Where the
world gathers for metal finishing
Q&As since 1989


-----

Brown scales on Zn- Co passivated components

We are manufacturers of sheet metal components, electroplating is one of the finishing operation we perform. The plating we do is Zinc-cobalt passivation, in boric acid bath. problem that we face is that sometime the component carry brown scales on them after passivation. We couldn't understand the cause of there occurrence. On finding components with theses brown marks we refresh the electrolyte bath and start plating again. kindly tell us the cause of there occurrence and remedy to prevent it.

Abhinav Banthia
sheet metal components - Jaipur, Rajasthan, India
2003

---

2003

Dear Mr Abhinav,

Never heard of this problem yet, but I do think you are overdosing your bath with additives. When you 'refresh' your bath you are restoring balance and the problem obviously disappears.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India