellulose. In addition, they present activation energies ranging from that are slightly above the commonly known maximum for biomass. At 10 and 20°C/min the activation energy varied from about 130 to 174 and 180 to 216 kJ/mol, for cashew and coconut shells, respectively.
A.J. Tsamba, W. Yang, W. Blasiak, Fuel Processing Technology 87 (2006) 523-530

A1033 – Fitting TGA data of oil sludge pyrolysis and oxidation by applying a model free approximation of the Arrhenius parameters

Interpreting the thermal pyrolysis data from organic substances using thermogravimetric analysis (TGA) requires assuming certain formal kinetic models to be a priori for parametric fitting. The form of the assumed model limits the accuracy of stimulating the pyrolysis data. This work demonstrates the feasibility of modeling the pyrolyzed sample as a continuous mixture, in which an Arrhenius-type kinetics is applied with activation energy, pre-exponential factor, and reaction order as continuous functions of conversion. Such a data fitting scheme is not used to identify the actual chemical kinetics involved, but rather to describe the complex chemical kinetics in a unified, "model free" manner for engineering applications.
R.M. Wu, D.J. Lee, C.Y. Chang, J.L. Shie, J. Anal. Appl. Pyrolysis 76 (2006) 132-137

A1035 – Thermal decomposition of HfCl4 as a function of its hydration state

The thermogravimetric behavior of HfCl4 powders with different hydration states has been compared. Strongly hydrated powders consist of HfOCl2 . nH2O with n>4. Partially hydrated powders consist of particles with a HfCl4 core and a hydrated outerlayer of HfOCl2 . nH2O with n in the range of 0-8. Hydrated powders decomposed at temperature lower than 200°C whereas the decomposition of partially hydrated powders was completed at a temperature of around 450°C. The observed differences in decomposition temperature is related to the structure of HfOCl2 . nH2O, which is different if n is higher or smaller than 4 and leads to intermediate compounds, which decompose at different temperatures.
E. Barraud, S. Bégin-Colin, G. Le Caër, F. Villieras, O. Barres, Journal of Solid State Chemistry 179 (2006) 1842-1851

A1034 – Synthesis and characterization of ilmenite NiTiO3 and CoTiO3 prepared by a modified Pechini method

Powders of ilmenite structure NiTiO3 and CoTiO3 were prepared by a simple method based on the modified Pechini process. The raw compounds and citric acid (CA) were mixed in ethanol (EA) with the molar ratio Ni(Co)/Ti/CA/EA = 1/1/1/7.5. The DTA curve shows exothermic peaks only around 300-350°C and 600°C, which correspond to the decomposition of the organic compound and direct crystallization of the ilmenite phase. X-ray diffraction patterns indicated that the ilmenite phase was successfully synthesized as the Ni(Co)-Ti precursor calcined above 600-900°C for 3 h, and the activation energies of NiTiO3 and CoTiO3 were calculated to be about 8.84 and 13.23 kJ/mol. TEM bright field images showed that the grain sizes of powders of NiTiO3 and CoTiO3 at 600-900°C were estimated to be about 10-250 and 20-200 nm depending on the nature of the aggregate. The samples of NiTiO3 calcined at 600-800°C have the larger specific surface area of 31.51, 18.78, and 6.01 m2/g, respectively. The UV-Vis diffuse reflectance spectra show the optical band gaps of NiTiO3 and CoTiO3 as 3.02 and 2.43 eV.
Y-J. Lin, Y-H. Chang, W-D. Yang, B-S. Tsai, Journal of Non-Crystalline Solids 352 (2006) 789-794

A1036 – Effect of ZnO-doping on the reaction between Co and Fe oxides

The effects of zinc oxide on the solid-solid interactions between cobalt and ferric oxides have been investigated by DTA-TG, XRD and SEM technologies. The dopant concentration was less than 0.6, and the solids were calcined at a series temperature of 600°C, 740°C, 870°C and 1000°C. Zn2+ began to diffuse into Co3O4 and Fe2O3 at temperature of about 600°C, by which the ionic mobility was enhanced. Therefore, the ZnO doping could decrease the temperature of chemical reactions between cobalt and ferric oxides to produce CoFe2O4. At the temperature of 1000°C, cobalt ferrite with a smaller crystal lattice parameter was obtained by over Co3O4 other than the lager crystal lattice as reported. And Zn-doped CoFe2O4 with the uniform particles was produced.
J-P. Zhou, H-C. He, Y-H. Lin, C-W. Nan, Materials Letters 60 (2006) 1542-1548

A1038 – Removal of some heavy metal ions from aqueous solution by adsorption using poly(ethylene terephthalate)-g-itaconic acid/acrylamide fiber

In this study, a new fibrous adsorbent was prepared by grafting itaconic acid/acrylamide (IA/AAm) comonomers onto poly(ethylene terephthalate) (PET) fibers for removal of Cu(II), Ni(II) and Co(II) metal ions from aqueous solution by using batch adsorption method. Effects of various parameters such as grafting yield, pH, shaking time, initial ion concentration and reaction temperature on the adsorption amount of ions onto reactive fibers were investigated. Moreover, the recyclability and selectivity of the reactive fibers were studied. The results show that the adsorption rate of metal ions followed as given in the order Ni(II) > Co(II) > Cu(II). The adsorption amount of ions increased with grafting yield, shaking time, adsorption temperature and pH of the medium. The maximum adsorption capacities of the reactive fiber for Cu(II), Ni(II) and Co(II) are 7.73, 13.79 and 14.81 mg/g, respectively. It was found that the adsorption isotherm of the ions fitted Langmuir-type isotherm. The activation energies of ions for adsorption were calculated as 17.32, 12.83 and 6.98 kJ/mol for Cu(II), Ni(II) and Co(II) ions, respectively. It was observed that the grafted fibers are stable and regenerable by acid without losing their activity and it is more selective for Cu(II) ions in the mixed solution of Cu-Ni, Cu-Co, and Cu-Ni-Co at pH 4. The grafted fibers and the metal loaded fibers were characterized by FTIR, TGA and SEM.
R. Coskun, C. Soykan, M. Saçak, Reactive & Functional Polymers 66 (2006) 599-608

A1037 – Thermal stability and flammability of silicone polymer composites

Silicone polymer composites filled with mica, glass frit, ferric oxide and/or a combination of these were developed as part of a ceramifiable polymer range for electrical power cables and other high temperature applications. This paper reports on the thermal stability of polymer composites as determined by thermogravimetric techniques, thermal conductivity and heat release rate as measured by cone calorimetry. The effects of fillers on thermal stability and flammability of silicone polymer are investigated. Of the fillers studied, mica and ferric oxide were found to have a stabilising effect on the thermal stability of silicone polymer. Additionally, mica and ferric oxide were found to lower heat release rates during combustion, but only mica was found to increase time to ignition.
L.G. Hanu, G.P. Simon, Y-B. Cheng, Polymer Degradation and Stability 91 (2006) 1373-1379

A1039 – Hydrothermal synthesis, crystal structure and thermal behaviour of the first lanthanide sulfato-squarate, La2(H2O)4(SO4)2(C4O4)

A new three-dimensional lanthanum(III) sulfate squarate, La2(H2O)4(SO4)2(C4O4), has been synthesized hydrothermally with squaric acid at 180°C and its structure has been solved by single-crystal X-ray diffraction methods. A relevant feature of this new material is that it constitutes the first member of a family of hybrids based on this composition. It crystallizes in the monoclinic space group P21/n, with a = 6.5965(1) Å, b = 10.9595(3) Å, c = 9.6633(2) Å, beta = 96.457(1)°, V = 694.17(3) Å3, Z = 2. Its framework is built up from dimers of O-O edged-sharing nine-coordinated LaO7(H2O)2 polyhedra described as monocapped square antiprisms. The linking of the binuclear La species by sulfate groups occurs in planes parallel to (101) and subsequently generates inorganic layers showing cavities. The stacking of them along the a-axis generates tunnels filled with bonded water molecules and squarate moieties. The three-dimensionality is ensured by one sulfate oxygen atom and the C4- cycles. Thus, according to this structural description, the material presents a novel 3D-type structure in the field of the mixed anionic lanthanide compounds. The thermal behavior of La2(H2O)4(SO4)2(C4O4) has been investigated using TG-DTA and X-ray thermodiffractometry showing that this precursor of crystallized lanthanum oxide at 900°C is stable up to 150°C.
H. Akkari, P. Bénard-Rocherullé, H. Mérazig, T. Roisnel, J. Rocherullé, Solid State Sciences 8 (2006) 704-715

A1040 – Spectral and structural study of two acceptor-substituted pyridinium-betaines of squaric acid: Promising chromophores for nonlinear optical applications

Two acceptor-substituted chromophores (3- and 4-benzoylpyridinium-betaines of squaric acid) were characterized by means of thermogravimetric analysis and UV-vis and IR spectra. The experiment is supported by theoretical predictions undertaken at different levels of approximation (MP2 and DFT/B3LYP). The results of the optimized molecular structure are presented and compared with the X-ray diffraction data for both chromophores studied. Generalized atomic polar tensor (GAPT) model was chosen for calculation of atomic charges of studied species. The charge distribution over fragments indicates that strongly polarized systems are present. Harmonic vibrational frequencies of the molecules were evaluated theoretically using B3LYP/6-311G** level. The nonlinear optical efficiency of both chromophores was estimated by molecular parameters such as absorption maxima in various solvents of different polarity, ground state dipole and difference between ground and excited state dipole moments. A static hyperpolarizability for 4-benzoyl chromophore was provided from EOAM experiment for a dioxane solution. Combined with the noncentrosymmertic crystal structure of the same isomer and the exceptional thermal stability of both species, these studies gave evidences for their reliability as nonlinear optical materials.
T. Kolev, B. Stamboliyska, D. Yancheva, Chemical Physics 324 (2006) 489-496

A1041 – Geochemical and micropaleontological characterisation of a Mediterranean sapropel S5: A case study from core BAN89GC09 (south of Crete)

Several geochemical and micropaleontological proxies were studied in a well developed sapropel S5 from a core collected south of Crete to investigate the causes and the mechanisms of its deposition, to reconstruct the paleoenvironmental and paleoceanographical conditions at time of its formation and to detect the roles played by productivity and anoxia. The geochemical proxies are also used to unravel the sediment provenance and therefore to help tracing water circulation patterns and freshwater sources. The multiproxy approach reveals that the sapropel layer has high internal variability and five different depositional phases can be identified, four within the visible sapropel layer. An increase in temperature and the development of a Deep Chlorophyll Maximum characterise the onset of the sapropel (phase 1), with enhanced productivity being favoured by local riverine input, not clearly ascribable to Nile river freshwater discharge, and by the shoaling of the pycnocline/nutricline. Surface water stratification and productivity develop, together with strong seafloor dysoxia/anoxia. Phase 2 is characterised by lower stratification, slightly lower temperature and/or higher seasonal contrast, and still high productivity. Phase 3 records high productivity, high temperature and high stratification, probably more sustained by the Nile input. A sudden partial reoxygenation takes place at the end of this phase, changing the main features of the sapropel. In the fourth phase, productivity starts to decrease, water stratification seems to be partially broken down and sediment oxygenation increases. A transitional phase (phase 5) occurs between the end of the visible sapropel and the normal pelagic post-sapropel sedimentation, where productivity is still high and oxygenation improves compared to the visible sapropel layer. The massive occurrence of Polysphaeridium zoharyi, cyst of a red tide forming dinoflagellate, also characterises this phase. The geochemical proxies indicate that pre-sapropel and post-sapropel sediments are quite different from each other, and the provenance shifts from a more mixed to a more markedly southern origin of sediments.
F. Sangiorgi, E. Dinelli, P. Maffioli, L. Capotondi, S. Giunta, C. Morigi, M.S. Principato, A. Negri, K-C. Emeis, C. Corselli, Palaeogeography, Palaeoclimatology, Palaeoecology 235 (2006) 192-207

A1043 – Opportunity of metallic interconnects for ITSOFC: Reactivity and electrical property

Iron-base alloys (Fe-Cr) are proposed hereafter as materials for interconnect of planar-type intermediate temperature solid oxide fuel cell (ITSOFC); they are an alternative solution instead of the use of ceramic interconnects. These steels form an oxide layer (chromia) which protects the interconnect from the exterior environment, but is an electrical insulator. One solution envisaged in thiswork is the deposition of a reactive element oxide coating, that slows downthe formation of the oxide layer and that increases its electric conductivity. The oxide layer, formed at high temperature on the uncoated alloys, is mainly composed of chromia; it grows in accordance with the parabolic rate law (kp = 1.4 x 10^(-12) g2 cm-4 s-1). On the reactive element oxide-coated alloy, the parabolic rate constant, kp, decreases to 1.3x10^(-13) g2 cm-4 s-1. At 800°C, the area-specific resistance of Fe-30Cr alloys is about 0.03 ohm.cm2 after 24 h in laboratory air under atmospheric pressure. The Y2O3 coating reduces the electrical resistance 10-fold. This indicates that the application of Y2O3 coatings on Fe-30Cr alloy allows to use it as an interconnect for SOFC.
G. Cabouro, G. Caboche, S. Chevalier, P. Piccardo, Journal of Power Sources 156 (2006) 39-44

