| 摘要 |
PURPOSE:To manufacture inexpensively copper powder coated with silver excellent in electrical conductivity and oxidation resistance by using silver complex salt consisting essentially of silver salt, ammonium carbonate salt and aq. ammonia, substituting and depositing metallic silver on the surface of metallic copper powder. CONSTITUTION:Metallic silver is substituted and deposited on the surface of copper powder by using silver complex salt soln. consisting essentially of silver salt of one or more kinds selected among silver nitrate, silver carbonate, silver sulfate and silver oxide, ammonium carbonate salt consisting of ammonium carbonate or ammonium hydrogencarbonate and aq. ammonia. Thereby, the copper powder coated with silver which is inexpensive and excellent in electrical conductivity, heat resistance and mixing resistance and extremely high in oxidative stability is obtained. In the above-mentioned method, the molar ratio of ammonia contained in ammonium carbonate salts and aq. ammonia is preferably about 0.2-6 and it is desirable that ammonium carbonate salts and aq. ammonia are excessively used for silver salt. |
