巻号一覧
34 巻, 7 号
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古川 信雄1987 年 34 巻 7 号 p. 283-290
発行日: 1987/09/25
公開日: 2009/12/04
ジャーナル フリーThis report explains the history of the developments of the ferrous sintered structual parts by illustrating the progress of their production technology in Japan. The production technology includes the production equipment and the iron powders, in addition to compacting and sintering. Their progress resulted in the improvement of the quality and mechanical property of sintered parts and the expansion of their application in the market. The production of the ferrous sintered structural parts started with the introduction of the foreign technology, but, since 1965, the domestic technology has been fostered and the 1970s have seen a significant expansion of the sintered parts markets through the developments of the technology by our own. In the 1980s Japanese production technology of sintered parts has reached the leading position in the world. In the future, we will be able to expect more expanding and hopeful market for those sintered parts by achieving the revolution of their production technology.抄録全体を表示PDF形式でダウンロード (4936K) -
山本 孝, 岡崎 清, Ed. Goo, G. Thomas1987 年 34 巻 7 号 p. 291-295
発行日: 1987/09/25
公開日: 2009/12/04
ジャーナル フリーMicrostructures of Pb(Mg1/3Nb2/3)O3 ceramics were studied by using a x-ray analysis and transmission electron microscope (TEM) with energy dispersive x-ray analysis (EDX). In general, perovskite phase of Pb(Mg1/3Nb2/3)O3 is prepared by four different techniques: Conventional sintering (CS), Presintering (PS), CS with excess MgO (CSE), and PS with excess MgO (PSE). At the low sintering temperature of 850°C in the CS method, pyrochrore phase was located in the triple junctions and surrounded by the amorphous PbO. With increasing the sintering temperature to 900°C, pyrochrore phases were reduced and many MgO particles were observed near the pyrochrore phases. From these experimental results, the synthesis process of single phase of Pb(Mg1/3Nb2/3)O3 was classified into three parts; firstly, PbO among PbO, Nb205 and MgO powders melt and reacted with Nb2O5. The pyrochrore phases were composed at the low sintering temperature. Secondly, the pyrochrore phases gradually transformed into perovskite phases by the diffusion of MgO. The chemical composition of pyrochrore phase in the sample sintered at sintering conditions of 850°C for 2 hrs was Pb2.25(Mg0.27Nb1.79)O3. Thirdly, the single phase of Pb (Mg1/3Nb2/3)O3 perovskite was composed at the more higher sintering temperature by the mutual diffusion of excess Pb and Nb and Mg which are deficient in the pyrochrore phase.抄録全体を表示PDF形式でダウンロード (3120K) -
Merl 76粉末の液相焼結と組織変化森下 政夫, 永井 宏, 庄司 啓一郎1987 年 34 巻 7 号 p. 296-301
発行日: 1987/09/25
公開日: 2009/05/22
ジャーナル フリーThe microstructural changes during the sintering process of Merl 76 powder and the solidification process of melted Merl 76 powder were investigated through DTA, microstructural observation and EPMA.
DTA during the sintering and the solidification processes of Merl 76 powder detected five endothermic and five exothermic reactions, respectively. Although the phase reactions during both processes occurred in approximately the same temperature range, the microstructural observations and EPMA analyses of the phases revealed that the phase reactions during the sintering process were not reversed to those during the solidification process. The microstructures observed during the sintering process approached those found during the solidification process after holding in the respective temperature ranges.
Rapid densification of Merl 76 powder compacts occurred in the temperature range of 1st reaction, which corresponded to the incipient melting. The microstructure of Merl 76 powder was consisted of fine dendritic structure. In the temperature range of 1st reaction, the liquid phase appeared in the regions between the dendrite arms and the amount of the liquid phase increased, changing its composition with increasing holding time.抄録全体を表示PDF形式でダウンロード (5408K) -
井手 恒幸, 中野 和則, 高木 研一1987 年 34 巻 7 号 p. 302-308
発行日: 1987/09/25
公開日: 2009/12/04
ジャーナル フリーThe sintering phenomena of Fe-6 wt%B-(0-58) wt%Mo alloys are studied by means of TG-DTA, dilatometric measurements and X-ray diffractometry. In addition, the mechanical properties of the sintered alloys are discussed.
