著者

小堀 景一 植木 光生 府川 敦 鈴木 寿

出版者

一般社団法人粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.34, no.5, pp.217-221, 1987-07-25 (Released:2009-05-22)

参考文献数

3

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Mechanical properties, cutting performance, etc., of WC-β(WC/TiC=70/30)-TaC-TiN-Co alloy (cobalt contents, 8-8.5%) sintered in vacuum and nitrogen (PN2=2.7 kPa) were studied as a function of TiN/(TaC+TiN) ratios (named TiN ratios).The grain size of βt(WC-TiC-TaC-TiN solid solution) decreased with increasing TiN ratios and it naturally more decreased in sintering in N2, without change in the grain size of WC. The transverserupture strength, in particular, of HIP-treated alloy sharply increased with TiN ratios of more than 0.2. It was found that the resistance to oxidation of alloys was markedly improved with increasing TiN ratios.The results of cutting tests showed that the fracturing and flank wear resistances were scarcely affected by TiN ratios, but the cutting performance of the alloy sintered in vacuum was always superior to that of the alloy sintered in N2.

著者

青峰 隆文 西嵜 照和 山本 高広

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.37, no.1, pp.114-117, 1990

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It is known that sintered bulk samples of high Tc superconducting oxides have low critical current density and show hysteresis of critical currents in low magnetic fields. These phenomena are attributed to weak links at a grain boundary. In this work we report on the hysteresis of sintered bulk samples of high Tc superconducting oxides and of superconducting, relatively long bridges which have a constricted part made artificially. The former hysteresis is found to be very similar to the latter one. We consider that the hysteresis of sintered bulk samples of high Tc superconducting oxides occurs for the existence of superconducting, relatively long bridges and trapped flux in them.

著者

水上 正彦 山本 良治 浅田 信昭 松本 明英

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.53, no.2, pp.154-159, 2006-02-15

被引用文献数

2 7

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Nano-sized WC powder that is expected as the raw material for nano-sized WC-Co hardmetals with high hardness and strength was developed. The reaction path and morphological change in the reaction process of WO<SUB>3</SUB> with carbon powder (direct carburization) were firstly investigated by thermogravimetric analysis. The proper reaction condition examined by the thermogravimetric analysis was developed to trial production by direct carburization facilities.<BR>The direct carburization reaction from WO<SUB>3</SUB> to WC occurred through the generation of several intermediate products in the order of WO<SUB>3</SUB> → WO<SUB>2.72</SUB> → WO<SUB>2</SUB> → W → W<SUB>2</SUB>C → WC. The nano-sized particles were generated at the stage from WO<SUB>2.72</SUB> to WO<SUB>2</SUB>. We succeeded in the development of nano-sized WC powder less than 100 nm by controlling the reaction conditions for each intermediate products.

著者

大塚 愛子 川崎 亮 渡辺 龍三 厳 泰永

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.45, no.3, pp.220-224, 1998-03-15

参考文献数

7

被引用文献数

3 12

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Disk-shaped functionally graded materials of copper/alumina system have been fabricated by spark plasma sintering(SPS process. The graded layer consists of symmetrical compositional transition of Cu/Al<SUB>2</SUB>O<SUB>3</SUB>/Cu, which allows to achieve high heat conduction, electrical insulation and excellent in-plane electrical conductivity. The use of the FGMs as a compliant pad of conduction type of thermoelectric power conversion system offers high thermal energy density through the thermoelectric cell, resulting in the increase of the efficiency of thermoelectric energy conversion.<BR>This paper describes the process optimization including densification of metal-ceramic powder mixtures by SPS process, compositionally graded stacking of the mixed powders in a graphite die, the design of the compositional gradient on the basis of one dimensional heat conduction analysis and fabrication of Cu/Al<SUB>2</SUB>O<SUB>3</SUB>/Cu FGMs according to the predesigned compositional gradient.

著者

Goetzel C.G. Rittenhouse J.B.

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.14, no.5, pp.195-202, 1967

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粉末冶金の製品は,一般の航空方面への応用とともに,宇宙衛星の部品として利用されるようになった.宇宙衛星の関係部品は,高度に特殊化された目的を満足させるたあに,広範な発展計画を必要とするものである.この報告では,宇宙衛星に対するいくつかの粉末冶金の応用の紹介と,実際に軌道にのった宇宙衛星に使用された粉末冶金部品および材料の二,三の例について論ずる,粉末冶金製品の例として,93日間の飛行に成功したExplorer皿、のテープレコーダー中の焼結ブAンズベアリングがあり,また航空用衛星(その中には7カ月も活動したものもある)内の,自転抑制装置に用いられた焼結マグネットなどがある.化学的浸食熱応九融点近くの表面温度などに対する抵抗が要求されるようないわゆる高温熱流に対しては,Agを溶浸させたWが用いられる.これは粉末冶金法によってのみ作られるものである.この物質を十分に管理された製造工程のもとで製作するために,複合材料に最適の実用性質を発揮させるような広範な計画が開始された.粉末冶金法で製造されたBeの利点については,特に目下計画中,あるいは設計中の人間宇宙ステーションの表面材料として,および流星群の遮蔽防御などへの応用に対して検討されている.