Electroless gold plating from tetrachloroaurate solutions containing hexacyanoferrate(II) ions

Abstract

A hexacyanoferrate–tetrachloroaurate electroless gold plating solution has been developed for production on Ni–P, Ni–B, Ni–Pd and Cu substrates, giving gold coatings up to 0·25–0·38 μm in thickness. The rate of gold deposition depends on the nature of the substrates and decreases in the series Ni–P>Ni–B>Ni–Pd>Cu. The rate of gold plating on Ni–Pd decreases with the growth of palladium content in the alloy. Gold deposition occurs by mechanisms of cementation (immersion replacement) and gold reduction with hydrazine hydrochloride. The fraction of cementation does not exceed 30–40% with deposition on Ni–P and Ni–B substrates, 10% on copper and diminishes slightly with gold film deposition.

Keywords:

• ELECTROLESS PLATING
• GOLD
• NICKEL
• PALLADIUM-NICKEL ALLOY