A1042 – Tailored macro/microstructural properties of colloidal silica nanoparticles via microemulsion preparation

Silica nanoparticles were prepared in water in oil microemulsion media using non-ionic surfactant. The mean of reactants incorporation and microemulsion composition were varied in order to study their influence on the macro/microstructure characteristics of the colloids. In particular, different preparations have been performed involving low or high control of the ammonia-catalyzed tetraethoxysilane (TEOS) hydrolysis and condensation reactions. The particles were characterized by electron microscopy, dynamic light scattering and nitrogen sorption. The results showed that monodisperse mesoporous silica colloids can be obtained by controlling the TEOS hydrolysis prior to its introduction in the microemulsion while a direct alkoxysilane monomer addition in the microemulsion leads to bigger silica nanoparticles with no accessible porosity. The hydrolysis controlled preparation procedure gives silica particles which size variation is dependent on the co-surfactant concentration in the microemulsion rather than the water concentration. However, the water concentration in the microemulsion has to be low since it has a dramatic influence on the particles polydispersity.
I. Abarkan, T. Doussineau, M. Smaïhi, Polyhedron 25 (2006) 1763-1770

A1045 – Wettability of calcite and mica modified by different long-chain fatty acids (C18 acids)

The effect of long-chain fatty acid adsorption on the wetting states of calcite and mica powders is investigated. The selected long-chain fatty acids are saturated or unsaturated aliphatic acids (stearic acid and oleic acid, respectively) and naphthenic acids with saturated or unsaturated aromatic rings (18-cyclohexyloctadecanoic acid and 18-phenoloctadecanoic acid, respectively). The amount of irreversibly adsorbed acid is determined by thermogravimetric analysis. The affinity of water and n-decane for these samples before and after modification is deduced from their adsorption isotherm and microcalorimetry. Thermodynamic analysis of surface pressure and spreading tension are performed based on adsorption isotherms. The enthalpy versus coverage curve for water adsorption and its comparison to liquefaction enthalpy is shown to be a meaningful method for characterizing the wettability of a surface. The naphthenic acid with unsaturated aromatic ring deeply modifies the calcite to an oil-wet state. The mica powder was not as strongly modified as calcite by these acid molecules.
K.A. Rezaei Gomari, R. Denoyel, A.A. Hamouda, Journal of Colloid and Interface Science 297 (2006) 470-479

A1044 – Sonocatalysis in solvent free conditions: An efficient eco-friendly methodology to prepare chalcones using a new type of amino grafted zeolites

The synthesis of chalcones via Claisen-Schmidt condensation between benzaldehyde and acetophenone by sonochemical and thermallyactivated reactions over a new type of zeolite as catalyst is reported. The catalysts were prepared by grafting amino groups on sodium and cesium exchanged X zeolite. In this green, solvent free procedure, chalcones are selectively produced in very high yields (>95%) when cesium exchanged X-NH2 is employed under ultrasound activation
E. Perozo-Rondon, R. M. Martin-Aranda, B. Casal, C.J. Duran-Valle, W.N. Lau, X.F. Zhang, K.L. Yeung, Catalysis Today 114 (2006) 183-187

A1047 – Mechanical properties of short flax fibre bundle/poly(epsilon-caprolactone) composites: Influence of matrix modification and fibre content

Composites were prepared by mixing biodegradable poly(epsilon-caprolactone) thermoplastic (PCL) with short flax fibre bundles. In order to improve fibre/matrix adhesion, poly(epsilon-caprolactone)-g-maleic anhydride copolymer (PCL-g-MA) compatibilizer was prepared in an internal mixer. The grafting reaction of maleic anhydride (MA) onto PCL polymer was carried out in presence of dicumyl peroxide as initiator. Mechanical properties were analysed as a function of compatibilizer concentration and fibre amount. In addition, thermal properties of flax/PCL and flax/PCL-g-MA composites were also examined by thermogravimetric (TG) analysis. Composites fabricated with flax fibre bundles and PCL-g-MA matrix showed the highest tensile and flexural strength. Scanning electron microscopy (SEM) of fractured surfaces confirmed the adhesion improvement between flax fibre bundles and PCL-g-MA matrix. Results obtained by thermogravimetric analysis showed that fibre addition and matrix modification slightly reduced the thermal stability of composites. The correlation between the experimental mechanical properties of short flax fibre bundle reinforced PCL composites with values calculated by various empirical models has also been analysed. For composites based on PCL-g-MA matrix, a good agreement was found between empirical model and experimental values for all fibre contents. However, for composites based on PCL matrix a good agreement only existed until 20 wt% flax fibre content, and beyond this value, experimental strength felt well below predictions.
A. Arbelaiz, B. Fernandez, A. Valea, I. Mondragon, Carbohydrate Polymers 64 (2006) 224-232

A1046 – Uniform Y2O3 coating on multi-component phosphor powders by modified polyol process

We have developed a method to coat the phosphors comprising of multi-component systems to prevent them from aging effect. Y2O3 was selected as a protective material because of its superior ability to resist against mercury adsorption and oxidation and its good UV transparency at the wavelength used for phosphor activation. By dispersing the phosphor particles in the polyol medium that contains the yttrium precursor, heterogeneous nucleation and growth on the particle surface were induced. This allows us to obtain a thick and uniform coating of the phosphors with amorphous Y2O3 sols. The heat-treatment condition for Y2O3 sols was carefully controlled to keep the phosphors from surface oxidation and at the same time to assure the complete crystallization and burn-out of organic impurity by XRD and TG/DTA. The surface morphology of the coated phosphors was examined by SEM as a function of reaction time and temperature and precursor concentration.
D. Kim, S. Jeong, J. Moon, S.H. Cho, Journal of Colloid and Interface Science 297 (2006) 589-594

A1049 – Oxyfunctionalization of n-pentane and n-hexane by oxovanadium complexes supported on carbamated modified silica gel

The bis(maltolato)oxovanadium complexes cis-[VO(OCH3)(ma)2] 1, cis-[VO(OC2H5)(ma)2] 2, [VO(ma)2] 3 and [VO(py)(ma)2] 4 have been anchored to chemically modified silica gel and are shown to act as supported catalysts for the oxidation of n-pentane and n-hexane, with molecular oxygen under relatively mild reaction conditions, to the corresponding ketones (with good selectivities) and alcohols (in smaller amounts). cis- [VO(OCH3)(ma)2] 1 provides the best results in both cases and the effects of various factors (temperature, time, O2 pressure, catalyst amount) were also investigated towards the optimization of the reaction conditions. 2-pentanone (84% selectivity) and a small amount of 2-pentanol are formed from n-pentane at 150°C, p(O2) = 15 atm, while 2-hexanone (58% selectivity), 1-hexanol and acetic acid are obtained from n-hexane at 160°C, p(O2) = 10 atm. The involvement of a carbon- and oxygen-centred radical mechanism is suggested by experiments with free radical traps. Heteroaromatic acids were tested as possible co-catalysts and 2-pyrazinecarboxylic acid was the most effective one. Thermogravimetric analysis (TGA) indicates the catalyst is stable up to ca. 220°C and inductive couple plasma (ICP) shows a notable extensive vanadium loss from the supported catalyst after the reaction, allowing further use of the catalyst even without reactivation.
G.S. Mishra, A.J.L. Pombeiro, Applied Catalysis A: General 304 (2006) 185-194

A1048 – Study of nickel catalyst in oscillating regime of methane oxidation by means of gravimetry and mass-spectrometry

The application of the thermogravimetric analysis (TGA) combined with on-line mass-spectrometry analysis of the effluent gas mixture from the reactor and temperature programmed reduction (TPR) experiments allowed to obtain information about the content of oxygen and carbon in Ni catalysts during the oscillatory behaviour of methane oxidation. It was demonstrated that the significant variation of the oxygen content (several tens layers) in the Ni catalyst occurred during the oscillatory behaviour of methane oxidation. Together with the visual observation of the color changes due to the periodic variation of the Ni valence these data prove that the oxidation-reduction processes play the crucial role in the origin of the oscillatory behaviour during the methane oxidation over Ni catalysts. It was shown that during oscillatory behaviour of methane oxidation the catalyst contains the significant amount of deposited carbon, atleast, in two different forms. One of them is characterised by the higher reactivity and probably the higher state of the distribution on a metallic surface. The higher activity form of carbon prevails in the reduced state of the nickel catalyst. Another carbon form is characterised by the lower reactivity and, likely, does not noticeably effect the oscillations during methane oxidation.
V.Y. Bychkov, Y.P. Tyulenin, V.N. Korchak, E.L. Aptekar, Applied Catalysis A: General 304 (2006) 21-29

A1050 – Silicon based oxidation-resistant coatings on Ti6242 alloy by dynamic ion mixing

The influence of SixCy and SixNy amorphous coatings on the oxidation resistance of a Ti6242 (Ti-6Al-2Sn-4Zr-2Mo) alloy was investigated. They were produced at room temperature by the dynamic ion mixing technique combining physical vapour deposition with simultaneous bombardment with 120 keV Ar+ ions. Isothermal oxidation tests were carried out at 600°C in 1 atm flowing synthetic air (80% N2, 20% O2) demonstrating a considerable reduction ( ~ two orders of magnitude) of the oxidation rate for at least 100 h. The structural modifications after oxidation were investigated by XPS, XRD, SEM, SIMS. The formation of SiO2 is detected as the main oxidation product in the coating and the formation of Ti-Si compounds is also observed in the coating/substrate interface region. The crystallisation of SixNy is not detected and for SixCy only some traces of beta-SiC could exist. The improvement of oxidation resistance of Ti6242 is discussed in relation with the intrinsic properties of the coatings and with the interface mixing and ion beam densification.
J.P. Rivière, L. Pichon, M. Drouet, A. Galdikas, D. Poquillon, Surface & Coatings Technology 200 (2006) 5498 - 5504

A1052 – Ion flotation of germanium from fly ash aqueous leachates

The germanium - together with other metals and metalloids contained in the fly ash generated in the Integrated Gasification in Combined Cycle (IGCC) of Elcogas plant (Puertollano, Spain) - may be extracted by aqueous leaching. Here we report the study of the selective recovery of germanium from aqueous leachate by means of ion flotation, using a complexating agent and a surfactant as collector. The use of different ligands with dodecylamine as collector and the effect of the pH were evaluated. The optimal conditions found for germanium recovery are: catechol as complexating agent, triple stoichiometric ratio of the reagents and pH 4-7. In these conditions, germanium recovery was 100% and the extraction of impurities was reduced. The recovered froth was burned and characterized by thermogravimetric analysis (TGA), X-ray fluorescence (XRF) and X-ray diffraction (XRD). A high Ge product (53% GeO2) was obtained.
A. Hernandez-Exposito, J.M. Chimenos, A.I. Fernandez, O. Font, X. Querol, P. Coca, F. Garcia Pena, Chemical Engineering Journal 118 (2006) 69-75

A1051 – Properties and structure of cyanate ester/polysulfone/organoclay nanocomposites

In this paper, a cyanate ester (CE) matrix has been modified with polysulfone and an organic montmorillonite (Nanofil 919). The blend was thermally cured in presence of copper acetylcetonate and nonylphenol. The morphology of the cured materials was investigated by wide angle Xray, scanning and transmission electron microscopy techniques. An intercalate structure of silicate platelets in the cyanate matrix has been obtained. Furthermore, results of thermogravimetric analysis (TGA) suggest that CE/PSF/Nanofil 919 nanocomposites have higher thermal stability than the neat resin, increasing the onset decomposition temperature. Flexural strength distributions of modified and neat cyanate matrices were obtained by testing the materials in three-point bending. The results were analyzed within the framework of Weibull statistics. The flexural behavior of the resins demonstrated to be sensitive to the intrinsic flaw distribution. The modified system displayed higher fracture toughness and impact strength compared to pure CE. Dynamic mechanical analysis (DMA) studies confirmed that the PSF modified matrix developed a twophase morphology consisting of spherical PSF dispersed in a thermoset matrix.
I. Mondragon, L. Solar, A. Nohales, C.I. Vallo, C.M. Gomez, Polymer 47 (2006) 3401-3409

A1054 – Hybrid organic-inorganic materials: Layered hydroxy double salts intercalated with substituted thiophene monomers

The present paper describes the synthesis and characterization of Layered Hydroxy Double Salts (HDSs) containing substituted thiophene anions (2-thiophenecarboxylate, 3-thiophenecarboxylate, and 3-thiopheneacetate). The HDSs host was synthesized via hydrothermal method and the organic anions were incorporated between the sheets by anion-exchange reaction. The materials were characterized by powder X-ray diffraction (PXRD), thermal gravimetric (TG) analysis and electron spin resonance (ESR) spectroscopy. For the 2D-hybrid materials, the basal spacing is found to be consistent with the formation of bilayers of the intercalated organic monomers. For the hybrid material formed after intercalation of 3-thiopheneacetate anion, the ESR signals suggest that the monomers connect each other directly forming small oligomers, whereas this process is not occurring for the two other monomers presenting short alkyl chain. The TG analyses show different stages of thermal decomposition between HDSs host and 2D-hybrid materials, underlining the enhanced thermal stability of the hybrid assembly.
J. Tronto, F. Leroux, M. Dubois, C. Taviot-Gueho, J. Barros Valim, Journal of Physics and Chemistry of Solids 67 (2006) 978-982

