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Volume 41, Issue 11
Displaying 1-24 of 24 articles from this issue
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Lidong Chen, Takashi Goto, Masakazu Mukaida, Masayuki Niino, Toshio Hi ...1994 Volume 41 Issue 11 Pages 1299-1303
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSBoron-rich silicon borides were prepared by solid state reaction and arc-melting using boron and silicon powders. Rhombohedral SiB ?? phase in which n ranged from 15 to 49 was obtained. The lattice parameters, a and c, of SiB ?? increased with increasing Si content. The specimens obtained by arc-melting consisted of Si and SiB ?? . A quick cooling process caused the Si formation. The thermal conductivity, electrical conductivity and Seebeck coefficient of the arc-melted materials were measured. The ZT value increased with temperature, and was about 0.1 at 1200K.View full abstractDownload PDF (261K) -
Takashi Goto, Eiji Ito, Masakazu Mukaida, Toshio Hirai1994 Volume 41 Issue 11 Pages 1304-1307
Published: November 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSSiC-B4C composites were prepared by arc melting in argon atmosphere using SiC and B4C powders. Uniform lamella texture indicating eutectic reaction was observed at mSiC (SiC molar content)= 0.45 to 0.5. The lowest melting temperature (eutectic temperature) was about 2600K. The lattice parameters of SiC and B4C phases were almost in agreement with those of starting powders. The densities of composites nearly agreed with those calculated from the volume content of each phase. The Seebeck coefficients (α) of SiC-B4C composites increased with increasing temperature in the range between 400 and 1200K. The SiC-B4C composite of mSiC=0.4 (near the eutectic composition) showed the greatest α values (e.g.α=750μV/K at 1050K).View full abstractDownload PDF (2485K) -
Shinya Shiga, Kyota Fujimoto, Krishnamurthy Raviprasad, Minoru Umemoto ...1994 Volume 41 Issue 11 Pages 1308-1314
Published: November 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSMechanical Alloying (MA) in Fe-(Mn)-Si-(Al) system with methanol as an agent was performed by using a horizontal ball mill under Argon atmosphere. For the nominal composition of Fe33Si67 and Fe30Si70, ε-FeSi and β-FeSi2 were formed after 1800ks of MA, respectively. The powder milled for 720ks was consolidated by hot pressing (1373K, 1.8ks, 28MPa) and followed by β annealing (1033K, 360ks). The volume fraction of ε phase formed by hot pressing the MA powder is higher than that expected from the equiliblium phase diagram. This is considered to be due to the small molar volume of ε phase compared to those of α and β phase. The temperature dependence of transformon rate from (α+ε) to β was measured using 720ks milled MA powder of Fe30Si70. Two maxima were observed at 1153K and 1033K. The figure of merit, Z=α2/(ρ⋅K), where α: seebeck coefficient, p : specific electrical resistivity, is : thermal conductivity, of MA sample is higher than that prepared from ingot metallurgy (IM). This improvement of Z is caused by the reduction of is L(lattice thermal conductivity). But, ρ is about twice of IM sample. The Al2O3 particles which may form during MA process by the reaction of Al with oxygen in methanol may raise the electrical resistance of MA sample. To improve the thermoelectric properties, it is important use an additive with high electrical conductivity which act to prevent grain growth during sintering.View full abstractDownload PDF (496K) -
Krishnamurthy Raviprasad, Minoru Umemoto, Isao Okane1994 Volume 41 Issue 11 Pages 1315-1319
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSMechanical alloying (MA) is a non-equilibrium processing route for the synthesis of metastable phases. The technique has been widely used for solid state amorphization. It has been observed that the mechanical alloying process can lead to amorphization in systems exhibiting both positive and negative heat of mixing. As the process involves energizing the system, we discuss how the system uses this input energy for the synthesis of metastable phases. The technique is independent of the starting condition of the material being milled, like elemental powders or intermetallic compound. Hence, such