MANUFACTURE OF SILVER PLATED IRON AND IRON ALLOY

摘要

PURPOSE:To manufacture silver plated iron or a silver plated iron alloy maintaining the characteristics of the base metal and having superior electrically connecting and soldering characteristics by forming a chromium film on the silver or silver or silver alloy plated surface of iron or an iron alloy and carrying out rolling. CONSTITUTION:After a stainless steel plate is degreased, activated by cathodic treatment in an HCl soln., washed, and plated with silver by striking in a silver plating bath while protecting the activated state. A cyanogen bath consisting of AgCN, KCN, KOH and K2CO3 is suitable for use as the plating bath. By cathodically treating the plate in a soln. contg. >=about 100ppm sexivalent chromium ions such as a chromium trioxide soln., a chromium film is formed to fill the pinholes o the silver plating. Rolling is then carried out at >=about 2.5% reduction ratio to remove a chromate film formed on the plated layer and to reinforce the chromium film in the pinholes.