A1053 – Recycling of chemicals from alkaline waste generated during preparation of UO3 microspheres by sol-gel process

Internal gelation process, one of the sol-gel processes for nuclear fuel fabrication, offers many advantages over conventional powder pellet route. However, one of the limitation of the process is generation of large volume of alkaline liquid waste containing hexamethylenetetramine, urea, ammonium nitrate, ammonium hydroxide etc. Presence of ammonium nitrate with hexamethylenetetramine and urea presents a fire hazard which prevents direct disposal of the waste as well as its recycle by evaporation. The paper describes the studies carried out to suitably process the waste. Nitrate was removed from the waste by passing through Dowex 1 x 4 anion exchange resin in OH- form. 1.0 M NaOH was used to regenerate the resin. The nitrate-free waste was further treated to recover and recycle hexamethylenetetramine, urea and ammonium hydroxide for preparation of UO3 microspheres. The quality of the microspheres obtained was satisfactory. An optimized flow sheet for processing of the waste solution has been suggested.
A. Kumar, T.V. Vittal Rao, S.K. Mukerjee, V.N. Vaidya, Journal of Nuclear Materials 350 (2006) 254-263

A1056 – Hydrocalumite-type materials: 1. Interest in hazardous waste immobilization

This study investigated the incorporation of Cr, V and Si oxoanions into hydrocalumite. Hydrocalumite together with ettringite form during the hydration of Portland cement and the use of these materials in hazardous waste immobilization is of current concern. The anion uptake was examined in terms of the structural characteristics by means of thermogravimetric analysis, infrared spectroscopy, X-ray diffraction (XRD) and in situ high temperature X-ray diffraction (HTXRD). The syntheses were carried out by coprecipitation or exchange reaction. The short interlamellar distances observed for Ca2Al-V2O7 and Ca2Al-SiO4 phases, 7.90 and 10.93 Å , respectively, are explained by a grafting process onto the hydroxide layers. The good crystallinity of Ca2Al-CrO4 allowed the refinement of the cell parameters in the P-3 space group with a=5.7507(3) Å and c=20.164(2). A structural model is proposed with CrO4 species close to the seventh coordination position of Ca atoms. In situ HTXRD measurements in the temperature range 25-350°C reveal different thermal behaviors depending on the oxoanion. At low temperature, a dehydration-hydration process partly reversible was observed for Ca2Al-V2O7 and Ca2Al-CrO4 phases, between 100-200 and 50-120°C, respectively. At higher temperature, strong interlayer contractions were observed due to a pillaring process: ?d/d= -13% for Ca2Al-V2O7 at 200°C, ?d/d= -32% for Ca2Al-CrO4 at 250°C and ?d/d= -35% for Ca2Al-SiO4 at 135°C.
R. Segni, L. Vieille, F. Leroux, C. Taviot-Guého, Journal of Physics and Chemistry of Solids 67 (2006) 1037-1042

A1055 – Preparation of montmorillonite clays containing DTMPPA for Zinc extraction

Di(2,4,4-trimethylpentyl)phosphinic acid, 'DTMPPA' (Cyanex 272), was introduced into homoionic clays containing sodium by using two methods: a dry impregnation method (process 1) and an intercalation method (process 2). The total amount of loaded extractant was determined by NaOH titration of washings and/or mother-solutions in both cases. The solids obtained were characterized by infrared spectroscopy (IR), X-Ray diffraction and TGA-DTA analysis. The montmorillonite clays containing DTMPPA were used to successfully remove zinc from sulphuric dilute acidic solutions (pH 2-5), at constant ionic strength, I=1. The metal extraction depends on pH. The clay containing DTMPPA loaded by process 1, that contains more DTMPPA than the clay loaded by process 2, shows a better performance in the extraction of zinc.
D. Bouazza, H. Miloudi, M. Sassi, A. Boos, G. Goetz, A. Tayeb, A. Bengueddach, Journal of Physics and Chemistry of Solids 67 (2006) 1032-1036

A1057 – Chemistry and electrochemistry of nanostructured iron oxyhydroxides as lithium intercalation compounds for energy storage

The structural characterization and electrochemical performance of three nanosized iron oxyhydroxides (beta-FeOOH, gamma-FeOOH and delta-FeOOH) are reported in this work. The interest of having small particle sizes is to be able to circumvent the low intrinsic ionic conductivity of these materials through the increase of the active volume proportion of the operating grain, during the insertion process. Low temperature synthesis routes, in aqueous media, were thus used to obtain such crystallites with nanometer dimensions. The theoretical specific capacity of these materials is as high as 300 mA h g-1 which is actually very interesting for lithium batteries applications. However, the electrochemical behaviour greatly depends on the structure of the compounds. A phase transformation was, for example, evidenced in the case of gamma-FeOOH first lithiation whereas the best performance were obtained with beta-FeOOH, which develops a stable capacity of 180 mA h g-1, after 10 cycles, at C/10.
C. Benoit, C. Bourbon, P. Berthet, S. Franger, Journal of Physics and Chemistry of Solids 67 (2006) 1265-1269

A1060 – Synthetic hydromagnesite as flame retardant. Evaluation of the flame behaviour in a polyethylene matrix

Synthetic hydromagnesite obtained from an industrial by-product was evaluated as a non-halogenated flame retardant. It was used in combination with aluminium hydroxide (ATH) and compared with commercial flame retardants like magnesium hydroxide (MH) and natural hydromagnesite-huntite (U) in a polyolefin system of low-density polyethylene/poly(ethylene-co-vinyl acetate) (LDPE/EVA). The thermal stability and flame behaviour of the halogen free flame retarded composites were studied by thermogravimetric and differential thermal analysis (TG-DTA), limiting oxygen index (LOI), epiradiateur and cone calorimeter. It has been shown that synthetic hydromagnesite could be an alternative solution to the use of MH in non-halogenated flame retardant systems in EVA.
L. Haurie, A.I. Fernandez, J.I. Velasco, J.M. Chimenos, J-M. Lopez Cuesta, F. Espiell, Polymer Degradation and Stability 91 (2006) 989-994

A1059 – Template synthesis and characterization of PbTiO3 nanowire arrays from aqueous solution

Highly ordered PbTiO3 nanowire arrays were first reported by fabricating within the pores of anodic aluminum oxide (AAO) template in the aqueous solution by liquid-phase deposition method. The structure and morphology of PbTiO3 nanowire arrays were characterized by SEM and TEM, respectively. The XRD result shows that desired stoichiometric composition could be easily obtained preparing the treatment solution during post-annealing in order to crystallize the nanowires. TEM analyses confirmed that the obtained nanowires composed of large crystals than others made by sol-gel methods. Finally, a possible growth mechanism of the PbTiO3 nanowires is discussed.
M.C. Hsu, I.C. Leu, Y.M. Sun, M.H. Hon, Journal of Solid State Chemistry 179 (2006) 1421-1425

A1058 – Preparation of nanowires of M substituted manganese dioxides (M=Al, Co, Ni) by the electrochemical-hydrothermal method

A variety of gamma-MnO2 compounds containing a metal M (with M=Al, Co or Ni) has been synthesized using the electrochemical-hydrothermal method. Depending on the selected synthesis parameters (temperature, pH, current density, presence of M) various structures and morphologies were obtained for the deposits. The experimental conditions allowing us to prepare M-containing gamma-MnO2 nanowires, and the structural and physico-chemical characteristics of the obtained samples are presented. The electrochemical Li insertion behavior of these M-containing gamma-MnO2 nanowires is briefly described.
E. Machefaux, A. Verbaere, D. Guyomard, Journal of Physics and Chemistry of Solids 67 (2006) 1315-1319

A1062 – Oxygen nonstoichiometry and mixed conductivity of SrFe(1-x)MxO(3-d) (M = Al, Ga): Effects of B-site doping

The oxygen nonstoichiometry, electrical conductivity and Seebeck coefficient of perovskite-related SrFe(1-x)GaxO(3-d) (x = 0 - 0.2) and SrFe(1-x)AlxO(3-d) (x = 0.1-0.3) were studied in the temperature range 923-1223 K at oxygen partial pressures varying from 10^(-20) to 0.3 atm. The substitution of iron with gallium was found to promote long-range ordering of oxygen vacancies, resulting in the perovskite => brownmillerite transition at moderate oxygen pressures, and to decrease the mobility of the p-type electronic charge carriers. Opposite tendencies are observed for aluminum doping, which causes a higher oxygen nonstoichiometry in oxidizing atmospheres. As suggested by atomistic simulations of highly oxygen-deficient ferrite lattices, this behavior is associated with oxygen-vacancy trapping near Al3+ having energetically favorable tetrahedral coordination, whereas Ga3+ cations with preferential octahedral coordination in the perovskite lattice tend to repulse vacancies towards oxygen sites surrounded by iron and thus destabilize the structure. The relatively low hole mobility, with activation energies of 0.18-0.33 eV, indicates a small-polaron conduction mechanism. Under reducing conditions the oxygen content and ionic transport in brownmillerite-type polymorphs of SrFe(1-x)GaxO(3-d), exhibiting a relatively wide range of oxygen stoichiometry variation, are both lower compared to the Al-containing materials characterized by the co-existence of perovskite- and brownmillerite-like domains.
M.V. Patrakeev, V.V. Kharton, Y.A. Bakhteeva, A.L. Shaula, I.A. Leonidov, V.L. Kozhevnikov, E.N. Naumovich, A.A. Yaremchenko, F.M.B. Marques, Solid State Sciences 8 (2006) 476-487

A1061 – A comparative study of the Ruddlesden-Popper series, La(n+1)Ni(n)O(3n+1) (n=1, 2 and 3), for solid-oxide fuel-cell cathode applications

A comparative investigation of the much-studied La2NiO(4+d) (n=1) phase and the higher-order Ruddlesden-Popper phases, La(n+1)Ni(n)O(3n+1) (n=2 and 3), has been undertaken to determine their suitability as cathodes for intermediate-temperature solid-oxide fuel cells. As n is increased, a structural phase transition is observed from tetragonal I4/mmm in the hyperstoichiometric La2NiO4.15 (n=1) to orthorhombic Fmmm in the oxygen-deficient phases, La3Ni2O6.95 (n=2) and La4Ni3O9.78 (n=3). High temperature d.c. electrical conductivity measurements reveal a dramatic increase in overall values from n=1, 2 to 3 with metallic behavior observed for La4Ni3O9.78. Impedance spectroscopy measurements on symmetrical cells with La0.9Sr0.10Ga0.80Mg0.20O3-d (LSGM-9182) as the electrolyte show a systematic improvement in the electrode performance from La2NiO4.15 to La4Ni3O9.78 with ~ 1 ? cm2 observed at 1073 K for the latter. Long-term thermal stability tests show no impurity formation when La3Ni2O6.95 and La4Ni3O9.78 are heated at 1123 K for 2 weeks in air, in contrast to previously reported data for La2NiO4.15. The relative thermal expansion coefficients of La3Ni2O6.95 and La4Ni3O9.78 were found to be similar at ~ 13.2 x 10^(-6) K-1 from 348 K to 1173 K in air compared to 13.8 x 10^(-6) K-1 for La2NiO4.15. Taken together, these observations suggest favourable use for the n=2 and 3 phases as cathodes in intermediate-temperature solid-oxide fuel cells when compared to the much-studied La2NiO4+d (n=1) phase.
G. Amow, I.J. Davidson, S.J. Skinner, Solid State Ionics 177 (2006) 1205-1210

A1064 – Synthesis and evaluation of the mucoadhesivity of a CD-chitosan derivative

Combining mucoadhesive characteristics of a biodegradable polymer such as chitosan with the potential to enhance drug release by increasing the solubility of poorly water-soluble drugs has great potential for pharmaceutical technology and drug delivery design. Polymeric delivery systems have been extensively researched in an attempt to achieve modified drug release. Cyclodextrins (CD) offer an alternative approach. These cyclic oligosaccharides have the ability to form non-covalent complexes with a number of drugs altering their physicochemical properties. In the continuing challenge to improve the properties of delivery systems, this paper focuses on the modification of chitosan by introducing beta-cyclodextrin and to test the mucoadhesive strength and inclusion properties of this synthesised cyclodextrin-polymer. beta-Cyclodextrin was successfully grafted onto a chitosan chain polymer with a cyclodextrin grafting yield of 7% and a CD-chitosan yield of 85%. Although the complexation of (+)-catechin by the grafted beta-CD was found to be about five times weaker than that by the beta-CD monoaldehyde and natural beta-CD, the inclusion properties of the chitosan-CD remain promising. The mucoadhesive properties of chitosan-CD were compared to that of pectin (reference) and the parent chitosan with the use of a tensile separation test. The chitosan-CD showed mucoadhesive strengths of 12% stronger than pectin, but 13.5% weaker than the parent chitosan. The synthesised chitosan-CD-polymer exhibits characteristics of a possible mucoadhesive drug delivery system with some inclusion properties from beta-cyclodextrin.
J.P. Venter, A.F. Kotzé, R. Auzély-Velty, M. Rinaudo, International Journal of Pharmaceutics 313 (2006) 36-42