an equilibrium which is forced onto the system is termed as "dynamic equilibrium". We also discuss the different forms in which the system can store part of the input energy. Simple calculations have been performed to estimate the individual contributions to the non-chemical energy. The calculations show that the grain boundary energy (-5000 J/mol) is the dominant one. Thus, the system can store maximum energy in the form of grain boundaries with long time milling. This leads to the generation of grain boundaries and results in the refinement of grain size. A model for the grain size refinement has been proposed. The refinement in grain size can be explained as a combination of deformation, fracturing, folding and rotation.View full abstractDownload PDF (277K) -
Kazuhiko Majima, Kenichi Nagai, Shigeru Katsuyama, Hiroshi Nagai1994 Volume 41 Issue 11 Pages 1320-1324
Published: November 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSAmorphous powders with composition (Fe3B)1-X(Nd16Fe78B6)X(0.250≤X≤0.438) were prepared by mechanical alloying (MA) for 30h in Ar. These MA'ed powders were heat treated for crystallization at 873-973K in vacuum, and their magnetic properties were studied in connection with the composition and the heat treatment temperature. The optimum heat treatment temperature was found to be at 893K, where the specimen was composed of the hard magnetic phase of Nd2Fe14B, and the soft magnetic phases of Fe3B and a -Fe. The coercivity increased with increasing Nd concentration, while the saturation magnetization decreased with increasing Nd concentration. The coercivity of 2.80kOe and saturation magnetization of 144emu⋅g-1 were obtained in the 5.0 at% Nd specimen. TEM photograph showed that the grain size of crystallized powders was about 30nm, irrespective of Nd concentration.View full abstractDownload PDF (1881K) -
Kazuhiko Majima, Takashi Umemoto, Shigeru Katsuyama, Yuji Kaneko, Hiro ...1994 Volume 41 Issue 11 Pages 1325-1330
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe preparation of Nd2Fe14B permanent magnetic powder with a fine microstructure has been tried by mechanical grinding (MG) and subsequent heat treatment. The decomposition of Nd2Fe14B phase into α-Fe and an amorphous phase was observed after MG. The powder annealed in vacuum after MG was composed of much finer grains than single magnetic domain size of about 300nm, and its coercivity was as high as 0.76MA/m. On the other hand, the coercivity of the powder annealed in Ar after MG was as low as 0.2MA/m, though it was also composed of much finer grains than single magnetic domain size. And the remarkable increment of oxygen content in the specimen was observed by the heat treatment in Ar. Such a remarkable increment of oxygen content resulted in the existence of large amounts of α-Fe and neodymium oxide. These phases caused the low coercivity. It was also found that MG time influenced the hard magnetic properties. In this work, the best MG time was confirmed to be 72ks.View full abstractDownload PDF (2223K) -
Mikio Ito, Kazuhiko Majima, Shigeru Katsuyama, Hiroshi Nagai1994 Volume 41 Issue 11 Pages 1331-1335
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSSm2Fel7NX permanent magnet was prepared by using Sm2.0-2.5Fe17 alloy powders as the starting material, and the effect of starting composition of alloy powder on nitriding process and magnetic properties was investigated. The alloy powders were subjected to mechanically grinding (MG) in NH3 atmosphere for 10.8ks and subsequent nitriding in N2 gas flow for 3.6-10.8ks at as low temperature as 623K. X in Sm2Fe17NX was confirmed to be about 3 for all of specimens after nitriding for 7 10.8ks. Maximum coercivity, 960kA/m (12.1kOc) was observed for Sm 2.3 specimen after the above nitriding process, and even the Sm=2.0 specimen with stoichiometric composition showed the coercivity higher than 80OkA/m (10kOc).View full abstractDownload PDF (262K) -
Kazuhiko Majima, Katsuhiro Matsukado, Shigeru Katsuyama, Hiroshi Nagai1994 Volume 41 Issue 11 Pages 1336-1340
