粉体および粉末冶金
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
52 巻, 10 号
October
選択された号の論文の14件中1~14を表示しています
研究
研究速報
研究
  • 出井 裕, 金原 壮, 岡野 道治
    2005 年 52 巻 10 号 p. 722-729
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    This study was undertaken to investigate the effect of spark plasma sintering (SPS) on the tensile and fatigue properties of laminates of SCS-6 SiC fiber-reinforced Ti-6Al-4V titanium matrix composites (TMC). The Ti-6Al-4V matrix and SCS-6 fiber mat were consolidated by spark plasma sintering at the temperature of 800, 900, and 1000°C and at the pressures of 30 and 60 MPa in vacuum. Tensile specimens of TMC were tested at room temperature, 400, 600, and 800°C. In addition, tensile properties of TMC were experimentally evaluated with 11 to 33% volume fraction of SCS-6. Fatigue tests of TMC were carried out at room temperature and 600°C. Specimens were examined after tensile and fatigue tests using SEM to characterize the fracture surface morphology. The fiber/matrix interactions were analyzed by energy dispersive x-ray spectroscopy (EDS).
    TMC consolidated at 900°C and 60 MPa showed the highest strengths of 857 to 1679 MPa from room temperature to 800°C. The tensile strengths of TMC with volume fraction of fiber varied from 11 to 27% are approximately equal to the theoretical obtained from the rule-of-mixture model. TMC can sustain tensile stress level at or below 450 MPa at 600°C without fracture after more than 107 cycles.
  • 野末 章浩, 朴 容浩, 橋本 等, 川崎 亮
    2005 年 52 巻 10 号 p. 730-734
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    Mechanical alloying followed by pulse discharge sintering (MA-PDS) was employed to synthesize the bulk (Bi,Sb)2Te3 thermoelectric materials with P, Ag or both additions. The effect of P and Ag on the microstructure and thermoelectric performance of the compacts were investigated. The dispersed P particles are found to decrease the size of (Bi,Sb)2Te3 crystallites and inhibit the densification of the alloyed powders, while the added Ag is effective in raising electrical conductivity. On the contrary, addition of P in combination with Ag does not generate a favorable thermoelectric properties.
  • 菅野 光輝, 武田 義信, ベルクマーク アンダース, リンドクヴィスト ビヨン, 植田 義久, 神田 輝一
    2005 年 52 巻 10 号 p. 735-743
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    In order to expand PM business, the improvement of dynamic mechanical properties and the repertory of such data are necessary. We have thought for long time that partially diffusion bonded alloy is more suitable to achieve higher fatigue strength. It is true for the component under some process conditions. However, the level of density for PM components is improving today. The combination of both high density and optimization of secondary operations showed that pre-alloyed material was more suitable to achieve much higher fatigue strength than partially diffusion bonded alloy. Then some studies to improve fatigue strength were presented.
    This paper introduces the improvement of fatigue strength by applying shot peening process and discusses the mechanism of improvement of fatigue strength by considering stress profile. The influence of geometry on stress profile has also been discussed, including the FEM analysis of actual transmission gear to describe the optimum secondary operations for each component.
    The possibility to apply PM components for an actual transmission gear has been discussed in this paper by calculating safety factor with the root stresses measured of the embedded gear in an actual transmission gear box.
特集 HIP/CIP および関連技術
総報
研究
  • 下埜 勝, 大高 理
    2005 年 52 巻 10 号 p. 747-752
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    Diamond grains of various sizes and also the mixed powders of diamond and Si made up in various proportions in different proportions were prepared as the starting materials for synthesis experiments. Respective material was charged in a capsule consisted of Si and SiC and HIPed at 1450°C and 200 MPa for 30 min. After the capsule was removed by mechanical and chemical treatments, their physical properties were measured. By comparison of the density and the bulk modulus, the sample whose starting material was diamond of 12 μm without additive showed the best values. These values were close to those of the material obtained by means of the solid compression of diamond and SiC (ADC). Microscopic observation and XRD revealed that the obtained samples was a sintered compound of diamond and SiC whose hardness was comparable to that of ADC.
    The compound was used to make high-pressure anvils. The prepared test anvils were strong enough to generate high pressures and temperatures up to 17 GPa and 700°C. The transparency to X-ray is another advantage of this anvil. Its further use is expected in high pressure research such as in situ observations of physical properties under compression.
  • 岸本 昭, 岡田 泰行, 牟田口 大輔, 林 秀考
    2005 年 52 巻 10 号 p. 753-756
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    Evaluation samples of p-type α-silicon carbide ceramics were first fabricated by glass capsule HIP method using powder mixture of silicon carbide with boron, aluminum, or gallium at various ratios. The resultant p-type silicon carbide ceramics were doped with nitrogen by changing the post-HIP nitrogen gas pressure. The lattice parameter decreased with nitrogen doping pressure indicating that the incorporated nitrogen were dissolved into silicon carbide. In the case of boron and aluminum doped samples, the piezoresistive coefficient decreased with the nitrogen doping pressure, while gallium doped one remained almost constant with doping pressure.