A1067 – From V2O5 foam to VO2(B) nanoneedles

Nanoneedles B phase VO2 with high crystallinity was hydrothermally synthesized from the foam prepared by mixing V2O5, aniline and H2O in the mol ratio 1:1:258. The samples have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction and thermal analysis. Regularly sized VO2(B) nanoneedles have the following dimensions: 0.5-5 µm in length and about 50 nm in average diameter. According to transmission electron microscopy investigations, the V2O5 crystals resulting from the foam exhibit nanoparticles sizes between 50 and 100 nm. Thisway of synthesis provides a newsimple and elegant route to elaborate the vanadium dioxide VO2(B) nanoneedles and V2O5 nanoparticles under soft conditions.
F. Sediri, F. Touati, N. Gharbi, Materials Science and Engineering B 129 (2006) 251-255

A1066 – Phase equilibria and solidification of Mg-rich Mg-Al-Zn alloys

Phase equilibria in Mg-rich corner of Mg-Al-Zn system are analyzed in detail. Thermodynamic calculations are compared with literature data and own key experimental results by means of DSC and DTA measurements. The detailed comparison strongly supports the reliability of the selected thermodynamic description. Furthermore, our focus is placed on proper interpretation of experimental results obtained by thermal analysis. Based on thermodynamic calculation, it is clarified that a signal observed in thermal analysis, which was interpreted as end of solidification in the literature, is related to the start of the monovariant eutectic reaction L + (Mg) + gamma-Mg17Al12 under non-equilibrium condition and the solidification process ends at lower temperature. This fact is supported by our microstructural observation.
M. Ohno, D. Mirkovic, R. Schmid-Fetzer, Materials Science and Engineering A 421 (2006) 328-337

A1065 – The influence of water on the intercalation of epoxy monomers in Na-montmorillonite

The intercalation of a typical UV-curable epoxy monomer (CE) in unmodified montmorillonite and the effect of hydration on the intercalation reaction are studied. Montmorillonite in the sodium form was submitted to a controlled hydration/dehydration cycle and the water content was checked by TGA/XRD analyses. The structure of the hydrated Na+-montmorillonite was determined from the values of the basal spacings and from the water content of the hydrated form: a coordination of four water molecules per Na ion was found, corresponding to a minimum of energy calculated by molecular dynamics simulation. When dispersing the clay in the CE monomer, the anhydrous Na+-montmorillonite did not show any intercalation; on the contrary the hydrated form showed an increase of the basal spacing. A possible mechanism to explain the intercalation of the CE monomers is proposed.
R. Bongiovanni, D. Mazza, S. Ronchetti, E.A. Turcato, Journal of Colloid and Interface Science 296 (2006) 515-519

A1068 – Bi-phase MOR/MFI-type zeolite core-shell composite

Core-shell zeolite composites possessing a mordenite core and a shell of intergrown silicalite-1 crystals were synthesized. A classical hydrothermal treatment of mordenite crystals with a silicalite-1 precursor mixture did not result in the formation of an extended silicalite- 1 layer on the mordenite surface. The incompatibility between the core crystals and the shell precursor was circumvented by adsorption of nanoseeds on the core surface, which upon a subsequent hydrothermal treatment induced the formation of a well intergrown shell. The kinetics of shell growth was studied at 150 and 200°C and the optimum conditions further used for the preparation of composites subjected to XRD, SEM, TG/DTA, EDS and X-ray fluorescence analyses. The integrity of the shell layer was tested by N2 adsorption measurements on materials comprising Na- and Na,H-mordenite and a non-calcined tetrapropylammonium (TPA)-containing shell, the latter being non-permeable for the N2 molecules. These measurements showed that 96-98% of the mordenite crystals were covered with a defect-free TPA-silicalite-1 shell after a single hydrothermal treatment. A characteristic feature of the obtained composites is the relatively large single crystal core and the very thin polycrystalline shell. Thus, the relatively large active part of the composite is covered by a tiny shell that ensures fast kinetics.
Y. Bouizi, L. Rouleau, V.P. Valtchev, Microporous and Mesoporous Materials 91 (2006) 70-77

A1070 – Effect of drying temperature on structure, phase transformation of sol-gel-derived lead zirconate titanate powders

Lead zirconate titanate (PZT) (53/47) powders were prepared by a cheating acetate sol-gel process. The drying temperature effect on crystallization behavior was conducted to determine the best conditions for preparing high content of perovskite PZT powders in the morphotropic region. DSC/TG analysis, FT-IR spectrum and X-ray diffraction were carried out to identify the reaction sequences and calculated the activation energy of every transition temperature during the drying procedures. In the present work, well-crystallized, single-phase perovskite PZT powders were obtained after drying PZT stock solution at 300°C for 1 h, then heat treatment at 600°C for 30 min. The dependence of this crystallization temperature on the drying conditions was discussed.
T-.I Chang, J-L. Huang, H-P. Lin, S-C. Wang, H-H. Lu, L. Wu, J-F. Lin, Journal of Alloys and Compounds 414 (2006) 224-229

A1069 – Adsorption of copper(II), nickel(II) and cobalt(II) ions from aqueous solution by methacrylic acid/acrylamide monomer mixture grafted poly(ethylene terephthalate) fiber

A reactively fibrous adsorbent was prepared by graft copolymerization of methacrylic acid (MAA)/acrylamide (AAm) monomer mixture onto poly(ethylene terephthalate) (PET) fiber and characterized by Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The adsorption of Cu(II), Ni(II) and Co(II) ions from aqueous solution by the reactive fiber was examined by batch equilibration technique. The effects of graft yield, pH, adsorption time, initial ion concentrations and adsorption temperature on the adsorption amount of ions were investigated. The reusability and selectivity of the reactive fiber were also investigated. The results showed that the adsorption of the metal ions followed the following order Cu(II) > Ni(II) > Co(II). The adsorption amounts of ions increased with the increase of grafting yield, shaking time, and pH of the medium. The adsorption amounts of Ni(II) and Co(II) ions increased but Cu(II) ions were not affected with increasing adsorption temperature. It was found that the adsorption isotherm of the ions fitted Langmuir-type isotherms. From the Langmuir equation the adsorption capacity was found as 31.25 mg/g fiber for Cu(II), 43.48 mg/g fiber for Ni(II), and 27.17 mg/g fiber for Co(II), respectively. The competitive adsorption tests verified that this reactive fiber possessed good adsorption selectivity for Cu(II) with the coexistence of Co(II) and Ni(II). It can be regenerated by 1M HNO3 without losing their activity.
R. Coskun, C. Soykan, M. Saçak, Separation and Purification Technology 49 (2006) 107-114

A1072 – Hydroxylation of benzene and phenol in presence of vanadium grafted Beta and ZSM-5 zeolites

Vanadium grafted zeolites type Beta and ZSM-5 were investigated for direct oxidation of benzene to phenol and hydroxylation of phenol with hydrogen peroxide in acetonitrile media at 353 K. The introduction of vanadium was done by reductive solid state ion exchange. The morphological characterisation of samples and the stability of the vanadium sites were examined before and after the reaction by applying FTIR, UV-Vis techniques and reduction/oxidation cycles (TPR/TPO). The results proved that the vanadium sites had retained their multiple oxidation state when used in liquid phase oxidation at high vanadium atom efficiency for the reaction product.
R. Dimitrova, M. Spassova, Catalysis Communications 8 (2007) 693-696

A1071 – Structure and properties of the alumina-supported vanadia catalysts for ethylbenzene dehydrogenation in the presence of carbon dioxide

Dehydrogenation of ethylbenzene (EB) to styrene (ST) in the presence of carbon dioxide was investigated over a series of alumina-supported vanadia catalysts (VOx/Al2O3) with the vanadium loading of 0.40-3.00 mmol/g Al2O3. The catalysts were characterized by XRD, H2-TPR, TGA, UV-Raman and UV-vis spectroscopy. The catalytic behaviour as well as the structure of VOx species on alumina depends strongly on the vanadium loading. Catalytic activity increases firstly with increasing the vanadium loading and the STyield reaches a maximum value of 69.7% at a vanadium loading of 1.50 mmol/g Al2O3, and then the activity decreases with a further increase in the vanadium loading. This may be related to the fraction of VOx exposed on the domain surfaces and the reducibility of the surface VOx species. The catalysts with different vanadium loadings are also different in the deactivation mechanism. The deactivation of VOx/Al2O3 with vanadium loading below 1.50 mmol/g Al2O3 is mainly ascribed to coke deposition, while the deep reduction of V5+ species becomes an important factor in the deactivation of catalyst with higher vanadium loading. EB dehydrogenation over VOx/Al2O3 in the presence of carbon dioxide exhibits higher ST yield than that in the presence of an inert nitrogen atmosphere. Such a result can be attributed to the facts that carbon dioxide as a weak oxidant can eliminate hydrogen produced during EB dehydrogenation, regain the oxidation state (lattice oxygen) of reduced vanadium species and alleviate the catalyst deactivation.
S. Chen, Z. Qin, X. Xu, J. Wang, Applied Catalysis A: General 302 (2006) 185-192

A1075 – The role of nanostructure in nitrogen-containing carbon catalysts for the oxygen reduction reaction

Catalysts for the oxygen reduction reaction (ORR) were prepared by the high-temperature pyrolysis of acetonitrile over Vulcan carbon XC-72, and Vulcan carbon impregnated with 2 wt% Fe or 2 wt% Ni in the form of an acetate salt. The catalysts were characterized by BET surface area analysis, BJH pore size distribution, electrical conductivity testing, transmission electron microscopy (TEM), temperature-programmed oxidation, thermogravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and rotating disk electrode half-cell testing. The most active catalysts were formed when Fe was added to the support before the pyrolysis; however, samples in which Ni or no metal was added still showed increased activity for oxygen reduction compared with untreated carbon. The most active catalyst had a significantly higher amount of pyridinic nitrogen, as determined from XPS. A hypothesis has been proposed to explain this trend based on the formation of different nanostructures depending on which support material is used for the acetonitrile decomposition. According to this proposed explanation, nitrogen-containing carbon samples with nanostructures resulting in exposure of more edge planes (the plane in which pyridinic nitrogen is found) will be more active for the ORR. TEM images of the samples strongly support this hypothesis. Further research is needed to positively identify the active site for oxygen reduction; however, this site is likely located on carbon edge planes.
P.H. Matter, L. Zhang, U.S. Ozkan, Journal of Catalysis 239 (2006) 83-96

A1074 – Improvement of mechanical properties of poly(DL-lactide) films by blending of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(DL-lactide) (PDLLA) were blended at different ratios in an attempt to form a biomaterial with suitable properties for nerve regeneration. FT-IR and X-ray analysis showed that the blending of the PDLLA component did not alter the helical structure of PHBHHx, but did lead to a reduction of crystallinity. Differential scanning calorimetry (DSC) analysis indicated that the two polymers were immiscible in the melted state. The mechanical properties of certain composite films were more desirable than those of unblended PDLLA films. Blends consisting of PDLLA and PHBHHx at ratios of 2:1 and 1:2 exhibited a lower elastic modulus and a higher elongation at break compared to unblended PDLLA. ELISA results indicated that the amount of fibronectin adsorbed on composite films was much higher than the amount adsorbed on PDLLA film. The results of this study demonstrate the feasibility of using PDLLA/PHBHHx blended materials for biomedical applications.
Y. Gao, L. Kong, L. Zhang, Y. Gong, G. Chen, N. Zhao, X. Zhang, European Polymer Journal 42 (2006) 764-775

A1073 – Para-selectivity of modified HZSM-5 zeolites by nitridation for ethylation of ethylbenzene with ethanol

The modification of HZSM-5 zeolite was carried out by nitridation of commercial HZSM-5 zeolites with flowing pure ammonia at high temperature. The modified HZSM-5 zeolites maintained high crystallinity and high specific surface areas of precursors testified by XRD, BET and SEM analysis. Compared with parent HZSM-5, the surface strong acid sites of modified HZSM-5 zeolites decreased severely as characterized by means of NH3-TPD analysis and pyridine-IR spectroscopy shows that nitridation mainly occurred in Bronsted acid sites. The modified HZSM-5 zeolites exhibited much higher selectivity to para-diethylbenzene (DEB) and significantly enhanced stability than parent HZSM-5 when applied in the reaction of ethylbenzene ethylation with ethanol. The reduction of strong acid sites can suppress the isomerization of para-diethylbenzene and improve the para-selectivity. The effects of nitrogen contents in modified zeolites on the conversion and selectivity to p-DEB were also studied.
X. Guan, N. Li, G. Wu, J. Chen, F. Zhang, N. Guan, Journal of Molecular Catalysis A: Chemical 248 (2006) 220-225

A1076 – Cathodic electropolymerization on the surface of carbon nanotubes

This paper reports functionalization of carbon nanotubes (CNTs) via cathodic electropolymerization. Indeed, this technique ensures good control of the grafted polymer (PMAN in our study) on the surface of the substrates (CNTs). The study was done both on singlewall nanotubes (SWNTs) and multi-wall nanotubes (MWNTs) following two distinct approaches: on one hand, the CNTs were dispersed in an organic solution under stirring. This option aims at their functionalization by transient contact with a metallic cathode, but did not give promising results. On the other hand, the CNTs were synthesized (produced) on the surface of an electrode that will be used as cathode in the grafting process. The surface modifications were followed by SEM, XPS, TGA (Thermo Gravimetry Analysis).
T. Defever, G. Deniau, S. Palacin, L. Goux-capes, S. Barrau, M. Mayne-l'hermite, J-P. Bourgoin, Journal of Electroanalytical Chemistry 589 (2006) 46-51