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe sintering behavior of the compacts composed of Sm2Fe17Nx and 30wt%Zn was studied by DSC, the dilatometric measurement and XRD, and the magnetic properties of the sintered compacts were also investigated by using VSM. The dilatometric measurement revealed that the compacts exhibit an expansion beginning at 643K during sintering, and it was confirmed that this expansion was due to the formation of FeZn4 and/or Fe3Zn7. The results of VSM show that magnetic properties were improved with the increase of heat treatment temperature from 623K ; the optimum coercivity(iHc) of 0.948T was obtained by the heat treatment at 747K for 4h. Beyond 763K, however, the magnetic properties decreased due to the decomposition of Sm2Fe17Nx into α-Fe and SmN.View full abstractDownload PDF (1401K) -
Hideyuki Kuwahara, Jun Takada1994 Volume 41 Issue 11 Pages 1341-1351
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSPlasma nitriding behavior of iron alloys was studied from the view point of material science. The role of nitriding of iron or steels in the field of surface modification was clarified and then the features of plasma nitriding were discussed compared with those of the conventional gas nitriding. The strengthening mechanism of nitriding layer and the kinetics of its growth were discussed on the basis of results of the plasma nitriding of ferritic iron alloys, Fe-Ti and Fe-19Cr alloys. The strengthening of an internal nitriding layer due to dispersion of fine nitride precipitates was interpreted by either the cutting model or by-pass one in dislocation-precipitate interactions. The mechanism depends upon the volume fraction of the pre-cipitates. The growth rate of the nitriding layer was discussed on the basis of nitrogen diffusion in the iron matrix on the analogy of internal oxidation. The plasma nitriding of the austenitic iron alloy brought to make clear the role of plasma. The collision of N2+ ions to the specimen surface prevented the external layer of γ'-Fe4N from forming because of sputtering. And then the exited species in the plasma succeed to react directly with the specimens. This direct reaction caused a remarkable excess amount of nitrogen to dissolve into austenitic iron phase. Finally, an application of plasma nitriding to powder materials was discussed.View full abstractDownload PDF (6214K) -
Katsuaki Suganuma1994 Volume 41 Issue 11 Pages 1352-1360
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThis overviews the interface microstructures in ceramic fibers/whiskers reinforced aluminum alloys and discusses how we can control those interfaces in order to achieve optimized properties for composites. Among many factors influencing on properties of composites, breaking oxide films on aluminum powders, getting interfacial binding and controlling reaction are three of the essentials. For breaking oxide films, alloying elements such as magnesium and silicon have great effects. One should select an optimized alloy for the matrix of a composite. Once surface films are broken and the flesh surfaces of reinforcements and a matrix alloy contact each other, a tight bonding at an interface can be achieved easily because of the high activity of aluminum. One must control the interface reaction. Two interfaces are shown as the examples for controlling interfaces to obtain better properties. Several methods are proposed for the interface control to improve high temperature properties of aluminum matrix composites.View full abstractDownload PDF (7123K) -
Norihiro Itsubo, Koumei Halada, Kazumi Minagawa, Ryoichi Yamamoto1994 Volume 41 Issue 11 Pages 1361-1366
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSAs a direction of material's development for future, we need "Eco-materials" which consider not only characters when we use products, but also environment. A development of method which Eco- materials aims is not utilization of additional elements but changing forms of existence for obtaining good characters. From a point of this view, we paid attention to "SCIFER" which has a recyclable formation of Fe-C-Si-Mn and excellent characters. Still more, we tried to adhere UFP with SCIFER's surface and to investigate effects for manufacturing composites by using it. Results are as follows.
1.In order to ascend sintering power within the region of lower temperatures where SCIFER's minute structures are good, it is necessary to use Ultra Fine Powder.
