| 摘要 |
PROBLEM TO BE SOLVED: To produce spheroidal copper powder suitable for a metallic paste material for a thick film process forming an electric circuit by mixing alkaline earth metal salt and copper salt to form into metallic copper by a dry reducing reaction with hydrogen, reducing it with hydrogen and thereafter dissolving the alkaline earth metal salt with acid. SOLUTION: At least one kind of alkaline earth metal salt (magnesium oxide, calcium oxide or the like) is mixed to copper salt (basic copper carbonate, cuprous oxide or the like) to form into metallic copper by a dry reducing reaction so as to regulate the weight of the alkaline earth metal salt to 0.05 to 3 times that of the metallic copper, and this mixture is reduced with hydrogen. The mixture is cleaned by using sulfuric acid and hydrochloric acid which do not dissolve the metallic copper, and the alkaline earth metal is dissolved away to obtain spheroidal copper powder. In this way, the spheroidal metallic copper powder with 0.1 to 10μm average grai size suitable for a metallic paste for a thick film process forming an electric circuit in screen process printing or the like can easily be produced.
|
