Journal of the Japan Society of Powder and Powder Metallurgy

Sintering Process of Slip Cast Specimens Made from Various Metal Powders

Takashi Kimura, Tadamasa Ogawa

1964 Volume 11 Issue 6 Pages 281-290
Published: December 25, 1964
Released on J-STAGE: December 04, 2009

DOIhttps://doi.org/10.2497/jjspm.11.281

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The sintering process of slip cast specimens made from various copper and silver powders was clarified by means of electrical resistivity and dilatometry measurements. It was revealed by the electrical resistivity changes of slip cast specimens as a function of temperature that the decrease in electrical resistivity at the early stages of sintering corresponds to the desorption of water vapor and adsorbed gases, decomposition of deflocculant and bonding of powders. The effect of the addition of deflocculant on the electrical resistivity changes was dependent upon the kind and shape of powders ; the smaller the particle size, the smaller the electrical resistivity values of both as-slip-cast and sintered. The specimens made from powders of complex shapes showed lower electrical resistivity than those from spherical particles. By means of dimensional changes as a function of temperature, the elimination of pores was mainly clarified, along with the other early stages of sintering. The dilatometric behavior of spherical copper powder specimens showed anormal expansion before shrinkage. The smaller the particle size, the faster the shrinkage. In sintering in hydrogen atmosphere the decrease of electrical resistivity and the shrinkage of copper powder specimens occured at lower temperature than in vacuo. The activation energy of densification of superfine silver powder specimens was determined to be 20, 000 cal/mol, which agreed with the activation energy of grain boundary diffusion.

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Sintered Manganese Stell. (Part II) Effects of Carbon Addition and Heat Treatment

Yasuaki Morioka, Teruhisa Watanabe, Shoji Wakabayashi

1964 Volume 11 Issue 6 Pages 291-299
Published: December 25, 1964
Released on J-STAGE: December 04, 2009

DOIhttps://doi.org/10.2497/jjspm.11.291

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Effects of the carbon addition and heat treatment on physical and mechanical properties were studied. The results obtained were as follows :
(1) The addition of carbon to iron-manganese alloys lowers the density and increases the porosity, but has a goot effect of improving the sintering between iron and manganese.
(2) Sintered manganese steel with the austenitic structure has good mechanical properties, particularly high impact energy, though the porosity of sintered compacts is higher than 150.
(3) In order to obtain homogeneous austenitic microstructure it is necessary to add high manganese and high carbon, for example C 2.0% for Mn 100 or C 1.2% for Mn 20% with sintering at 1200°C. (4) Mechanical properties are little affected by solution-treatment, but injured by heating at above about 400°C after solution-treatment. The hardness has the maximum value at a temperature of 500-600°C, since the platelet carbide precipitates at these temperatures.

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[title in Japanese]

[in Japanese]

1964 Volume 11 Issue 6 Pages 300-306
Published: December 25, 1964
Released on J-STAGE: May 22, 2009

DOIhttps://doi.org/10.2497/jjspm.11.300

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[title in Japanese]

[in Japanese], [in Japanese]

1964 Volume 11 Issue 6 Pages 307-315
Published: December 25, 1964
Released on J-STAGE: May 22, 2009

DOIhttps://doi.org/10.2497/jjspm.11.307

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