2. Utilization of solution dispersed UFP made adhereing of UFP with SCIFER's surface possible.
3. Scene parts where UFP united matrix with SCIFER were aquired.View full abstractDownload PDF (5366K) -
Atsushi Nakahira, Koichi Niihara1994 Volume 41 Issue 11 Pages 1367-1372
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe effect of additional phases, mainly metal-boride and metal-nitrides, on the microstructure and some mechanical properties of γ-TiAI(55/45)-based titanium aluminides have been investigated. The considerable changes in the microstructure of γ-TiAl-based titanium aluminides were achieved by the addition of metal-boride and nitrides into γ-TiA1 titanium aluminides. Fine and duplex microstructures of γ-TiAl matrix, in which the lamellar phase was dispersed in the equi-axed γ-TiAI matrix grains, were observed by SEM and TEM. After reaction sintering, formation of Ti2N and Ti2AIN phases and simultaniously Cr, Nb and Zr solid solution into γ-TiAl titanium aluminides were confirmed. Especially, NbN addition inhibited the grain growth of matrix and resulted in the increase in bending strength and hardness at room temperature.View full abstractDownload PDF (5489K) -
Norimasa Umesaki, Nagao Kamijo, Isao Tanaka, Koichi Niihara1994 Volume 41 Issue 11 Pages 1373-1380
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSComputer simulation, using the molecular dynamics (MD) technique, has been carried out on an silicon nitride (a-Si3N4) with simple Busing-type potentials. Furthermore, the local structure of chemical vapor-deposited (CVD) a-Si3N4 has been studied at the Si Kedge by the use of a laboratory XAFS system. From the MD simulation and XAFS results, the short-range structural arrangement of a-Si3N4 comprises tetrahedral SiN4 units. The MD and XAFS results presented in this study also indicate that there exist only a small number defects such as dangling bonds.View full abstractDownload PDF (400K) -
Kohmei Halada, Kazumi Minagawa, Koichi Yagi1994 Volume 41 Issue 11 Pages 1383-1388
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSTo meet the demands of the age when the environmental issue becomes more critical, a new measure to evaluate products from a viewpoint of environmental load is introduced. The measure, which is called LCA (environmental Life Cycle Analysis), gives quantitative evaluation of total environmental load of products from the stage of oremining of raw materials to the stage of disposal after their usage. Sintering materials of JIS standard and various kinds of PM steel were subjected to LCA in this research. Objects of analysis were the consumption of fossil fuel, CO2 emission, SO2 emision. NOx emission and dust emission during overall production stages. LCA presented that each PM materials had individual environmental load. The differences in sevral percentages of additives and that of sintering conditions brought relatively great changes of the environmental load.View full abstractDownload PDF (402K) -
Hironao Tanaka, Kentaro Ohhashi, Yutaka Ishiura1994 Volume 41 Issue 11 Pages 1389-1394
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSSamples with a composition of Bi1.8Pb0.4Sr2Ca2Cu3.2LixOy(x=0 to 0.1) were pressformed at 196MPa and heat-treated at 825 to 850°C for 20h and these steps were repeated 3 times without pulverazation. The highest value of Tc(106K) was obtained for the samples with x=0.01 and 0.05 sintered at 840°C. On the other hand, the highest value of Jc(77K, OT) was obtained for the sample with x=0.01 sintered at 845°C. The values of Tc and Jc were decreased for all samples sintered at 825 and 850°C. The Li-addition promoted the formation of high-Tc phase and gave higher value of Jc and better sinterability.View full abstractDownload PDF (312K) -
Junichi Asami, Masanori Kawahara1994 Volume 41 Issue 11 Pages 1395-1399
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSFor the die compacting of Ti powder, lubricant-mixing and die-wall lubrication were examined. The former was carried out in the addition of zinc stearate to the Ti powder. The lubricant-mixing method was liable to produce adhesion between the die and Ti powder. The latter has been applied two-step pressing which made possible the compacting at high pressure and the preparing of the compacts containing no lubricant. In comparison of two lubrication methods, the die-wall lubrication was found to be effective for improvement of the green strength in spite of lower green density. Moreover, pure Ti sintered compacts could be obtained by this method because of keeping those samples free from contamination of furnace atmosphere with lubricant burn off products.