A1078 – Mixed conductivity and Mössbauer spectra of (La0.5Sr0.5)(1-x)Fe(1-y)AlyO(3-d) (x = 0-0.05, y = 0-0.30)

Aluminum incorporation in the rhombohedrally distorted perovskite lattice of (La0.5Sr0.5)(1-x)Fe(1-y)AlyO(3-d) (x = 020:05, y = 020:30) decreases the unit cell volume and partial ionic and p-type electronic conductivities, while the oxygen nonstoichiometry and thermal expansion at 900-1200K increase on doping. The creation of A-site cation vacancies has an opposite effect on the transport properties of Al-substituted ceramics. The maximum A-site deficiency tolerated by the (La,Sr)(Fe,Al)O(3-d) structure is however limited, close to 3-4%. The Mössbauer spectroscopy revealed progressive localization of electron holes and a mixed charge-compensation mechanism, which results in higher average oxidation state of iron when Al3+ concentration increases. The average thermal expansion coefficients of (La0.5Sr0.5)(1-x)Fe(1-y)AlyO(3-d) are (12.2-13.0) x 10^(-6) K-1 at 300-900K and (20.1-30.0) x 10^(-6) K-1 at 900-1200K in air. The steady-state oxygen permeability (OP) of dense Al-containing membranes is determined mainly by the bulk ionic conductivity. The ion transference numbers at 973-1223K in air, calculated from the oxygen permeation and faradaic efficiency (FE) data, vary in the range 1 x 10^(-4) - 3 x 10^(-3), increasing with temperature.
V.V. Kharton, J.C. Waerenborgh, A.P. Viskup, S.O. Yakovlev, M.V. Patrakeev, P. Gaczynski, I.P. Marozau, A.A. Yaremchenko, A.L. Shaula, V.V. Samakhval, Journal of Solid State Chemistry 179 (2006) 1273-1284

A1077 – High-temperature phase equilibria in the oxide systems SrFe(1-x)GaxO2.5-SrFe(1-x)GaxO3 (x = 0, 0.1, 0.2)

X-ray powder diffraction, Raman scattering, equilibrium oxygen content and conductivity data are combined to construct hightemperature phase diagrams (T vs. delta) for the oxide systems SrFe(1-x)GaxO2.5-SrFe(1-x)GaxO3, where x = 0, 0.1, and 0.2. Depending on oxygen content and gallium doping, three different structural types are shown to exist at high temperatures including cubic perovskite-, cubic brownmillerite-, and orthorhombic brownmillerite-type structures. Substitution of gallium for iron is shown to extend the oxygen content and temperature limits where the cubic brownmillerite-type phase is stable.
I.A. Leonidov, M.V. Patrakeev, J.A. Bahteeva, E.B. Mitberg, V.L. Kozhevnikov, P. Colomban, K.R. Poeppelmeier, Journal of Solid State Chemistry 179 (2006) 1093-1099

A1081 – High-temperature oxidation resistance of Ta-Si-N films with a high Si content

The high-temperature oxidation resistance of ternary Ta-Si-N films with a high (>20 at.%) Si content deposited by reactive dc magnetron sputtering on silicon substrates was systematically investigated by means of a symmetrical high-resolution thermogravimetry in a flowing air up to an annealing temperature of 1300°C. Additional analyses including optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and the microhardness measurement were carried out as well. The obtained results showed an excellent high-temperature oxidation resistance Ta12Si26N62 films up to 1300°C. A slight oxidation starts just above 800°C and stops approximately at 1080°C due to the formation of a thin barrier oxide layer composed dominantly of orthorhombic Ta2O5 phase. The thickness of the oxide layer is almost constant with the annealing from 1080-1300°C (hoxide /hfilm~18%), however, the crystallinity is much improved. The microhardness decreases from 25 to 16 GPa with increasing annealing temperature due to the formation of the oxide layer of a lower microhardness. The microhardness and the oxide layer thickness almost do not change with increasing annealing time up to 1 h at a constant annealing temperature of 1300°C.
P. Zeman, J. Musil, R. Daniel, Surface & Coatings Technology 200 (2006) 4091-4096

A1080 – Dual layer silica coatings of SiC particle reinforcements in aluminium matrix composites

The development of double layer silica coating on SiC particles is demonstrated as a method to create an active barrier which improves wetting and reduces interfacial damage during the manufacturing by a liquid route of aluminium matrix composite reinforced with SiC particles. Coatings tested have a dual structure formed by an inner partially crystallized silica layer obtained by SiC particle oxidation, and an outer one produced by a sol-gel method which forms an amorphous silica layer. Studies of thermal gravimetry/differential thermal analysis (TG/DTA) have allowed the determination of the reactivity grade of different duplex coatings obtained by controlling the densification level of the outer layer, using different heat treatments for the coated particles. Similar studies on uncoated and single coated particles (only oxidised or sol-gel treated ones) were also carried out for comparative purposes. Microstructural studies were also applied to determine the influence of the coating treatments on the composite microstructure. The resulting coating increases the reactivity of the reinforcement in the first stages of the composite manufacture while it better protects the inner SiC from the molten aluminium etching.
J. Rams, A. Urena, M. Campo, Surface & Coatings Technology 200 (2006) 4017-4026

A1079 – Properties of reactively sputtered W-Si-N films

Recently, it has been found that ternary nitrides of the type Me-Si-N (Me=Ti, Zr, Ta, W, etc.) containing a low (<10 at.%) amount of Si can form nanocomposites with enhanced hardness. However, there is insufficient knowledge on properties of these nitride films with a high content of Si. This article reports on the d.c. reactive magnetron sputter deposition of W-Si-N films with a high (>20 at.%) content of Si and their physical and mechanical properties. Films were characterized by XRD, EDX, microhardness, elastic recovery, resistance to plastic deformation, macrostress ? and thermogravimetry. On the basis of a systematic investigation of the properties of reactively sputtered W-Si- N films it was found that (1) according to the elemental composition, which can be controlled by a variation of the partial pressure of nitrogen ( pN2), W-Si-N films are nanocomposites composed of a mixture of different phases, either WSi2+W+Si3N4 or Si3N4+WNx, when produced at low and high values of pN2, respectively; (2) the 4 to 5 Am thick W-Si-N films produced at high values of pN2 exhibit (i) an amorphous structure, (ii) the highest (~35 GPa) hardness and (iii) a relatively low (~1.6 GPa) compressive macrostress ?, (3) the maximum hardness Hmax does not depend on the energy density Ebi delivered to the growing film by bombarding ions but the value of Ebi must be higher than a minimum energy Ebimin~0.1 MJ/cm3, (4) H and ? of the hardest W-Si-N film do not depend on (i) the film thickness h up to 15 µm and (ii) the deposition temperature Ts up to 500°C and (5) the oxidation resistance is achieved up to approximately 800°C. Special attention is devoted to correlations between the film hardness and the content of Si3N4 in the film. The W-Si-N films with a higher content of Si and a higher N/Si ratio exhibit a higher H. Correlations between the hardness H, effective Young's modulus E*=E/(1-v2), elastic recovery We and the ratio H3/E*2 are also given (here v is the Poisson's ratio). The main conclusion resulting from this work is a finding that the high (>60 vol.%) content of Si3N4 in the W-Si-N film is not a sufficient condition to achieve the oxidation resistance exceeding 1000°C. The thermal stability of individual phases from which the Si based (Me-Si-N) nitride film is composed must be ensured too.
J. Musil, R. Daniel, J. Soldan, P. Zeman, Surface & Coatings Technology 200 (2006) 3886- 3895

A1083 – 3-Dimethylaminopropyl chalcogenolate complexes of palladium(II): Syntheses and characterization, including the crystal structures of [Pd(OAc)(ECH2CH2CH2NMe2)]2 . H2O (E = S, Se) and [PdCl(TeCH2CH2CH2NMe2)]2

The reactions of the sodium salts of 3-dimethylamino-1-propylchalcogenolates, prepared by sodium borohydride reduction of (Me2NCH2CH2CH2E)2 in methanol, with Na2PdCl4 yielded homoleptic [Pd(ECH2CH2CH2NMe2)2]6 (1) (E=S (1a); Se (1b); Te (1c)). When treated with [Pd(OAc)2]3 or Na2PdCl4, compounds 1 readily gave binuclear redistribution products [PdX(ECH2CH2CH2NMe2)]2 where X = OAc (2) (E=S (2a); Se (2b); or Cl (3)) (E = S (3a); Se (3b); Te (3c)), respectively. The terminal acetate/chloride ligands in 2b/3b can be substituted by other ionic ligands like PhSe . The complexes were characterized by elemental analysis, UV-Vis, IR and NMR spectroscopy. The structures of 2a, 2b and 3c were established by X-ray crystallography. Each molecule has a dimeric structure in which there are two chalcogenolate bridges from the chelating 3-dimethylamino-1-propylchalcogenolate ligands. On pyrolysis, compound 2b affords Pd17Se15.
S. Dey, V.K. Jain, B. Varghese, T. Schurr, M. Niemeyer, W. Kaim, R.J. Butcher, Inorganica Chimica Acta 359 (2006) 1449-1457

A1082 – Synthesis of nanocrystalline titania by hydrothermal method using cetyl pyridinium chloride as a template and its catalytic applications

Nano crystalline titanium dioxide predominantly in the anatase phase has been synthesized from titanium isopropoxide by dispersion technique using hydrothermal synthesis method in water-ethanol system. The material was characterized for its structural and textural properties using powder X-ray diffraction (XRD), TG-DTA, transmission electron microscopy (TEM) and by low temperature N2 adsorption at 77K. Both TEM and XRD data reveal a uniform and nanocrystalline TiO2 particles of 8 and 14 nm for the as synthesized and calcined samples respectively. The calcined sample showed photo catalytic activity in the decomposition of methylene blue in aqueous medium under both UV and visible light region. The results are compared with degussa P-25 TiO2 sample.
D. Bhange and V. Ramaswamy, Catalysis Communication xx (2007) xx-xx

A1084 – Synthesis and structure of Mu-33, a new layered aluminophosphate | ((CH3)3CNH3+)16(H2O)4 | [Al16P24O88(OH)8]

Mu-33, a new layered aluminophosphate with an Al/P ratio of 0.66, was obtained from a quasi non-aqueous synthesis in which tert-butylformamide (tBF) was the main solvent and only limited amounts of water were present. During the synthesis, tBF decomposed and the resulting protonated tert-butylamine is occluded in the as-synthesized material. The approximate structure was determined from data collected on a microcrystal (200 x 25 x 5 µm3) at the European Synchrotron Radiation Facility (ESRF) in Grenoble, but the quality of these data did not allow satisfactory refinement. Therefore the structure was refined using high-resolution powder diffraction data, also collected at the ESRF. The structure (P21/c, a = 9.8922(6) Å , b = 26.180(2) Å , c = 16.729(1) Å and beta = 90.4(1)° ) consists of anionic aluminophosphate layers that can be described as a sixring honeycomb of alternating corner-sharing AlO4 and PO4 tetrahedra with additional P-atoms above and below the honeycomb layer bridging between Al-atoms. The tert-butylammonium ions and water molecules located in the interlayer spacing interact via hydrogen-bonds with the terminal oxygens of the P-atoms. The characterization of this new aluminophosphate by 13C, 31P, 1H-31P heteronuclear correlation (HETCOR) and 27Al 3QMAS solid state NMR spectroscopy is also reported.
C. Marichal, J.M. Chézeau, M. Roux, J. Patarin, J.L. Jorda, L.B. McCusker, C. Baerlocher, P. Pattison, Microporous and Mesoporous Materials 90 (2006) 5-15

A1087 – Energetic and entropic contributions controlling the sorption of benzene in zeolites

The energetic and entropic contributions controlling the sorption of benzene on acidic (H/ZSM-5) and non-acidic (Silicalite-1) MFI type materials were studied using gravimetry, calorimetry and in situ IR spectroscopy to follow the qualitative and quantitative interactions of benzene with the pores and the functional SiOH and SiOHAl groups. The model derived to describe the sorption isotherms indicates the presence of sterically constrained sorption structures for benzene in MFI type materials. The interaction of benzene with the pore walls controls the sorption energetically, while the localized interaction with the bridging hydroxy groups contributes only to a minor degree. If benzene is located close to SiOHAl groups perturbed hydroxy groups are formed. Their wavenumber reflects the local sorption geometry of benzene as well as the acid strength of the hydroxy group and the base strength of benzene. Two perturbed hydroxy groups were observed for benzene adsorbed, which are assigned to two orientations of the molecules inside the pores, i.e., with the ring parallel to the pore wall and with the ring being oriented towards the bridging hydroxy groups. At higher coverage benzene adsorbs at SiOHAl groups additionally in an unconstrained environment, most probably at the pore openings.
A. Jentys, R.R. Mukti, H. Tanaka, J.A. Lercher, Microporous and Mesoporous Materials 90 (2006) 284-292

A1086 – Molecular dynamics of 4-n-octyl-4′-cyanobiphenyl in partially filled nanoporous SBA-type molecular sieves

