| Co-Investigator(Kenkyū-buntansha) |
SASAKI H. Faculty of Engineering,Hokkaido University, 工学部, 助手 (20196174)
SIBAYAMA R. Faculty of Engineering,Hokkaido University, 工学部, 助手 (80002012)
KIUCHI H. Faculty of Engineering,Hokkaido University, 工学部, 助教授 (90001247)
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| Budget Amount *help |
¥7,800,000 (Direct Cost: ¥7,800,000)
Fiscal Year 1988: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1987: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Research Abstract |
Reduction of aqueous salt solutions of gold, silver, copper and platinum group metals were studied. In cases with hydrogen reduction, gold and copper powders were composed of single crystals a few microns in diameter. Silver and palladium powders obtained were irregular in shape, whereas platinum powder had spherical particles 0.5-3 m in diameter. Reducibilities also varied among these metal species. In case of copper, hydrogen reduction required high temperature and hydrogen pressure, while platinum could be reduced under such milder conditions as 40゜C and atmospheric presser of hydrogen.
An addition of chloride ion of few mol/l showed drastic effect on yield of gold powder with disproportionation reaction. Shape and size of gold powder could be controlled with reaction temperature.
For the production of fine copper powder with disproportionation reaction (2Cu^+ Cu゜+cu<@12+<@D1) was studied. In order to obtain sub-micron copper powder, cuprous sulfate solution made by means of hydrogen reduction or disproportionation reaction at high temperature, e.g., 200゜C, should be rapidly quenched to temperatures lower than 100゜C.
Hydroquinone reduction of silver nitrate solution with palladium colloids in suspension brought Ag-20%Pd powder, however, feasibility tests of the powder indicate that the powder seems unadequate for thick film. The reason is not yet clear, however, large and deep crucks developed during sintering may have an important role.
Ag-10%Ni composite material for electric contact points was made from fine spherical silver powder which had been electroless-plated with nickel. The nobel material has higher dispersion of nickel than in conventional, and are now under feasibility tests.
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