ホーム > 応用例集 > 文献集

文献集

文献を検索

Results 361 to 380 of 5628 articles

Pages
-10 page 18 19 . 20 . 21 . 22 . 23 . 24 . 25 . 26 . 27 . 28 . 29 . 30 . 31 . 32 . 33 . 34 . 35 . 36 . 37 . 38 . 39 . page 20 +10


E0313 - Experimental investigation of the Cu-Si phase diagram at x(Cu)>0.72

Cu-Si phase equilibria have been investigated at compositions greater than 72 at.% Cu by X-ray diffraction, optical and electronic microscopy, electron probe microanalysis and differential thermal analysis. The general aspects of the phase equilibria already reported in literature have been substantially confirmed, but selected composition ranges and the nature of a few invariant equilibria have been modified. In particular stability ranges of the ?, ? and ? phases have been slightly modified as well as temperature and nature of the invariant equilibria related to the ? ? ? transformation. Stability of the ?-(Cu15Si4) phase has been especially investigated concluding that it is thermodynamically stable but kinetically inhibited by nucleation difficulties which become especially effective when samples are synthesized in very high purity conditions. Crystal structure and composition ranges of the high temperature ? and ? phases, despite difficulties by the non-quenchability of these phases, have been investigated by different methods including high temperature XRD.


Katarzyna Sufryd, Norbert Ponweiser, Paola Riani, Klaus W. Richter, Gabriele Cacciamani, Intermetallics 19 (2011) 1479-1488

E0312 - Microstructures and mechanical properties of Fe-Al-Ta alloys with strengthening Laves phase

The addition of Ta to Fe-Al alloys results in the formation of a stable Ta(Fe,Al)2 Laves phase with hexagonal C14 structure in the Fe-Al phase at temperatures of 800, 1000 and 1150 °C. It was found that the solubility of Ta in Fe-Al is generally low and the solubility of Ta varies with Al content. Respective isothermal sections of the Fe-Al-Ta system have been established. Particular attention has been given to precipitation in the Fe3Al phase with a small addition of Ta. At intermediate temperatures, 600-750 °C, an additional Heusler-type phase with L21-structure precipitates, which transforms at longer times and high temperatures to the stable C14 Laves phase. The yield stress in compression and the creep behaviour of the Fe-Al-Ta alloys with various microstructures were studied. Due to the presence of the L21-Heusler phase, the yield stress and the creep resistance at temperatures below 700 °C was increased considerably


D.D. Risanti, G. Sauthoff, Intermetallics 19 (2011) 1727-1736

E0311 - Phase equilibria in the Al-Mo-Si system

The ternary Al-Mo-Si phase diagram was investigated by a combination of optical microscopy, powder X-ray diffraction (XRD), differential thermal analysis (DTA), electron probe microanalysis (EPMA) and scanning electron microscopy (SEM). Ternary phase equilibria were investigated within two isothermal sections at 600 °C for the Mo-poor part and 1400 °C for the Mo-rich part of the phase diagram. The solubility ranges of several phases including MoSi2 (C11b) as well as Mo(Si,Al)2 with C40 and C54 structure were determined. The binary high temperature phase Al4Mo was found to be stabilized at 600 °C by addition of Si. DTA was used to identify 9 invariant reactions and thus constructing a ternary reaction scheme (Scheil diagram) in the whole composition range. A liquidus surface projection was constructed on basis of the reaction scheme in combination with data for primary crystallization from as-cast samples determined by SEM measurements.


Norbert Ponweiser, Werner Paschinger, Anna Ritscher, Julius C. Schuster, Klaus W. Richter, Intermetallics 19 (2011) 409-418

E0310 - Re-investigation of phase equilibria in the system Al-Cu and structural analysis of the high-temperature phase ?1-Al(1 ?)Cu

