Process for direct gold plating of stainless steel

摘要

Stainless steel can be directly plated with gold by a process wherein stainless steel is dipped in an activating solution; the activated stainless steel is subjected to cathodic electrolysis in a cathode electrolytic activation solution and then the treated stainless steel is directly plated with gold. A preferable activating solution contains (i) 3 - 20 wt.% of HCI, (ii) 2 - 30 wt.% of H₂SO₄, (iii) 0.1 - 5 wt.% of a nonionic or cationic surfactant and (iv) 0.1 - 20 wt.% of 2-pyrrolidone or N-alkyl-2-pyrrolidone. A preferable cathode electrolytic activation solution contains (i) 5 - 20 wt.% of H₃PO₄, (ii) 2 - 10% HNO₃, (iii) 0.1 - 5 wt.% of a nonionic or cationic surfactant and (iv) 0.1 - 20 wt.% of 2-pyrrolidone or N-alkyl-2-pyrrolidone.