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Volume 34, Issue 3
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[in Japanese], [in Japanese], [in Japanese]1987 Volume 34 Issue 3 Pages 101-106
Published: April 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (4050K) -
Atsushi Nishino, Hironao Numoto, Yasuhiro Takeuchi, Yukiyoshi Ono1987 Volume 34 Issue 3 Pages 107-113
Published: April 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSA low temperature calcined catalyst carrier which is composed of calcium aluminate, fused silica and titanium dioxide has been developed. This catalyst carrier is washcoatless because of its high specific surface area, and it is now being used commercially as a home-use catalyst.
The production method of the carrier is following: Carrier components in powder form are well mixed and then an adequate amount of water is added to the mixed powder to make the mixture paste for molding honeycomb. The curing of the molding is done in hot water and then the carrier is calcined at a low temperature range from 700 to 900°C.
The purpose of the present paper is to study the relationship between the carrier components and physical properties such as the compressive strength, the thermal expansion coefficient and the specific surface area.
The main results obtained are as follows:
1) The low temperature calcined catalyst carrier is practically usable at the temperature range from 400 to 1000°C.
2) Sintering of the carrier begins gradually above 700°C.
3) The thermal expansion coefficient of the carrier depends on the average particle size of fused silica used as the aggregate.
4) The thermal shrinkage of the carrier effectively depends on the average particle size of fused silica and thermal treatment temperature rather than the calcium aluminate content.View full abstractDownload PDF (2683K) -
Ryuzo Watanabe, Yutaka Takeshima1987 Volume 34 Issue 3 Pages 114-117
Published: April 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSHigh temperature consolidation of chromium powder in a vacuum-scaled glass mould under atmospheric pressure (CAP of chromium powder) was studied. Densification and microstructural development during the CAP process were investigated by the density measurement and the structural observations on the CAP'd compacts. The CAP process was found to be effective for the densifying chromium powder compact at sufficiently low temperatures. The CAP'd compact was observed to have a characteristic three-layer structure; the glass-penetrating outer layer, intermediate porous layer and dense core. The pore surfaces were covered with thin glassy film, and polyhedral particles, the main component of which was confirmed to be chromium, distributed in the dense core region. These particles were observed to be formed at the pore surfaces and they seemed to grow until they filled the pore volume, eventually dissolve into the chromium matrix. The densification was supposed to proceed from the central region of the compacts towards the outer layers, with squeezing the glassy film wetted over the pore surfaces.View full abstractDownload PDF (3978K) -
Shiro Kohara, Kiyohiko Tatsuzawa1987 Volume 34 Issue 3 Pages 118-122
Published: April 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSSintering behavior of Fe-Ni-P compacts prepared by electroless plating on iron powder was studied by means of dilatometric method and electron probe micro analysis. The sintering of Fe-Ni-P plated powder compacts containing phosphorous in the plated layer more than the eutectic composition of Ni-P alloy was enhanced compared with the case of Fe-Ni plated powder compacts. The following mechanism was proposed for the enhanced sintering in the compacts of Fe-Ni-P plated powder: During heating up to about 1123K, stable Ni-P alloyed layer exists between iron particles, and enhanced interdiffusion of nickel and phosphorous, caused by lowering the liquidus temperature with increasing phosphorous content of Ni-P alloy, promotes the sintering of Fe-Ni-P compacts. Also, during heating from the temperature range above the Ac3 point of iron to the initial stage of isothermal sintering at 1423K, transient alpha phase is maintained by preferential diffusion of phosphorous into iron. Since the diffusion rate of nickel in ferrite-alpha phase is higher than that in austenite-gamma phase at the same temperature, increased volume diffusion of nickel in the alpha phase promotes the sintering of the compacts.View full abstractDownload PDF (1665K) -
Masaru Yokota, Hideki Moriguchi, Akira Takase, Keiichiro Shoji1987 Volume 34 Issue 3 Pages 123-128
Published: April 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSFor the purpose of estimating the damping capacity of composite structure type lead infiltrated iron compacts, the internal friction of them and of Fe sintered compacts for a comparison were measured, and influences of cold rolling and annealing on the internal friction were also studied. Results obtained were as follows:
(1) The internal friction of Fe sintered compacts increased with an increase of porosity of compacts up to about 26%. Beyond that, the internal friction was retained almost constant value regardless of an increase of porosity of compacts. The internal friction of Fe sintered compacts could be enhanced remarkably by the rolling. But the enhanced internal friction was thermally unstable, and was reduced to the level of assintered condition after a short-time annealing.
(2) The internal friction of Pb infiltrated Fe sintered compacts also increased with increasing both the Pb infiltration ratio and the rolling reduction. The internal friction of this material was thermally stable, i.e. the reduction ratio of internal friction was approximately one fifth after a prolonged annealing time. The damping mechanism of this material is thought to be mainly due to the absorption of vibration energy by the external friction at the interface between Fe skeleton and Pb infiltrant.View full abstractDownload PDF (437K) -
Keiichi Kobori, Mitsuo Ueki, Yasuro Taniguchi, Hisashi Suzuki1987 Volume 34 Issue 3 Pages 129-132
Published: April 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSFor the purpose of increase in toughness of coated cemented carbides, studies on the formation of binder enriched layer near the surface (BEL) were carried out.
It was found that the BEL having lamellar structure of binder phase was apt to form when the alloy was cooled in decarburizing atmosphere after sintering. The BEL formation became easy with higher carbon content of alloy, slower cooling rate and higher sintering temperature. The formation mechanism of BEL, which would closely relate to rapid liquid flow during cooling from sintering temperature, was in detail examined.View full abstractDownload PDF (1708K)
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