| 摘要 |
PURPOSE:To clean and activate thoroughly the rugged surface part of a steel stock and to eliminate defective electroless plating by immersing the steel stock into a mixed bath prepd. by adding a metal cleaning and activating agent to a mixed acid base contg. a hydrochloric acid as a main agent and a sulfuric acid as assistant. CONSTITUTION:The mixed acid bath is prepd. by adding 1-5 g/l metal cleaning and activating agent contg. sodium gluconate as the main agent and contg. sulfanic acid, triethanol amine, acidic ammonium fluoride, etc., if necessary, to the mixed acid base mixed with 60-80 ml/l 35% hydrochloric acid 15-25 ml/l 98% sulfuric acid. The electroplating stock of the free-cutting steel is dipped into such bath for about 10 seconds. The rugged part an cavity, etc., on the surface of the steel stock are cleaned and activated by such treatment. The defective electroless plating is decreased according to the above-mentioned pretreatment. The reduction in the product cost and the improvement in the safety of the operation are made possible. |