The phase equilibria and reaction temperatures in the system Al-Cu were re-investigated by a combination of optical microscopy, powder X-ray diffraction (XRD) at ambient and elevated temperature, differential thermal analysis (DTA) and scanning electron microscopy (SEM). A full description of the phase diagram is given. The phase equilibria and invariant reactions in the Cu-poor part of the phase diagram could be confirmed. The Cu-rich part shows some differences in phase equilibria and invariant reactions compared to the known phase diagram. A two phase field was found between the high temperature phase ?1 and the low temperature phase ?2 thus indicating a first order transition. In the ?1/?2 region of the phase diagram recent findings on the thermal stability could be widely confirmed. Contrary to previous results, the two phase field between ? and ?1 is very narrow. The results of the current work indicate the absence of the high temperature ?0 phase as well as the absence of a two phase field between ?1 and ?0 suggesting a higher order transition between ?1 and ?0. The structure of ?0 (I-43m, Cu5Zn8-type) was confirmed by means of high-temperature XRD. Powder XRD was also used to determine the structure of the high temperature phase ?1-Al1??Cu. The phase is orthorhombic (space group Cmmm) and the lattice parameters are a = 4.1450(1) Å, b = 12.3004(4) Å and c = 8.720(1) Å; atomic coordinates are given.


Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Intermetallics 19 (2011) 1737-1746

E0309 - Enhancement of cells proliferation and control of bioactivity of strontium doped glass

Bioactivity and chemical reactivity of bioactive glass offer the ability to bond for soft and hard biological tissues. In this work, synthesis was carried out by using melting and rapid quenching. Strontium was introduced as trace element at different contents in the glass matrix, according to its concentration in the bone matrix. This chemical element presents a high interest in the bone metabolism activity. Investigations were conducted on the surface of biomaterials by using in vitro assay after immersion in SBF. Several physico-chemical methods such as SEM, FTIR, NMR, ICP-OES and MTT test were employed to highlight the effects of the Sr. The in vitro experiments showed that after soaking in SBF, the behaviour of pure glass is different compared to glass doped with Sr. NMR analyses showed in the 29Si MAS-NMR that glass matrix undergoes some changes after in vitro assays particularly the emergence of new components attributed to Q3(OH). The presence of Sr slowed down the bioactivity of glass after immersion in SBF. The non toxic character of compounds was confirmed. Introduction of Sr at 0.1 wt % induce an enhancement of cells at about 14.3%.


H. Oudadesse, E. Dietrich, X.V. Bui, Y. Le Gal, P. Pellen, G. Cathelineau, Applied Surface Science 257 (2011) 8587- 8593

E0308 - Constitutional and microstructural investigation of the pseudobinary NiAl-W system

Pseudobinary NiAl-W section in the range 0.7-1.8 at% was characterised regarding solidification microstructure and constitution. The existence of eutectic reaction was confirmed and occurs at temperature of 1664 ± 2 °C and the composition of 1.5 at% W. As-cast microstructures indicated that the NiAl-W system is an anomalous eutectic with skewed coupled zone and that the NiAl phase is a preferential phase for eutectic nucleation. Directionally solidified alloy containing 1.5 at% W exhibited entirely eutectic structure characterised by eutectic cells with the average value of 500 ?m, interfibre spacing 3.5 ?m, fibre diameter 300 nm, and volume fraction of the W phase 1.4%. The solubility of W in the intermetallic phase is <0.04 at% and the solubility of Ni and Al in the W phase is negligible. Crystallographic orientation between the constituent phases was established to be cube on cube. Based on the results obtained by DTA, microstructural and compositional analysis, a new isoplethal section NiAl-W of the ternary Al-Ni-W system has been proposed.


Srdjan Milenkovic, André Schneider, Georg Frommeyer, Intermetallics 19 (2011) 342-349

E0307 - Phase equilibria in the AleSieV system: The vanadium rich part

The V-rich part of the Al-Si-V phase diagram was determined by a combination of optical microscopy, powder X-ray diffraction (XRD), differential thermal analysis (DTA) and electron probe microanalysis (EPMA). Phase equilibria were investigated at two isothermal sections at 850 and 1300 °C. High temperature DTA was performed to identify the ternary invariant reactions yielding a ternary reaction scheme and the vertical section at 50 at.% V. As cast samples were investigated in order to gain additional information about primary crystallization fields. A liquidus surface projection was constructed for the entire ternary system by combining our experimental data with those from literature.


