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31 巻, 8 号
選択された号の論文の8件中1～8を表示しています
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宗宮 重行1984 年 31 巻 8 号 p. 253-259
発行日: 1984/11/25
公開日: 2009/05/22
ジャーナル フリーUltra-fine oxide powders can be prepared by hydrothermal oxydation, crystallization etc.
Dense bodies with ultra-fine grains are made by hydrothermal reaction sintering.抄録全体を表示PDF形式でダウンロード (5038K) -
宇津木 弘, 遠藤 敦, 鈴木 昇, 小野 和也1984 年 31 巻 8 号 p. 260-265
発行日: 1984/11/25
公開日: 2009/05/22
ジャーナル フリーThe surface-treatment of silicon nitride with pentanol, octanol and cetanol was investigated through X-ray diffractometry, scanning electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, pyrolysis and the flow property of the silicon nitride mixed with paraffine. The followings were found: (1) The surface of silicon nitride was covered by oxide film. (2) The crystallographic structure of the substrate, the shape or aggromeration of the grain and the surface area were not affected by the surface-treatment. (3) The surface groups were not detectable through infrared spectroscopy except the surface group including the long carbon chain. (4) The olefine similar to the alcohol used for surface-treatment was observed in the pyrolysis products of the surface-treated silicon nitrides in the temperature range of 350-500°C. This trend is the same as the pyrolysis of the surface-treated silica gels with alcohols. Thus the surface-treatment of silicon nitride was recognized to be performed by the reaction of the surface hydroxide of the oxide layers over the silicon nitride with the alcohol. (5) The amount of paraffine added to surfacetreated silicon nitride was found to be 10 wt% smaller than that to the non-treated one in order to show a certain flow property of the silicon nitride mixed with paraffine.抄録全体を表示PDF形式でダウンロード (1253K) -
1984 年 31 巻 8 号 p. 265
発行日: 1984年
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (16K) -
藤井 政俊, 神戸 士郎, 川合 知二, 河合 七郎1984 年 31 巻 8 号 p. 266-271
発行日: 1984/11/25
公開日: 2009/05/22
ジャーナル フリーThe electronic property and the photocatalytic activity of a semiconductor particle were determined by the electrochemical measurement and the hydrogen production experiment, respectively. The energy level of electrons at the bottom of the conduction band of the particle under irradiation was revealed to be different from that of a bulky electrode. This value involves the information on the relative position of the valence band of the semiconductor to the donor level of a reducing agent. The activity of hydrogen production from water-ethanol mixture with various platinized photocatalysts could not be explained by the property of the corresponding bulky electrode, but could be correlated with the obtained energy levels of the electrons under iradiation.
New photocatalysts, CdS1-x Sex solid solution particles, were prepared to obtain the desired energy level of the valence band, and their photocatalytic activities were examined by the hydrogen production experiment. The electronic properties of the solid solution particles were determined by the measurements of the luminescence and the photoconductivity. These experiments demonstrated that there are two determining factors for the activity of photocatalytic hydrogen production.
When the top of the valence band of the particle locates around the donor level of the reducing agent, the main determining factor is the relative position between the donor level of a reducing agent and the energy level of the valence band of a semiconductor particle. On the other hand, when the donor level is much more negative than the top of the valence band, the transport property of the carries in the particle mainly controls the reaction. With the choice of the proper composition of sulfur to selenium, the CdS1-x Sex photocatalyst can have the selectivity for the oxidation of organic compounds.抄録全体を表示PDF形式でダウンロード (452K) -
林 宏爾, 小野村 義弘1984 年 31 巻 8 号 p. 272-278
発行日: 1984/11/25
公開日: 2009/05/22
ジャーナル フリーSi3N4-(5-25) mol%MgO-(2-17) mol%Al2O3 ceramics were sintered in N2 atmosphere of 100kPa at 1973K for 3.6ks. The optical microstructures, mechanical properties, etc., of sintered compacts were investigated as a function of distance from the compact surface and contents of MgO and Al2O3.