The molecular dynamics of 4-n-octyl-4'-cyanobiphenyl (8CB) confined to the nanopores of new SBA-type molecular sieves was investigated in a wide temperature range using broadband dielectric spectroscopy (10^(-2)-10^9 Hz). One molecular sieve has a hexagonal structure of the pores while the other is a cellular nanoporous material. To explore the extent of surface interaction effects a high and a low filling degree were considered. For the molecular sieves with a high filling degree two relaxation regions were observed: a bulk-like relaxation process related to molecules, which behave as mesophase, located in the centre of the pores. The second relaxation process has a much lower relaxation rate than the former and is assigned to molecules located in a surface layer. The temperature dependence of its relaxation rates follows the Vogel-Fulcher-Tammann law, characteristic for glassy dynamics. For samples with a low filling degree only one relaxation process due to the surface layer was observed. Moreover, especially at the temperatures lower than the melting point of bulk 8CB, its relaxation rate is situated between the characteristic frequencies of the two relaxation processes observed for the pores with a high filling degree. This behaviour gives a measure of the extension of the influence of the wall on the neighbouring 8CB molecules. In addition, the differences revealed by the molecule dynamics inside the two types of nanoporous materials are related to both surface interactions and geometrical constraints.
L. Frunza, H. Kosslick, S. Frunza, A. Schönhals, Microporous and Mesoporous Materials 90 (2006) 259-270

A1085 – Two new aluminophosphates, IST-1 and IST-2: First examples of a dual templating role of water and methylamine in generating microporous structures

This study is aimed at exploring the ability of very small sized N-bearing molecules to generate and stabilize microporous aluminophosphates. Two new AlPO4-n materials, called IST-1 and IST-2, have been obtained in aqueous media using, as main template, methylamine (MA), directly added, or generated in situ from methylformamide (MF) degradation. While IST-1 topology proved to be novel, IST-2 appears structurally related to AlPO4-53(A). The obtained materials were characterized by powder XRD, TG/DSC, SEM and solid-state NMR. Tetraalkylammonium (TEA) cations were used as potential co-templates but only MA and water were found incorporated in the pore volumes of both structures, which argues for their true templating role. In IST-1, 13C solid-state NMR studies showed that half of MA species, presumably protonated, is H-bonded to framework oxygens while the other half surprisingly bonds directly to framework Al atoms. 13C NMR showed that only protonated MA occurs in IST-2 channels. TEA+ cations definitely do not play any specific template role. They indirectly favor the crystallization of IST-1 or IST-2 devoid from other crystalline or amorphous side phases, by interacting with part of the Al and P in solution and forming soluble [AlPO4(OH)]-[TEA,HMA] complexes, substantially modifying the compositions of gels precursors to each phase during nucleation and/or growth steps. While both IST-1 and IST-2 crystallize from gels of similar initial compositions, it was demonstrated that the new MA/T ratio (T = Al or P) obtained after in situ complexation was the key parameter that specifically governs the crystallization of each phase.
A. Fernandes, M.F. Ribeiro, C. Borges, J.P. Lourenço, J. Rocha, Z. Gabelica, Microporous and Mesoporous Materials 90 (2006) 112-128

A1089 – Description of organic compound vapor-phase sorption by geosorbents: Adequacy of the isotherm approximation

The approximation of isotherms of vapor-phase sorption of organic compounds (OC) is a long-standing problem. It is especially difficult to solve in case of natural heterogeneous sorbents (soils, sediments, aquifers, etc.) since these sorbents contain sites with different sorption activity. The aim of this work was the statistical evaluation of the adequacy of the approximation of isotherms of vapor-phase sorption of OC by geosorbents in water-unsaturated conditions by employing various fitting equations. Vapor sorption isotherms were measured by the static headspace gas-chromatographic analysis method for 27 various organic sorbates (13 hydrocarbons and 5 chlorinated hydrocarbons, 7 oxygenated and 2 nitrogenated OC) on geosorbents (6 soils typical for Middle Russia regions, separate soil layers of 2 dark-gray forest soils, natural zeolitecontaining material and bentonite clay, and two clay-humic complexes). The computer-assisted special sorption database with the corresponding software was created, and on the whole, 103 experimental sorption isotherms (86 isotherms measured and 17 taken from the literature) were used for the approximation. The adequacy of isotherm approximation by different sorption models was compared: Brunauer-Emmett-Teller (BET), modified BET (MBET), Pickett-Dellyes (PD), Guggenheim-Anderson-De Boer (GAB), Aranovich-Donohue (AD), Hinz (HZ) and polynomial (PN) equation. For the comparison of the adequacy of isotherm approximation by different equations, the following three criteria were used: (a) s5% - the average probability of the location of experimental sorption values within the range of 5% of the theoretical curve; (b) two interconnected parameters: R2 - the square of correlation coefficient and k - the slope tangent for the linear regression (VE; VT) at various sorbate activities; (c) D - relative sample variance as a characteristics of the optimal ratio between numbers of parameters of the fitting equation and its approximation quality. For the description of the vapor sorption of OC by geosorbents, the new MGAB equation (the modified GAB equation) was suggested. It is characterized by the optimal ratio between the 'complexity' of an equation (MGAB is a four-parametrical equation) and its approximation quality (MGAB shows one of the best isotherm approximations). The following rank of the decrease of the adequacy (upon D criterion) of examined fitting equations in relation to the OC sorption isotherm approximation in the whole isotherm range was formed: MGAB>HZ > PD>GAB>AD> PN.
I.P. Breus, A.A. Mishchenko, K.A. Potashev, V.A. Breus, Colloids and Surfaces A: Physicochem. Eng. Aspects 276 (2006) 122-133

A1088 – The influence of implanted yttrium on the cyclic oxidation behaviour of 304 stainless steel

High-temperature alloys are frequently used in power plants, gasification systems, petrochemical industry, combustion processes and in aerospace applications. Depending on the application, materials are subjected to corrosive atmospheres and thermal cycling. In the present work, thermal cycling was carried out in order to study the influence of implanted yttrium on the oxide scale adherence on 304 steel specimens oxidised in air at 1273 K. In situ X-ray diffraction indicates that the oxides formed at 1273 K are different on blank specimens compared to implanted specimens. Glancing angle XRD allows to analyse the oxide scale composition after cooling to room temperature. Experimental results show that yttrium implantation at a nominal dose of 10^17 ions cm-2 does not improve significantly the cyclic oxidation behaviour of the austenitic AISI 304 steel. However, it appears that yttrium implantation remarkably enhance the oxidation resistance during isothermal oxidation. It reduces the transient oxidation stage and the parabolic oxidation rate constant by one order of magnitude.
F. Riffard, H. Buscail, E. Caudron, R. Cueff, C. Issartel, S. Perrier, Applied Surface Science 252 (2006) 3697-3706

A1090 – Dimeric allylpalladium(II) complexes with pyrazolate bridges: Synthesis, characterization, structure and thermal behaviour

The synthesis, characterization and thermal behaviour of some new dimeric allylpalladium (II) complexes bridged by pyrazolate ligands are reported. The complexes [Pd(µ-3; 5-R2'pz)(?3-CH2C(R)CH2)]2 [R = H, R' = CH(CH3)2 (1a); R=H, R' = C(CH3)3 (1b), R = H, R' = CF3 (1c); R = CH3, R' = CH(CH3)2 (2a); R = CH3, R' = C(CH3)3 (2b); and R = CH3, R' = CF3 (2c)] have been prepared by the room temperature reaction of [Pd(?3-CH2C(R)CH2)(acac)](acac = acetylacetonate) with 3,5-disubstituted pyrazoles in acetonitrile solution. The complexes have been characterized by NMR (1H, 13C{1H}), FT-IR, and elemental analyses. The structure of a representative complex, viz. 2c, has been established by single-crystal X-ray diffraction. The dinuclear molecule features two formally square planar palladium centres which are bridged by two pyrazole ligands and the coordination of each metal centre is completed by allyl substituents. The molecule has non-crystallographic mirror symmetry. Thermogravimetric studies have been carried out to evaluate the thermal stability of these complexes. Most of the complexes thermally decompose in argon atmosphere to give nanocrystals of palladium, which have been characterized by XRD, SEM and TEM. However, complex 2c can be sublimed in vacuo at 2 mbar without decomposition. The equilibrium vapour pressure of 2c has been measured by the Knudsen effusion technique. The vapour pressure of the complex 2c could be expressed by the relation: ln (p/Pa)(±0.06) = 18047.3/T + 46.85. The enthalpy and entropy of vapourization are found to be 150.0 ± 3 kJ mol-1 and 389.5 ± 8 J K-1 mol-1, respectively.
A. Singhal, R. Mishra, S.K. Kulshreshtha, P.V. Bernhardt, E.R.T. Tiekink, Journal of Organometallic Chemistry 691 (2006) 1402-1410

A1092 – Hybrid Nafion-inorganic oxides membrane doped with heteropolyacids for high temperature operation of proton exchange membrane fuel cell

Performance of the proton exchange membrane fuel cell (PEMFC) with composite Nafion-inorganic additives such as silicon oxide (SiO2), titanium dioxide (TiO2), tungsten oxide (WO3), and SiO2/phosphotungstic acid (PWA) has been studied for the operation of temperature of above 100°C. These composite membranes are prepared by the way of blending of the inorganic oxides with Nafion solution by the recasting procedure. The physico-chemical properties studied by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques have proved the uniform and homogeneous distribution of these oxides and the consequent enhancement of crystalline character of these membranes. The thermogravimetry analysis (TGA) results have indicated that the additives TiO2 and WO3 have accelerated decomposition of the membrane at an earlier temperature than that of the Nafion membrane. The modified membranes have shown higher uptake of water relative to that of the unmodified membranes. The proton conductivity of the modified membranes, except that of the Nafion/TiO2, is found to be close to that of the native Nafion membrane at high temperature and at 100% relative humidity (RH), however, it was much higher at low RH. The performance of these modified membranes in the PEMFC operated at 110°C and 70% RH is better than that of Nafion membrane and is found in the order of Nafion/SiO2/PWA > Nafion/SiO2 > Nafion/WO3 > Nafion/TiO2.
Z-G. Shao, H. Xu, M. Li, I-M. Hsing, Solid State Ionics 177 (2006) 779-785

A1091 – Oxygen adsorption properties of YBaCo4O7-type compounds

The oxygen adsorption and desorption of newly found compounds RBaCo4O7 (R = Y, Dy-Lu, In) were investigated by thermogravimetry (TG) in the temperature range from room temperature to 1100°C. The influence of Co replaced by Zn and Fe on the oxygen diffusion properties of YBaCo4O7 was also studied. TG results showed clearly that all RBaCo4O7 compounds basically experience two oxygen adsorption and desorption processes in the temperature range 20-1100°C in oxygen flow. One happens at about 200-450°C and the another happens at about 660-1050°C. The differences between the resulting states by adsorbing oxygen at lower and high temperature were discussed based on the X-ray diffraction (XRD) patterns and TG data. We showed evidence that the oxygen adsorption at the lower temperature has a small activation energy, while the oxygen adsorption at the higher temperature has a large activation energy. The oxygen adsorbed at high temperature will destroy the RBaCo4O7 structure. Zn substituting in the YBaCo(4-x)ZnxO7 influences the oxygen diffusion behavior prominently, the amount of oxygen adsorbed becomes increasingly weak with the increase of Zn content and disappears completely for the samples with x>2.0. However, replacement of Co by Fe has little effect on the oxygen absorption process.
H. Hao, J. Cui, C. Chen, L. Pan, J Hu, X. Hu, Solid State Ionics 177 (2006) 631-637

A1094 – C40E steel oxidation under CO2: Kinetics and reactional mechanism

Between T = 1183 and 1283K and under pure carbon dioxide (10^4 < PCO2 < 10^5 Pa) C40E steel (or 1040) oxidizes following two parallel reactions: decarburization and oxidation of iron, forming the only w¨ustite phase Fe(1-x)O. At the beginning, the weight loss due to the decarburization is predominant and the weight change by surface unit follows a kinetic law ?m/S = -19.3 x P(CO2)^0.20 x exp(-185000/2RT) x t^(1/2) while iron oxidation law is ?m/S = 133 x P(CO2) x exp(-245000/RT) x t. Iron oxidation mechanism is quite the same as that of pure iron, well known in the literature. Both reactions do not interfere quantitatively with each other although wüstite appears simultaneously with decarburization. Oxide scale is well crystallised, porous at the beginning, with a preferential growth of the atomic plane (1 1 1). These results allow to control sharply superficial formation of wüstite on carbon steel pieces, without excessive decarburization of the substrate in order to favor its subsequent coating by thermal plasma route.
S. Valette, A. Denoirjean, D. Tétard, P. Lefort, Journal of Alloys and Compounds 413 (2006) 222-231

A1093 – One-step synthesis of methyl isobutyl ketone from acetone catalysed by Pd supported on Zn(II)-Cr(III) mixed oxide