The characteristics of green and sintered compacts were significantly influenced by the lubrication methods regardless of the lubricant content.View full abstractDownload PDF (2732K) -
Norimitsu Hirose, Junichi Asami1994 Volume 41 Issue 11 Pages 1400-1404
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSA new method for predicting deformation due to sintering of powder compact was suggested: the data of dimensional change map (DC map) and density distribution map for carbonyl nickel green compact of 1 mm thickness measured on an acoustic microscope are employed to calculate the deformation due to sintering. We suggest a new technique to predict deformation by simple computer simulation with these data. To decrease the error in calculation, especially, the influence of the edges of DC map upon this simulation is considered in the computing progress. These results in the calculated outlines of the specimen similar to the shapes of the sintered compacts. DC map, converted from the acoustic image of green compact, thus, includes information of deformation after sintering. It is capable of predicting deformation due to sintering by computer simulation with the DC map for simple shape green compacts.View full abstractDownload PDF (2195K) -
Makoto Nishi, Takaaki Sugita1994 Volume 41 Issue 11 Pages 1405-1411
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe main objective of this study is to evaluate the strength reliability of ceramics with machining damages under cyclic loading. The conceptual algorithm for application of linear fracture mechanics is proposed to the strength reliability evaluation of ceramic component. Also the machining damages in ceramic component are converted by the multiple cracks model with same crack length and crack spacing in order to analyze. The stress intensity factor on the ceramics with multiple cracks under the cyclic loading is discussed in connection with the crack spacing and the crack propagation length with no failure. On the other hand, the fatigue crack growth parameters C and m, and the fatigue fracture toughness value Kfc of ceramic component are calculated from the result of a cyclic four point bending test. Further, statistical characteristics of the C, m and Kfc for the ceramics with multiple cracks are estimated from Weibull distribution function in the ceramics with single crack, which was discussed in the previous paper. This analytical method could be applied to predict the life of ceramics with various machining damages. Two examples of the life of PSZ ceramics with laser and grinding damages are indicated using the analytical method proposed in this paper and by the repeated four point bending test, and then the experimental result has agreed with the analytical result.View full abstractDownload PDF (1591K) -
Analyusis of Crack Propagation Characteristics in Ceramics with Multiple CracksMakoto Nishi, Takaaki Sugita, Yoshinori Funada1994 Volume 41 Issue 11 Pages 1412-1418
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn this paper, the fatigue crack growth characteristics of PSZ ceramics with multiple cracks is described concerning with the number of cracks, crack spacing and crack length. The stress distribution around the crack tips has been analyzed in the case of four point bending test model using the finite element method. It is confirmed that the maximum principal stress value of crack tips decreases with increasing the number of crack and narrowing the crack spacing. Also, the maximum principal stress value of crack tips which lead to fracture is changed by growth of other cracks, which are independent from failure. On the other hand, crack growth rate parameter m, -logC in multiple cracks are calculated from stress intensity factor K, which is analyzed by J-integral around the crack tip. It is found that the estimated life of PSZ ceramics with multiple cracks agrees with the fatigue life which is elucidated from fatigue test.View full abstractDownload PDF (425K) -
A Proposal of Strength Reliability Evaluation Method for Ceramics with Machining DamageMakoto Nishi, Tadaaki Sugita, Yoshinori Funada1994 Volume 41 Issue 11 Pages 1419-1425
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThis paper describes the method for strength reliability evaluation of ceramics with machining damages and the prediction of the life of PSZ ceramics with thermal cracks caused by laser heating. The stress intensity factor of a four point bending model with machining damages is analyzed concerning with the number of cracks and crack density using finite element method. It is necessary to know the interactive interference of cracks within ten times area of each crack length in order to obtain the stress intensity factor of the crack tips which lead to failure. Also the crack growth parameter m and C of PSZ ceramics with the thermal crack damages are calculated from approximate equation of stress intensity factor in the machining damage model. As the result, it is found that the experimental results of fatigue test of the specimen with crack damages caused by laser heating agrees with the life predicted from analysisView full abstractDownload PDF (2583K) -
Tomio Satoh, Kunio Okimoto, Mineo Gonda, Shin-ichi Nishida1994 Volume 41 Issue 11 Pages 1426-1430
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIt is often desired to control the shape and surface morphology of powders as well as the microstructure of powders. A rotating disk atomization method has been used to produce Al-base prealloyed powders with controlled powder shape and microstructure. The characteristics of the powders have been investigated with respect to particle shape, surface morphology, microstructure, hardness and lattice constant of Al phase, α-Al, of the powders.