  • 桜井 利隆, 宮本 欽生
    2005 年 52 巻 10 号 p. 757-762
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    The reaction temperature in the combustion synthesis of AlN was controlled by adding H2 gas to the reactant N2 gas in order to reduce the particle size of the products. The addition of 20 vol.% H2 to reactant N2 gas decreased the combustion temperature from 2680 K to 2300 K. This led to an increase in specific surface area (SSA) of the product from 1.02 m2 · g-1 to 1.58 m2 · g-1. When 1.0 mass% of NH4F was added to the mixture of the raw Al powder and the AlN diluent, the residual Al was reduced from 1700 ppm to 200 ppm. The AlN powder synthesized with the addition of 10 vol.% of H2 gas and 1.0 mass % of NH4F was fully densified at 1810°C under 0.11 MPa of N2 pressure for 180 min. The thermal conductivity of the sintered AlN measured by laser flash method was 160 W · m-1K-1.
  • 渡利 広司, 杵鞭 義明, 石黒 裕之, 森光 英樹, 内村 勝次
    2005 年 52 巻 10 号 p. 763-766
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    Films with thickness ranging from several ten μm to several mm are of great interest due to their application or necessity in highly integrated, small electric devices. In this work, we report the processing merit of a novel centrifugal sintering, which densifies metallic film by applying high pressure, in the absence of a pressure medium such as graphite bar in hot-pressing equipment. Cu thick film on SiO2 substrate has been prepared for studying the sintering behaviour. It is observed that the pores and cracks in the specimens were drastically removed, and then promoted its densification by centrifugal firing, compared with conventional firing.
  • 砂本 健市, 中崎 信行
    2005 年 52 巻 10 号 p. 767-771
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    Many electric current sintering machines are currently used, since short-time heating and sintering of highly dense compacts can be realized by making use of Joule heat. However non-uniform temperature distribution inside the mold in the conventional electric current sintering machines was a disadvantage and hence was not necessarily suitable for the commercial production of high grade sintered materials for electronic devices. Multi-axis electric current sintering equipment, which has a vertical pressing axis and two independent horizontal current axes, has been developed to solve the above problem.
    The present study was carried out using this equipment. Temperatures inside the graphite mold of 140 mm inner diameter were measured for single axis electrification and two axis electrification by alternately changing the current axis. It was found that the temperature at the center was lower than that at the point of 62 mm from the center and that in the latter case the temperature difference was successfully controlled to 10 K, whereas in the former case the temperature difference was as large as 100 K.
特集 光機能材料
総報
研究
  • 水野 めぐみ, 垣内田 洋, 高橋 雅英, 徳田 陽明, 横尾 俊信
    2005 年 52 巻 10 号 p. 775-780
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    The structure of the organic-inorganic hybrid low-melting glasses prepared by the nonaqueous acid-base reaction was investigated mainly by 31P NMR techniques in order to elucidate the chemical durability-structure relationship. By increasing the reaction temperature, it is possible to improve the conversion, resulting in increase of the network dimensions of the resultant glasses. It is found that the glasses of high degree of condensation tend to have better water durability in a humid atmosphere. In addition, gold nanoparticle doped and gold-dye co-doped glasses were prepared by the acid-base reaction. The efficient energy transfer from gold nanoparticle to dye was observed by the photoluminescence measurement.
  • 平尾 崇行, 村井 俊介, 藤田 晃司, 中西 和樹, 平尾 一之
    2005 年 52 巻 10 号 p. 781-785
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    The tuning of light scattering strength has been demonstrated for organic-inorganic hybrid monoliths with well-defined through-pores in micrometer range. Macroporous gels having interconnected pores and skeletons are obtained in a system containing methyltrimethoxysilane, water, nitric acid, and methanol using an alkoxy-derived sol-gel method combined with the phase separation. The sizes of pores and skeletons can be controlled by varying molar ratios of water and methanol in the starting compositions which mostly affect the onset of polymerization-induced phase separation in the system. The mercury porosimetry shows that the resultant gels have a sharp pore size distribution, and the average pore diameter increases with increasing the amount of water and methanol. The coherent backscattering measured for the gels formed in between two slide glasses reveals that the transport mean free path of light decreases with decreasing the sizes of pores and skeletons. Pore size dependence of the scattering strength can be qualitatively explained by a Mie scattering calculation using a model in which spherical pores are randomly distributed in methylsiloxane matrix. The results indicate that the scattering strength can be tuned by controlling the sizes of the pores.
  • Katsuhisa Tanaka, Sakiko Ukon, Yoshinori Yonesaki, Rikuo Ota
    2005 年 52 巻 10 号 p. 786-789
    発行日: 2005年
    公開日: 2006/04/28
    ジャーナル オープンアクセス
    Second-harmonic generation (SHG) has been observed in optically poled TeO2-WO3 glasses doped with vanadium. The second-harmonic (SH) intensity depends on the concentration of vanadium; the glass doped with 0.1 mol% of V2O5 manifests the maximum SH intensity. The SH intensity is larger and the second-order nonlinearity is more stabile for 20WO3 · 80TeO2 glasses than for 15Nb2O5 · 85TeO2 glasses reported previously. Besides, enhancement of SH intensity is observed in glasses co-doped with rare-earth element such as Tb, Pr, and Ce in addition to vanadium. We speculate that Tb4+, Pr4+and Ce4+ play a role of trap centers for electrons; a positive hole trapped at V4+ as well as the electron trapped at the tetravalent rare-earth ion forms internal dc field, the spatial periodic variation of which gives rise to SHG.
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