Beatrix Huber, Klaus W. Richter, Intermetallics 19 (2011) 369-375

E0306 - Influence of strontium on structure, sintering and biodegradation behaviour of CaO-MgO-SrO-SiO2-P2O5-CaF2 glasses

The present study investigates the influence of SrO on structure, apatite-forming ability, physico-chemical degradation and sintering behaviour of melt-quenched bioactive glasses with the composition (mol.%): (36.07 ? x) CaO-xSrO-19.24MgO-5.61P2O5-38.49SiO2-0.59CaF2, where x varies between 0 and 10. The detailed structural analysis of the glasses is made by infrared spectroscopy and magic angle spinning-nuclear magnetic resonance spectroscopy. Silicon is predominantly present as Q2 (Si) species, while phosphorus is found as orthophosphate in all the investigated glasses. The apatite-forming ability of glasses is investigated by immersion of glass powders in simulated body fluid for time durations varying between 1 h and 7 days. While increasing the Sr2+/Ca2+ ratio in the glasses does not affect their structure significantly, their apatite-forming ability is decreased considerably. Further, physico-chemical degradation of glasses is studied in accordance with ISO 10993-14 "Biological evaluation of medical devices - Part 14: Identification and quantification of degradation products from ceramics" in Tris-HCl and citric acid buffer, and the possible implications of the ion release profiles from the glasses in different solutions are discussed. The addition of strontium to the glasses leads to a sevenfold decrease in chemical degradation of glasses in Tris-HCl. The sintering of glass powders renders glass ceramics (GCs) with varying degrees of crystallinity and good flexural strength (98-131 MPa), where the mechanical properties depend on the nature and amount of crystalline phases present in the GCs.


Ashutosh Goel, Raghu Raman Rajagopal, José M.F. Ferreira, Acta Biomaterialia 7 (2011) 4071-4080

E0305 - Size ratio induced yttrium aluminum garnet formation characteristics in nano-scaled Y2O3-Al2O3 powder systems via fast firing processes

The formation characteristics of YAG phase synthesized by fast-firing Y2O3 and Al2O3 powder mixtures were examined. Y2O3 powders of 100, 350, and 500 nm in D50 were mixed with ?-Al2O3 powder of (D50) 200 nm to obtain starting powders denoted as S0.5, S1.75, and S2.5, respectively. In these mixtures, the two oxides contacted wholly with each other but varied in number of contact points and diffusion length. This study aimed to eliminate the YAM and YAP phases, which normally occur during YAG formation. Examinations were conducted using pressed compacts (bulk density of 0.91 g cm?3) prepared with the three mixtures. After pre-heating at 700 °C for 30 s, the compacts were plunged at temperatures of 1050-1450 °C for 5-60 s and then quenched to room temperature. In the S0.5 system, one-step YAG formation occurred by an interface-controlled mechanism, and intermediates were apparently suppressed. However, YAG formation was divided into two stages in the S1.75 and S2.5 systems. Two stages were defined by the heating duration prior to and after 20 s. The interface-controlled mechanism was dominant in the initial stage, and then the diffusion-controlled mechanism was dominant in the second stage, in which YAG formed sluggishly and substantial amounts of YAM and YAP persisted. However, both stages followed the conversion sequence of YAM to YAP and then to YAG. Accordingly, two YAG formation routes derived from reacted Y2O3 of different sizes are proposed. Finally, a pure YAG phase could be obtained by calcining the S0.5 system at 1200 °C for 60 s.


Chen-Tsung Hung, Chai-Yuan Lai, Fu-Su Yen, Materials Chemistry and Physics 129 (2011) 534- 539

E0304 - Carburization of W- and Re-rich Ni-based alloys in impure helium at 1000 C

The surface and microstructure stability of experimental W- and Re-rich Ni-based alloys in an impure-helium environment containing only CO and CO2 as impurities (ppm level) have been investigated at 1000 °C. All the alloys carburized during 50 h of exposure, and, depending on the alloy composition, different carbides of the type M6C, M7C3 and M23C6 formed on the alloy surface, in grain interiors and at grain boundaries. Microprobe analysis and Calphad-based calculations indicated that the chromium carbides (particularly Cr23C6) were enriched by rhenium. Extended exposure (225 h) led to the disappearance of surface transient carbides and the growth of surface oxide Cr2O3 occurred.