The optimum process-property relations can be summarized as follows:
(1)Highest transverse rupture strength values around 200 kg/mm2 are obtained for the 48 wt%Mo alloy.
(2)The 48 wt%Mo alloy consists of the Mo2FeB2 and a small amount of Fe2B as hard phases and of an Fe binder phase.
(3)The Mo2FeB2 phase is formed in the temperature range 750-1090°C. The liquid phase sintering of the alloy is accomplished by two different liquid phases produced by two different reactions. The first reaction, γ-Fe+Fe2B→L1, occurs in a temperature range 1090-1150°C, this being somewhat lower than expected for the binary Fe-Fe2B system presumably due to the presence of Mo. The second reaction, γ-Fe+Mo2FeB2→L2, occurs above 1150°C.
(4)The optimum sintering temperature lies slightly above the temperature at which the reaction γ-Fe+Mo2FeB2→L2 occurs.抄録全体を表示PDF形式でダウンロード (3738K) -
小堀 景一, 植木 光生, 近藤 博喜, 鈴木 寿1987 年 34 巻 7 号 p. 309-313
発行日: 1987/09/25
公開日: 2009/12/04
ジャーナル フリーThe microstructural defects acting as fracture source in P30 alloy, prepared by the use of recycled starting powder, were studied. Special defects, that is, pores accompanied by the βt layer (A1 defect) and binder pools to which βt layer attached (A2 defect) were often observed in sintered alloy and HIP-treated alloy, respectively. The strength of HIP-treated alloy was sharply affected by the appearance of the A2 defect. It was confirmed that the formation of A1 defect was caused by the segregation of extremely fine particles of impurity oxides, etc., where the segregation took place inevitably in the mixed powder. The result of model experiments showed that impurity atoms dissolved in the binder phase at the periphery of pores and then decreased the solid-solubility of W. It was suggested that the concentration gradient of W, Ti and Ta solutes in the liquid binder was produced near the pore, leading to the formation of the βt layer as above mentioned.抄録全体を表示PDF形式でダウンロード (6156K) -
八谷 繁樹1987 年 34 巻 7 号 p. 314-317
発行日: 1987/09/25
公開日: 2009/05/22
ジャーナル フリーThe sputtering was applied to the vapor source of the gas evaporation technique which is one of physical techniques to produce ultrafine particles. Two kinds of sputtering techniques were tried; one is sputtering with an aid of a thermal electron and the other is the ordinary one with two parallel electrode plates. W, and Ag and Cu are chosen as a test sample. Particles of W, and Ag and Cu are formed by the former and the latter, respectively. Reactive sputtering results in the formation of WC1-x particles.抄録全体を表示PDF形式でダウンロード (3163K) -
金子 裕治, 穴本 修司, 濱村 敦1987 年 34 巻 7 号 p. 318-324
発行日: 1987/09/25
公開日: 2009/05/22
ジャーナル フリーThe effect of Al2O3 and Cr2O3 additives was investigated on Curie temperature, lattice constants, magnetic properties and particle shapes of the calcinated Sr-ferrite, and on the permanent magnet properties of the sintered Sr-ferrite. With increasing the amount of Al2O3 additives, Curie temperature was decreased, the lattice constant was contradicted and the intrinsic coercivity was considerably increased. In case of Cr2O3 additives, Curie temperature was slightly decreased, but little change was observed on lattice constant. The intrinsic coercivity was slightly increased. In terms of the additive effects, the intrinsic coercivity of the sintered Sr-ferrite showed a similar tendency to that of the calcinated Sr-ferrite. It could be concluded that the Al2O3 additive controlled the intrinsic coecivity by forming solid solution with Sr-ferrite, and Cr2O3 additive behaves to control the grain growth of Sr-ferrite. By simultaneous adding of SiO2 and Al2O3 or Cr2O3 additives in pre-calcinating stage, we have cleared the hurdle of obtaining the high quarity magnets of Br=4.1 KG, iHc=4.0 KOe and or Br=3.8 KG, iHc=5.0 KOe, which were keenly claimed by car motor makers.抄録全体を表示PDF形式でダウンロード (3240K)
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