Pd metal (0.1-1 wt%) supported on Zn(II)-Cr(III) (1:10) mixed oxide was found to be an efficient bifunctional catalyst for the one-step synthesis of methyl isobutyl ketone (MIBK) from acetone and H2 in gas- and liquid-phase processes. The reaction involves the acid-catalysed condensation of acetone to form mesityl oxide, followed by its hydrogenation to MIBK. The gas-phase reaction produces MIBK with a selectivity up to 78% at 40-66% acetone conversion (200-350°C, ambient pressure). Diisobutyl ketone (DIBK) is the main byproduct, with a total MIBK + DIBK selectivity of up to 93%. The catalyst reaches a steady state in ca. 1 h and shows constant activity and selectivity for at least 50 h on stream. The liquid-phase reaction yields MIBK with up to 83% selectivity and total selectivity to MIBK + DIBK up to 9 at 56% acetone conversion (200°C, 5 bar H2 pressure). As a catalyst support, the amorphous Zn-Cr oxide calcined at 300°C provides higher catalytic activity than the crystalline Zn-Cr oxide calcined at 400°C, probably due to the lower surface area of the crystalline oxide. XRD of 0.3-1%Pd/Zn-Cr oxide showed no pattern of Pd metal, indicating a fine dispersion of Pd particles in the catalyst.
E.F. Kozhevnikova, I.V. Kozhevnikov, Journal of Catalysis 238 (2006) 286-292

A1097 – Phase transition and intramolecular hydrogen bonding in nitro derivatives of ortho-hydroxy acetophenones

The crystal structures of two ortho-hydroxy aryl ketones (5-chloro-3-nitro-2-hydroxyacetophenone, 5-methyl-3-nitro-2-hydroxyacetophenone and the complex 5-chloro-3-nitro-2-hydroxyacetophenone with 2-aminobenzoic acid (anthranilic acid)) were determined by X-ray diffraction. The existence of an intramolecular hydrogen bond of enol character between the hydroxyl and acetyl groups was found by the X-ray method. The enol character was also confirmed by DFT (B3LYP/6-31+G(d,p)) calculations. A phase transition was found at 138 K in 5-chloro-3-nitro-2- hydroxyacetophenone. This phase transition was investigated by differential scanning calorimetry (DSC), dilatometry, and the dielectric method. A study of the nitro-group dynamics in the ortho-hydroxy acetophenones was carried out with DFT (B3LYP/6-31+G(d,p)) calculations.
A. Filarowski, A. Kochel, A. Koll, G. Bator, S. Mukherjee, Journal of Molecular Structure 785 (2006) 7-13

A1096 – Synthesis and characterization of a new (2-NH2-6-CH3C5H4N)H2XO4 (X = P, As)

Crystals of 2-amino-6-methylpyridinium dihydrogenmonophosphate (denoted as 2A6MPP) and 2-amino-6-methylpyridinium dihydrogenmonoarsenate (denoted as 2A6MPAs), have been prepared and grown at room temperature. They crystallize with triclinic unit cells and are isotopic. The following unit cell parameters were found, (2-NH2-6-CH3C5H4N)H2PO4: a = 7.5165(6), b = 8.2640(5), c = 8.5674(7) Å , alpha = 64.845(5), beta = 80.156(3), gamma = 85.783(5), Z = 2, V = 474.61(6) Å3; (2-NH2-6- CH3C5H4N)H2AsO4: a = 7.6011(4), b = 8.4261(6), c = 8.7074(6) Å , alpha = 64.228(3), beta = 81.047(4), gamma = 85.972(4), Z = 2, V = 496.09(6) Å3. The common space group is P¯1. We have determined the structure of the phosphate. It exhibits infinite (H2PO4)n n chains. The organic groups (2-NH2-6-CH3C5H4N)+ are anchored between adjacent polyanions through multiple hydrogen bonds. The thermal property of the compound was investigated as well as was the IR property supported by group theoretical analyses.
A. Chtioui, A. Jouini, Materials Research Bulletin 41 (2006) 569-575

A1095 – Carbonate loss from two magnesium-substituted carbonated apatites prepared by different synthesis techniques

This study was aimed at the investigation of the thermal stability of Mg-substituted carbonated apatites over the wide temperature range. Two different apatites were studied, which were prepared by either precipitation from aqueous solution or by solid-liquid interaction. The following methods were employed: FTIR spectroscopy of the condensed gas phase to evaluate the CO and CO2 release with increasing temperature, FTIR of the solid residue after heating, XRD analysis, thermogravimetry and scanning electron microscopy. Decomposition behavior was shown to depend significantly on the synthesis method. Wetsynthesized powders are significantly less thermally stable compared with those prepared by solid-liquid interaction. Intensive release of carbon oxides from the former was observed at 300°C, whereas the latter powder was relatively stable up to temperature about 1000°C.
S.M. Barinov, J.V. Rau, I.V. Fadeeva, S. Nunziante Cesaro, D. Ferro, G. Trionfetti, V.S. Komlev, V.Yu. Bibikov, Materials Research Bulletin 41 (2006) 485-494

A1099 – Effect of water vapor on annealing scale formation on 316 SS

The oxidation behavior of 316 stainless steel (SS) annealed in air containing 0.1 atm water vapor at temperatures ranging from 800 to 1030°C was investigated. A kinetic study of the oxidation was made by employing thermal-gravimetric analysis (TGA). The morphology, composition and structure of the scale were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experimental results showed that significant breakaway oxidation occurred, resulting in substantial weight increase, as the steel was annealed in moist air at temperatures above 950°C. The scaling behavior of 316 SS in wet air at 1030°C could be divided into two stages based on the alteration of the oxidation rate. In each stage, the scale on 316 SS exhibited a different structure and morphology. The complex process of the formation of scale in wet air was discussed and proposed.
S-Y. Cheng, S-L. Kuan, W-T. Tsai, Corrosion Science 48 (2006) 634-649

A1098 – Thermal and structural properties of Ca-rich Montmorillonite mechanically deformed by compaction and shear

This research work reports on the thermal and structural properties of powdered Ca-rich montmorillonite induced by mechanical deformation, which involves simultaneous compression and shear in a controlled thermodynamic environment. X-ray powder diffraction (XRPD), infra-red (FT-IR) and thermal analyses (TG-DTG-DTA) were employed for structural and thermal characterization. Mechanical deformation performed up to 20 h induces significant physical and structural changes to Ca-rich montmorillonite as a function of time, leading to a progressive compaction and agglomeration of particles, reduction of crystallinity and an increase of microstrain, which affects both the tetrahedral and octahedral layers. Thermal analysis of the deformed samples has indicated a loss of structural OH at a temperature which is well below the classical dehydroxylation temperature of the undeformed Ca-rich montmorillonite. This is a consequence of the disordered and defective structure (produced by the mechanical treatment), which requires a lower energy to induce the dehydroxylation of montmorillonite. Also the formation of mullite produced by heating montmorillonite at high temperature is affected by the mechanical treatment. The deformed samples yielded mullite with a faster kinetics at a lower temperature compared to their original counterparts (1155 instead of 1270°C).
F. Dellisanti, V. Minguzzi, G. Valdrè, Applied Clay Science 31 (2006) 282-289

A1100 – Criteria for the formation of protective Al2O3 scales on Fe-Al and Fe-Cr-Al alloys

The conditions for the formation of external alumina scales on binary Fe-Al alloys and the nature of the third-element effect due to chromium additions have been investigated by studying the oxidation at 1000°C in 1 atm O2 of a binary Fe-10 at.% Al alloy (Fe-10Al) and of two ternary Fe-Cr-10 at.% Al alloys containing 5 and 10 at.% chromium (Fe-5Cr-10Al and Fe- 10Cr-10Al, respectively). An Al-rich scale developed initially on Fe-10Al was subsequently replaced by a multi-layered scale containing mixtures of Fe and Al oxides plus a large number of Fe-rich oxide nodules: internal aluminum oxidation was essentially absent from this alloy. Addition of 5 at.% chromium to Fe-10Al did not suppress the formation of nodules, but they were eventually healed by the growth of an alumina layer at their base, resulting in a signifi- cant reduction of the oxidation rate. Finally, the alloy with 10 at.% Cr formed continuous external alumina scales without any Fe-rich nodule. Thus, the addition of sufficient amounts of chromium to Fe-10Al produces a third-element effect as expected. However, the process found in this alloy system does not involve a prevention of the internal oxidation of Al. Instead, it shows a transition from the growth of mixed Fe- and Al-rich external scales directly to an external Al2O3 scale formation. An interpretation of this kind of mechanism involving a third-element is presented along with a prediction of the critical Al contents required to produce the various possible scaling modes on binary Fe-Al alloys.
Z.G. Zhang, F. Gesmundo, P.Y. Hou, Y. Niu, Corrosion Science 48 (2006) 741-765

A1102 – Synthesis and characterization of copolymers based on styrene and partially fluorinated acrylates

Copolymers of styrene and fluorinated acrylate monomers with F-octylalkyl, F(CF2)8(CH2)n' side groups were prepared by free radical polymerization. Thermal behaviour of the resulting polymers was investigated by DSC and TGA. Even if at the macroscopic scale the polymers surfaces are homogeneous and clear, the analysis indicates that all samples exhibit two glass transitions temperatures. This discontinuity may be regarded as an indication for microphase separation of fluorine-rich and polystyrene-rich microphases. Water and hexadecane contact angles measurements show that these polymers are quite surface active in the solid state. Surface and bulk organizations were investigated by XPS analysis. A strong correlation between bulk organization and surface properties of the polymers could be established. Preferential adsorption of fluorinated segments at the material surface were more pronounced than expected in the bulk.
S. Saïdi, F. Guittard, C. Guimon, S. Géribaldi, European Polymer Journal 42 (2006) 702-710

A1101 – Study of free-radical copolymerization of itaconic acid/2-acrylamido-2-methyl-1-propanesulfonic acid and their metal chelates

The monomer reactivity ratios for itaconic acid (IA)/2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in N,Ndimethylformamide solution using the benzoyl peroxide (Bz2O2) as an initiator with different monomer-to-monomer ratios in the feed were investigated by studying the resulting copolymer composition via elemental analysis. Composition results were summarized and various methods were employed to estimate the monomer reactivity ratios including the use of the Error-in Variables-Model method using a computer program, RREVM. The estimates of the reactivity ratios from the EVM method are found to be rIA = 0.4636 and rAMPS = 0.0357. These values suggest that IA is more reactive than AMPS and the copolymer will be richer in IA units. Cu(II) and Ni(II) chelates of the copolymers were prepared and the formation constants of each complex were determined by the mole-ratio method using the UV-vis spectroscopy. UV-vis studies showed that the complex formation tendency increased in the followed order: Cu(II) > Ni(II). The copolymers and their metal chelates were characterized by FT-IR spectra and SEM analysis. Also, thermal stabilities of the copolymers and their metal chelates were investigated using TGA and DSC analysis.
R. Coskun, C. Soykan, A. Delibas, European Polymer Journal 42 (2006) 625-637

A1104 – Soluble PPVs with few structural defects: Synthesis and characterization

A series of 2,5-dialkoxy poly(1,4-phenylenevinylene) derivatives with different alkoxy side-chain lengths were synthesized via a modified Gilch polymerization. Prolonged reaction and additional base treatment at elevated temperature lead to PPVs with very low chlorine content and few structural defects. The polymers were synthesized in satisfactory yields (45-65%) and had number-average molecular weights of 10,000- 14,000. Structural characterization was accomplished by FT-IR, 1H-NMR, 13C-NMR spectroscopy and by elemental analysis. All polymers are amorphous, stable up to 300°C and soluble in both chloroform and tetrahydrofuran. The UV-Vis absorption and emission in the solid state are in the range 496-507 nm and 578-629 nm, respectively. Band gaps calculated from the UV-Vis spectra edge are in the range 2.06-2.11 eV. Lightemitting diodes (LEDs) based on these polymers were fabricated and characterized by current-voltage measurements.
H. Trad, M. Majdoub, J. Davenas, Materials Science and Engineering C 26 (2006) 334 - 339

A1103 – MCM-41 silica modified with copper and iron oxides as catalysts for methanol decomposition

Mixed copper and iron modified MCM-41 mesoporous silica with various Cu/Fe ratio are characterized by N2 physisorption, X-ray diffraction (XRD), transmission electron micrographs (TEM), X-ray photoelectron spectroscopy (XPS), Moessbauer spectroscopy and temperature programmed reduction with hydrogen. Their catalytic properties in methanol decomposition to CO and H2 are investigated and compared with that of the corresponding mono-component materials. The catalytic behaviour of bi-component materials are discussed based on the nature of the catalytic active sites.
T. Tsoncheva, S. Areva, M. Dimitrov, D. Paneva, I. Mitov, M. Linden, C. Minchev, Journal of Molecular Catalysis A: Chemical 246 (2006) 118-127

A1107 – Role of montmorillonite in flame retardancy of ethylene-vinyl acetate copolymer

The effects of non-treated (MMT), organophilic (OMM), and olefin/silicone polymer intercalated (IMM) montmorillonites on the thermal stability of ethylene-vinyl acetate copolymer (EVA) and on the flammability of magnesium hydroxide filled EVA were studied. The influence of various treatments on the delamination of montmorillonites in EVA was detected by rheological measurements and by Raman microscopy. The latter was a unique method for rapid detection of the dispersion also in highly filled EVA. Enhancement of thermo-oxidative stability of EVA and flame-retarded EVA could be observed by thermal analysis in the presence of variously treated montmorillonites. The flame-retardant ef- ficiency of magnesium hydroxide was improved by simultaneous application of MMT and IMM. The increased performance of magnesium hydroxide was explained by the rheological effect of the IMM, catalytic effect of MMT and chemical interactions of montmorillonites with the metal hydroxide.
A. Szép, A. Szabo, N. Toth, P. Anna, G. Marosi, Polymer Degradation and Stability 91 (2006) 593-599