Raghavendra R. Adharapurapu, Deepak Kumar, Jun Zhu, Tresa M. Pollock, Corrosion Science 53 (2011) 388-398

E0303 - The effect of P2O5 on the structure, sintering and sealing properties of barium calcium aluminum boro-silicate (BCABS) glasses

The effect of P2O5 incorporation on the sintering, flow and crystallization characteristics of BCABS glasses of composition (mol%) 35BaO-15CaO-5Al2O3-(37 ? x)SiO2-8B2O3-xP2O5 (0 ? x ?5) is investigated. It is observed that addition of P2O5, removes cations (Ba2+ and Ca2+) from the silicate network, resulting in an increase in polymerization. This is reflected by a reduction in TEC and an increase in sealing temperature. In addition, the removal of cations for charge compensation causes a change in major crystalline phases formed, from BaSiO3 to Ba(Al2Si2O8). In addition, beyond 3 mol% P2O5, crystallization of phosphate phases is evident. Based upon the flow temperature, glasses with 0, 1 and 2 mol% P2O5 are selected for sealing. In these glasses, conversion of Cr to Cr2O3 is observed, yielding improved adhesion. However, the 2 mol% P2O5 glass showed an increased crystallization tendency, resulting in incomplete sintering. Therefore, 1 mol% P2O5 seems a good compromise for sealing with improved adhesion


A. Ananthanarayanan, G.P. Kothiyal, L. Montagne, G. Tricot, B. Revel, Materials Chemistry and Physics 130 (2011) 880- 889

E0302 - Is Tl2Ni3S2 a mixed valent compound? Crystal and electronic structure investigations

The crystal and electronic structure of Tl2Ni3S2 is investigated by X-ray structure determination and DFT calculations. The question of charges and possible mixed valences of two different Tl positions in Tl2Ni3S2 is discussed with respect to crystal and electronic structure arguments. Crystal structure parameters were redetermined from single crystal data. A relation is given to typical Tl states in reference compounds like mixed valent Tl2S2, high-pressure TlS, LiTl, and ThCr2Si2 type TlNi2S2. This allows for a comparison of different Tl sites with respect to atomic distances, coordinations, valence, charge, and bonding as well as charge redistribution within layered Ni-S substructures. Complementary methods of charge determination from theory are applied as orbital analysis from precise full potential calculations and charge density analysis by zero flux surface integration according to the AIM theory.


F. Bachhuber, I. Anusca, J. Rothballer, F. Pielnhofer, P. Peter, R. Weihrich, Solid State Sciences 13 (2011) 337-343

E0301 - Compositional effects on the properties of high nitrogen content alkaline-earth silicon oxynitride glasses, AE = Mg, Ca, Sr, Ba

A series of alkaline-earth element containing high nitrogen content oxynitride glasses (AESiON), with AE = Mg, Ca, Sr, Ba, were prepared in order to investigate the compositional effects on the physical properties of the alkaline-earth element. The physical properties were found to change linearly with the concentration of AE elements. The density of the glasses increases substantially with an increase in the AE atomic mass and slightly with an increase in nitrogen ratio. Ba containing glasses shows the value of density 4.16 g/cm3. Glass transition temperatures are found to be higher for Mg glasses, ca. 1020 °C, in comparison with Ba glasses, ca. 895 °C. The hardness of Mg containing glasses shows high values, up to 12.2 GPa and decreases for Ca, Sr and Ba containing glasses. Ba, containing glasses shows high values of refractive index in comparison with the Sr, Ca and Mg containing glasses.


Sharafat Ali, Bo Jonson, Journal of the European Ceramic Society 31 (2011) 611-618

E0300 - Self-flux growth of large EuCu2Si2 single crystals

Large single crystals of the EuCu2Si2 intermetallic compound have been successfully grown by a high pressure vertical floating zone method with optical heating. The suppression of evaporation of volatile elements and control of the floating zone temperature are the key factors for the stability of the growth process. A low travelling velocity of 3 mm/h and a short length of the floating zone play an important role in phase selection and formation of a EuCu2Si2 single crystal. Measurements of oriented single crystalline EuCu2Si2 samples reveal a non-linear temperature dependence of the magnetic susceptibility attributed to the valence fluctuations in Eu ion. But no magnetic ordering transition occurs at T>2 K. The magnetic susceptibility data display significant anisotropy with a magnetic easy c-axis ([0 0 1]). In contrast to the magnetic susceptibility, the anisotropy in the electrical resistivity for the two different crystallographic orientations is less significant.


