Periodic reverse current electroplating and surface finishing

Abstract

Using an alkaline cyanide bath at 20–90° C and periodic reverse (PR) current results in brilliant, level, and bright electroplated copper on any conventional metal substrate. The quality of the electroplate was evaluated by measuring the surface roughness and brightness. The surface roughness increases with frequency and amplitude of the PR current used for the plating. Increasing the bath temperature leads to brighter surfaces up to 50° C; higher temperatures have only a slight effect on brightness. The increase of catho dic-to-anodic period per plating cycle leads to a maximum brightness at PR ratio, cathodic/anodic, of 2 at 0·27 Hz. As the electrode separation decreases the brightness increases.