The surface morphology of the powders is significantly influenced by alloy compositions. Although the shape of high purity Al powder is spherical, the coarse shrinkage cavity exists on the surface. The cavity diminishes by addition of 1wt% Si into the high purity Al. The cooling rates of the powders are estimated to be 105-104 K/s for the particle size less than 100 μm in diameter from the size of the microstructures of Al-33Cu and Al(5N)-1Si pre-alloyed powders. The lattice constant of Al phase, α-Al, decreases and the hardness increases in Al(SN)-1Si pre-alloyed powder as a function of rapid solidification rate. These changes are caused by supersaturation of Si into Al.View full abstractDownload PDF (2775K) -
Tetsuo Kato, Tomio Kono, Makoto Kawamura, Satoru Sakurai1994 Volume 41 Issue 11 Pages 1431-1436
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSInfuluence of adding Al to Fe-13Cr magnetic alloy on the magnetic properties was investigated in the direct and alternating field. With increasing sintering temperature, the coercive force decreases and the magnetic flux density increases in regardless of Al content. Thus the magnetic property in the direct field is improved. This may be due to the increase of the density. Under the alternating field, on the contrary, the amplitude relative permeability decreases at higher frequency with increasing sitering temperature. On the other hand, the magnetic property in the direct magnetic field deteriorates with increasing At content at the fixed sitering temperature. In the alternating field, on the contrary, the amplitude relative permeability unchanges below 2% Al content, but above 3% content the characteristic seems to improved. But the improvement of the magnetic property in the alternating field with Al content as the previous study for the melting alloy. It is presumed as the reason to be not enough to the sintered density.View full abstractDownload PDF (413K) -
Yuji Muramatsu, Tsuneo Ohkoshi, Hiroo Suga1994 Volume 41 Issue 11 Pages 1437-1443
Published: November 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSTiAl intermetallic compounds containing Cr were prepared by sintering mixed powder compacts of TiH2. TiAl3, and Ti-55Al-15Cr(mass%) alloy. The sintered compounds produced were subjected to hot isostatic pressing (HIPing) at 1470K and 202MPa for 3.6ks without canning. The densification by Wing was examined as functions of Cr content, sintering temperature and sintered density. The microstructure of HIPed TiAl was also examined.
Experimental results showed that the addition of Cr definitely influenced HlPing, and that the densification tended to be more difficult with increased Cr content. However, full densification was achieved when Cr contents were less than 4 at% for 45 at% Al alloys. HIPed density increased with increased sintering temperature, and became saturated when the relative sintered density exceeded 92%. The microstructure of HIPed Ti-45Al-3Cr(at%) alloy consisted of a and γ phases together with β phase. The amount of the β phase increased with increased Cr content and decreased Al content.View full abstractDownload PDF (4858K) -
Shigeru Katsuyama, Yoshiyuki Tanaka, Kazuhiko Majima, Hiroshi Nagai1994 Volume 41 Issue 11 Pages 1444-1447
Published: November 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSThe effect of substitution for La by Ba on the thermoelectric property of rare earth chalcogenide La3S4 was examined. Cubic γ-phase (Th3P4-type) was obtained in the range of 0≤y≤1 in La3-yBayS4. The lattice parameter (a), electrical resistivity (r) and thermoelectric power (α) of La3-yBayS4 increase with an increase of Ba content y. Power factor α2/r shows a maximum value at y=0.6. It seems that there is the most suitable value of y for the power factor.View full abstractDownload PDF (206K)
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