A1106 – Synthesis of phosphorus-based flame retardant systems and their use in an epoxy resin

Methods are proposed to synthesize efficient organophosphorous compounds and combine them with montmorillonite nanoparticles. The chemical-physical structure and mechanism of action of the new systems were studied in epoxy resin. Best results were achieved using the fully phosphorylated calixresorcinarene derivative: the heat release rate peak could be decreased by 61% and the LOI value was increased from 21 to 28. The salt form of additives in case of phosphorylated phloroglucine derivatives was not advantageous in epoxy resin, because the additives could not participate in the crosslinking process effectively due to their inhomogenous distribution in the matrix. The incorporation of the nanoparticles did not create the desired flame retardant effect which can be explained by the increased heat conductivity and lower mobility of the nanoparticles due to the crosslinked structure.
A. Toldy, N. Toth, P. Anna, G. Marosi, Polymer Degradation and Stability 91 (2006) 585-592

A1105 – Grafting of calix[4]arene derivative on activated carbon surface

A new material has been synthesised by reaction between a calix[4]arene amine derivative and an oxidized activated carbon in DMF. Each reactant was characterized by thermogravimetric analysis (TGA) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS). In addition, the BET surface area of activated carbon, oxidized carbon and calixarene-modified carbon, were measured and are equal to 737, 519 and 351 m2/g, respectively. Results show that calixarene is linked to superficial oxygen functional groups through a covalent bond. A percentage of grafted calixarene of the order of 35% have been calculated from the results of elemental analysis.
N. Toumi, I. Bonnamour, J-P. Joly, G. Finqueneisel, L. Retailleau, R. Kalfat, R. Lamartine, Materials Science and Engineering C 26 (2006) 490 - 494

A1110 – Resistance of zinc thermal sprayed coatings on different corrosive environments

Zinc coatings on ferrous substrates are possible to be applied with thermal spraying. In the present work the corrosion behavior of zinc thermal sprayed coatings deposited on low carbon steel St-37 was examined in a simulated marine atmosphere (salt spray chamber-SSC) and in a dry atmosphere at elevated temperature (400°C). The corrosion progress was examined by means of optical microscopy, scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. From this investigation it was deduced that in the SSC the coating is uniformly corroded, while the main corrosion products are hydrated zinc oxides and chlorides. By contrast at 400°C only a thin, compact and continuous film of ZnO is formed on top of the coating, which remains adherent to the ferrous substrate.
G. Vourlias, N. Pistofidis, D. Chaliambalias, K. Chrissafis, El. Pavlidou and G. Stergioudis, Journal of Thermal Analysis and Calorimetry 87 (2007) 401-409

A1109 – Study of a PCM based energy storage system containing Ag nanoparticles

In this paper, organic phase change material (PCM)/Ag nanoparticles composite materials were prepared and characterized for the first time. The effect of Ag nanoparticles on the thermal conductivity of PCM was investigated. 1-tetradecanol (TD) was selected as a PCM. A series of nano-Ag-TD composite materials in aqueous solution were in-situ synthesized and characterized by means of thermal conductivity evaluation method, TG-DSC, IR, XRD and TEM. The results showed that the thermal conductivity of the composite material was enhanced as the loading of Ag nanoparticles increased. The composite materials still had relatively large phase change enthalpy. Their phase change enthalpy could be correlated linearly with the loading of TD, but their phase change temperature was a little bite lower than that of pure TD. The thermal stability of the composite materials was close to that of pure TD. It appeared that there was no strong interaction between the Ag nanoparticles and the TD. Furthermore, the experiment results indicated that the Ag nanoparticles dispersed uniformly in the materials, occurred in the forms of pure metal.
J.L. Zeng, L.X. Sun, F. Xu, Z.C. Tan, Z.H. Zhang, J. Zhang and T. Zhang, Journal of Thermal Analysis and Calorimetry 87 (2007) 369-373

A1108 – Adiabatic calorimetry and thermal analysis on acetaminophen

Molar heat capacities of acetaminophen were precisely measured with a small sample precision automated adiabatic calorimeter over the temperature range from 80 to 330 K. A solid-solid transition at 149.96 K was found from the Cp,m-T curve. The polynomial functions of Cp,m(J K-1 mol-1) vs. T were established on the heat capacity measurements by means of the least square fitting method. Thermal decomposition processes of acetaminophen have been studied by thermogravimetry. And the thermal decomposition kinetics parameters, such as activation energy E, pre-exponential factor A and reaction order n, were calculated by TG-DTG techniques with the Freeman-Carroll method, Kissinger method and Ozawa method. Accordingly the thermal decomposition kinetics equation of acetaminophen is expressed as: dalpha/dt=2.67 x 10^7 x exp(-89630/RT) x (1-alpha)^0.23. The process of fusion has been investigated through DSC. The melting point, molar enthalpy and entropy of fusion are to be (441.89 ± 0.04) K, 26.49 ± 0.44 kJ mol-1 and 59.80 ± 1.01 J K-1 mol-1, respectively.
F. Xu, L. X. Sun, Z. C. Tan, J. G. Liang and T. Zhang, Journal of Thermal Analysis and Calorimetry 83 (2006) 187-191

A1112 – Partial thermal reduction of ammonium paratungstate tetrahydrate : Evolved gas analysis (TG/DTA-MS) and solid state studies (XRD, FTIR)

Thermal decomposition of ammonium paratungstate tetrahydrate, (NH4)10[H2W12O42].4H2O has been followed by simultaneous TG/DTA and online evolved gas analysis (TG/DTA-MS) in flowing 10% H2/Ar directly up to 900°C. Solid intermediate products have been structurally evaluated by FTIR spectroscopy and powder X-ray diffraction (XRD). A previously unexplained exothermic heat effect has been detected at 700-750°C. On the basis of TG/DTA as well as H2O and NH3 evolution curves and XRD patterns, it has been assigned to the formation and crystallization heat of gamma-tungsten-oxide (WO2.72/W18O49) from beta-tungsten-oxide (WO2.9/W20O58) and residual ammonium tungsten bronze.
I.M. Szilagyi, J. Madarasz, F. Hange and G. Pokol, Journal of Thermal Analysis and Calorimetry 88 (2007) 139-144

A1111 – Pyrolysis study of sewage sludge by TG-MS and TG-GC-MS coupled analyses

The pyrolysis of an urban plant sewage sludge carried out under He atmosphere was studied by thermogravimetric-mass spectrometric (TG-MS) and thermogravimetric-gas chromatographic-mass spectrometric (TG-GC-MS) analyses. The sludge was thermally degraded with a heating rate of 10°C min-1 in the 20-1000°C interval; its mass loss is 51.8% up to 600°C and 61.4% up to 1000°C. Gas chromatographic analyses of the gas released during major thermogravimetric events allow the identification of various chemical species. Water, carbon mono- and di-oxide, several hydrocarbons (up to C5, both saturated and unsaturated) were the major detected species. Minor amount of pollutant species, such as cyano-compounds, were also detected. Among the released species hydrocarbons constituted the major fraction (53%), thus suggesting their immediate exploitation as fuel gas. The pyrolysis behaviour of this sample was then compared with other sewage sludge arising from wastewater treatment plants subjected to anaerobic digestion as found in literature data.
M. Ischia, C. Perazzolli, R. Dal Maschio and R. Campostrini, Journal of Thermal Analysis and Calorimetry 87 (2007) 567-574

A1115 – TG-MS characterisation of pig bone in an inert atmosphere

A challenge for forensic examiners is the ageing and characterisation of bone fragments or decomposed skeletal remains. Due to the sensitivity of thermal methods to morphological states, thermal analysis has been selected as a technique which could overcome the difficulties. In this preliminary study, TG-MS was applied to the characterisation of bone fragments derived from the compact bone of pig rib specimens. TG-MS curves were collected by heating bone samples to 1000°C in an argon atmosphere. Under these conditions, both the organic and inorganic phases decomposed, producing a variety of organic fragments and carbon dioxide. Pyrolysis of the organic phase, which is composed predominantly of collagen, occurred resulting in the observation of ion fragments up to 110 amu. Selected fragments were monitored and their observation is discussed in terms of the decomposition of both the collagen phase and the inorganic carbonated hydroxyapatite phase.
A. Onishi, P.S. Thomas, B.H. Stuart, J.P. Guerbois and S. Forbes, Journal of Thermal Analysis and Calorimetry 88 (2007) 405-409

A1114 – TG-MS characterization of the reaction products of cadmium yellow and malachite artist’s pigments

The deleterious interaction of some traditional sulphide artists pigments and copper ions results in the formation of black copper sulphides, in particular, covellite (CuS), and, hence, the discolouration of valuable artworks. In this paper the interaction of malachite, a source of copper(II) ions, with the pigment cadmium yellow, a sulphide pigment comprising of a solid solution of cadmium and zinc sulphides, is investigated by XRD and TG-MS. XRD showed the presence of the copper sulphide and cadmium carbonate phases, produced by a simple ion exchange mechanism. TG-MS showed the complexity of the range of metastable phases produced. The identification of these phases, however, requires further work.
R. White, P.S. Thomas, M.R. Philips, R. Wuhrer and J.P. Guerbois, Journal of Thermal Analysis and Calorimetry 88 (2007) 181-184

A1113 – Influence of preparation conditions on thermal properties of lanthanide benzenepolycarboxylates

Properties of lanthanide 1,2,4-benzenetricarboxylates and lanthanide 1,2,4,5-benzenetetracarboxylates obtained by a classical synthesis method and under hydrothermal conditions were compared. Solid 1,2,4-benzenetricarboxylates and 1,2,4,5-benzenetetracarboxylates of cerium, neodymium and erbium were prepared by a classical precipitation method. The same lanthanide compounds were obtained also from hydrothermal reaction. All obtained products were examined by elemental analysis. General formulae of complexes were: Ln(1,2,4-btc).xH2O and Ln4(1,2,4,5-btec)3.yH2O. The thermal analysis shows that hydrothermal conditions cause the coordination of less number of water molecules to complex molecule. Because lanthanide ions exhibit the most often the coordination number equal 8 or 9 one can conclude that the coordination ability of carboxylic groups under hydrothermal conditions is different from that under mild ones. Probably, in hydrothermal conditions the carboxylic groups of 1,2,4-benzenetricarboxylate ions are able to form more coordination bonds with lanthanide ions than under normal pressure.
M. Iwan, R. Lyszczek, A. Ostasz and Z. Rzaczynska, Journal of Thermal Analysis and Calorimetry 88 (2007) 157-162

A1118 – Thermal, spectral and magnetic behaviour of 4-chloro-2-methoxybenzoates of light lanthanides (III)

4-chloro-2-methoxybenzoates of light lanthanides (III) were obtained as mono-, di- or trihydrates with metal to ligand ratio of 1:3 and general formula Ln(C8H6ClO3)3.nH2O, where n=1 for Ln=Ce, Pr, n=2 for Ln=Nd, Sm, Eu, Gd, and n=3 for Ln=La. The complexes were characterized by elemental analysis, IR spectra, thermogravimetric studies, X-ray diffraction and magnetic measurements. The carboxylate group appears to be a symmetrical bidentate, chemating ligand. All complexes seem polycrystalline compounds. Their thermal stabilities were determined in air. When heated they dehydrate to form anhydrous salts which next are decomposed to the oxides of the respective metals. The solubilities of light lanthanide (III) 4-chloro-2-methoxybenzoates in water at 293K are of the order of 10^(-5) The magnetic moments were determined over the range of 77-300K. They obey the Curie-Weiss law. The values of µeff calculated for all componds are closed to those obtained for Ln3+ by Hund and Van Vleck. The results indicate that there is no influence of the ligand field of 4f electrons on lanthanide ions and the metal ligand bonding is mainly electrostatic in nature.
W. Ferenc, B. Cristovao, J. Sarzynski and M. Wojciechowska, Journal of Thermal Analysis and Calorimetry 88 (2007) 877-883

A1117 – Kinetics of thermal oxidation of titanium carbide and its carbon nano-composites in dry air atmosphere

Results of research work on oxidation of TiC/Cnano-composites in air and under non-isothermal conditions are presented. The oxidation of nano-crystalline titanium carbide as well as its carbon composites were studied using TG-DSC method in dry air atmosphere. The investigated samples were as follows: commercial TiC nano-powders from Alfa Aesar (80nm) and carbon composites including nano-crystalline TiC (30 nm and 50, 10, 3 mass% of carbon in matrix). The measurements were executed in the Setaram thermoanalyser TG-DSC 92-15 in non isothermal conditions, with mass samples of 30 ± 0,2 mg and constant heating rate in the range 2-10K min-1. During the oxidation experiments the heat flux (HF), thermogravimetric and derivative thermogravimetric curves were recorded. Th( g(alpha) functions (kinetic models), kinetic parameters of the Arrhenius equation A and E, dependencies of conversion degree on time were determined. Comparison of oxidation rates of different TiC nanomaterials was made.
A. Biedunkiewicz, N. Gordon, J. Straszko and S. Tamir, Journal of Thermal Analysis and Calorimetry 88 (2007) 717-722