It was found that the microstructural heterogeneous layer(HL) was generally formed near the surface of sintered compact. The formation of the HL was attributed to escapes of nitrogen and silicon from the compact surface during sintering. The amount of MgAl2O4 spinel, Si3N4 grain size, etc., in the HL differed in general from those in the inside of compacts. The HL reduced sharply the room-temperature transverserupture strength of the ceramics, owing to facts that the size of defects (pore) which acted as a fracture source was increased and the intrinsic strength was reduced in the HL, compared with those in the inside of compacts.抄録全体を表示PDF形式でダウンロード (4726K) -
焼結鋼におけるモリブデンの拡散合金化過程(I)沖 幸男, 秋山 敏彦, 庄司 啓一郎1984 年 31 巻 8 号 p. 279-283
発行日: 1984/11/25
公開日: 2009/05/22
ジャーナル フリーIn order to reveal the diffusion processes of molybdenum in sintered steels, diffusion couples prepared from powder mixture compacts were heated in vacuum at 1523K for 3.6ks, and the diffusion zones were examined mainly by means of EPMA.
Carbon in the iron-molybdenum diffusion couples intensively affected the diffusion layer formation through the carbide layers formation. In the diffusion couples containing carbon, the molybdenum diffusion in iron was considerably enhanced by using Mo2, C powder compacts as the coupling partner for iron powder compact or iron-carbon powder mixture compact, as compared with the use of molybdenum and graphite powder mixture compacts of the same composition. The difference in the degree of molybdenum diffusion was attributed to the iron-molybdenum-carbon ternary liquid phase formation in the interface of diffusion couple, as well as the diffusion in the solid phase.抄録全体を表示PDF形式でダウンロード (5130K) -
焼結鋼におけるモリブデンの拡散合金化過程(II)沖 幸男, 秋山 敏彦, 庄司 啓一郎1984 年 31 巻 8 号 p. 284-289
発行日: 1984/11/25
公開日: 2009/05/22
ジャーナル フリーAlloying processes of molybdenum in sintered steels were studied on the basis of iron-molybdenumcarbon phase diagram. Mixed powder compacts of iron-molybdenum-carbon system containing molybdenum carbide (Mo2C), metallic molybdenum, or ferro-molybdenum powder as a molybdenum additive were sintered in vacuum between 1273K and 1523K for 3.6ks, and the phases formed in these specimens were identified by means of X-ray diffractometory.
The results suggest that molybdenum diffuses into iron through a liquid phase produced by (γ-Fe)-Fe3C-Fe2MOC eutectic reaction and/or the M6C carbide formation. In the compacts containing molybdenum carbide powder, the diffusion of molybdenum tended to occur through the liquid phase, whereas in the compacts containing metallic molybdenum and Ferro-molybdenum powders it arose due to the formation of the M6C carbide. The degree of the molybdenum diffusion in iron-molybdenum-carbon compacts changed dependeng on the diffusion path.抄録全体を表示PDF形式でダウンロード (366K) -
塚本 雄二, 高橋 達尚, 駒井 宏行, 葉山 房夫1984 年 31 巻 8 号 p. 290-297
発行日: 1984/11/25
公開日: 2009/05/22
ジャーナル フリーThe friction and wear characteristics of copper-based sintered materials containing various intermetallic compounds were investigated under dry sliding conditions over a speed range of 1-4m/s, and compared with those of the Cu-A12O3 sintered compact. Four different kinds of intermetallics; CuAI, Cu2AI, Co2Ti and Ni3Al, were used to take account of both hardness and softening temperature. The fraction of added hard powder with a particle size of 105-150 μm was 16 vol% to copper powder,
The addition of the intermetallic powder with relatively high softening temperature such as Co2Ti and Ni3Al was quite effective, irrespective of the hardness, indicating that the softening temperature was the crucial factor for the improvement of the friction and wear behaviours. The Cu-Ni3A1 sintered material exhibited the most excellent tribological performance. The superiority of Ni3Al as an anti-wear additive may be caused by the formation of the softer diffusion layer which envelops the harder core of Ni3A1 particles, besides the high softening temperature and the positive temperature dependence of hardness. Al2O3 powder was further crushed to several fragments during sliding, because it is devoid of ductility. This results in an inferior wear resistance for the Cu-Al2O3 sintered material.抄録全体を表示PDF形式でダウンロード (6786K)
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