Chongde Cao, Wolfgang Löser, Günter Behr, Rüdiger Klingeler, Norman Leps, Hartmut Vinzelberg, Bernd Büchner, Journal ofCrystal Growth 318(2011)1043-1047

E0299 - New types of lead-free solders on the base of tin and their properties

The aim of the work is an experimental study of binary, ternary and quaternary systems on the base of tin alloys. 22 alloys with different ratios of individual elements Ag, Cu, In, Sb, Bi, and Sn were prepared experimentally. In addition, 6 alloys of lead-free solders produced commercially (Kovohut? P?íbram nástupnická, a.s.) were used and the Pb-Sn solder served as a comparative etalon. The following characteristics were studied: temperatures and enthalpies of phase transformations (DTA, TG, DSC) of individual solders at the rates of re-heating and cooling of specimens of about 4?Cmin?1, microstructural analysis (optical metallography) and microhardness of specimens, chemical analysis, microanalysis of individual phases in the structure of solders (WDX, EDX), measurement of surface tension and density of solders in dependence on the temperature, test of wettability with or without use of fluxes, measurement of corrosion properties, measurement of electrical resistivity


J. Drápala, R. Kozelková, R. Burkovi?, B. Smetana, R. Dudek, S. Lasek, J. Urbánek, K. Duek, M. Hájek, Kovove Mater. 47, 2009, 283-293

E0298 - Study of physical and mechanical applications on ceramics of the lateritic and alluvial clayey mixtures of the Yaoundé region (Cameroon)

Ceramic products were prepared by mixing lateritic and alluvial clayey materials of Yaoundé (Cameroon) in the humid tropical region, with 20, 50 and 80 wt.% of alluvial clay respectively in lateritic clay. Samples were grounded and sieved and powders obtained were shaped by uniaxial pressing of wet granules and fired under low temperatures between 350 and 1050 °C. Open porosity, bulk density and flexural strength were the principal properties characterised. Results indicates that a maximum of 80 wt.% of alluvial clayey material must be added to lateritic clays of Yaoundé, to obtain weakly porous ceramics and to attain the bulk density ranging from 1.56 to 1.97 g/m3 and a flexural strength of 6-19.85 MPa would be equivalent alluvial clay ceramics. But ceramics with lesser amount of alluvial clayey materials also have interesting flexural strengths in the range of 5-16 MPa, thus higher than porous lateritic clay ceramics.


G.F. Ngon Ngon, R. Yongue Fouateu, G.L. Lecomte Nana, D.L. Bitom, P. Bilong, G. Lecomte, Construction and Building Materials 31 (2012) 294-299

E0297 - Characteristic free volume change of bulk metallic glasses

The free volume change ?Vf(T) of bulk metallic glasses (BMGs) relative to a hypothesized amorphous reference state was measured using the thermal dilatation method. The characteristic free volume change, i.e., the free volume released in structural relaxation ?Vf-sr, was identified quantitatively from the ?Vf(T) curve. For a Fe-based BMG, it was found that ?Vf-sr increases with decreases in the sample diameter and heating rate. ?Vf-sr measured under the same sample diameter and heating rate conditions allowed the convenient comparison of different BMGs. The comparison revealed that the glass-forming ability (GFA) enhancement of each of two Pd-, Mg-, Cu-, Zr-, Ti-, and Fe-based BMGs can be sensitively reflected in the decrease in ?Vf-sr and the narrowing of the difference between the peak temperature of the thermal expansion coefficient and the end temperature of the glass transition process. In addition, for these twelve typical BMGs, there is a good linear relationship between ?Vf-sr and LogDc2 or LogDc, where Dc is the critical diameter. ?Vf-sr is thus sensitive to and has a close correlation with GFA. Furthermore, the ?Vf-sr measurement results are in good agreement with the free volume change measured with the specific heat capacity, room temperature density, and positron annihilation lifetime methods. In the study of the relationship between the structure and properties of BMGs, ?Vf-sr thus plays an important role given its comparability and convenience.


Qiang Hu, Xie-Rong Zeng, M. W. Fu, J. Appl. Phys. 111, 083523 (2012)

E0296 - Microstructure, geotechnical and mechanical characteristics of quicklime-lateritic gravels mixtures used in road construction

Microstructure of quicklime-lateritic gravels mixes, containing up to 8 wt.% quicklime, was investigated by using X-ray diffraction, infrared spectrometry, differential thermal analysis, scanning electron microscopy and energy dispersive spectrometry. Geotechnical and mechanical properties of the mixtures were also measured. Quicklime additions resulted of reduction of clayey fraction, plasticity index, methylene blue value and maximum dry density and the increasing of optimum moisture content. The results showed also that quicklime admixtures resulted in the formation of calcium silicate hydrate type I (C-S-H (I)), portlandite and calcite. This CSH (I) was formed through the pozzolanic reaction between a part of the kaolinite and hydrated lime in the basic medium. Moreover, C-S-H (I) marked crystallization with curing time and observed for the quicklime amounts (?3 wt.%), contributed to the improvement of mechanical properties. These lime modified lateritic gravels are convenient for base course in road geotechnical applications.


Younoussa Millogo, Jean-Claude Morel, Karfa Traoré, Raguilnaba Ouedraogo, Construction and Building Materials 26 (2012) 663-669

E0295 - Phase equilibria in the system NaAl(WO4)2-NaCr(WO4)2

The phase equilibria in the system NaAl(WO4)2-NaCr(WO4)2 are investigated. Nanopowders are synthesized in the whole concentration region from NaAl(WO4)2 to NaCr(WO4)2 by a co-precipitation method. Using X-ray, DTA, TEM and SEM analyses, three concentration regions in the system are established: single-phase region of NaAl1??Cr?(WO4)2 solid solutions (x is between 0 and 0.08), with monoclinic structure, space group C2/c; single-phase region of NaAl1??Cr?(WO4)2 solid solutions (x is between 0.40 and 1.0) with monoclinic structure, space group P2/c; and two-phase region, where the above mentioned phases crystallize simultaneously (x is between 0.08 and 0.40). The thermal behaviour of the two pure boundary phases, as well as the influence of chromium on the thermal stability and the structural characteristics of the solid solutions are discussed.


I. Koseva, A. Yordanova, D. Rabadjieva, P. Tzvetkov, V. Nikolov, Materials Research Bulletin 47 (2012) 3580-3585

E0294 - Nanosized pure and Cr doped Al2?xInx(WO4)3 solid solutions

For a first time are synthesized nanosized solid solutions with formula Al2?xInxCry(WO4)2 (x = 0-2, y = 0.02-0.1). Co-precipitation method is used for the synthesis. It is established that only by strict maintenance of pH between 2.7 and 2.9 a pure, monophase product of In2(WO4)3 can be obtained. By X-ray powder diffraction and DTA/TG analyses, it is established that at room temperature the solid solutions Al2?xInx(WO4)2 at x value between 0 and 1.1 are orthorhombic and for x value between 1.1 and 2.0 are monoclinic. The phase transition temperatures are defined for different x values. Results from X-ray and TEM analyses show that nanosized pure Al2?xInx(WO4)2 and Cr-doped Al2?xInxCry(WO4)2 with size dimension between 10 and 40 nm can be successfully synthesized by co-precipitation method with subsequent thermal treatment at relatively low temperature (550 °C) for 1 h.


I. Koseva, A. Yordanova, P. Tzvetkov, V. Nikolov, D. Nihtianova, Materials Chemistry and Physics 132 (2012) 808- 814


Pages
-10 page 18 19 . 20 . 21 . 22 . 23 . 24 . 25 . 26 . 27 . 28 . 29 . 30 . 31 . 32 . 33 . 34 . 35 . 36 . 37 . 38 . 39 . page 20 +10
>Inscription
For full access to application library, spare parts catalog and newsletters :
>> Inscription
Already registered ?
>> Login
>お問合せ
>> 次のステップ