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


-----

Electrolytic cleaning - anodes

I have a question about cleaning of copper parts in strong alkaline solutions of sodium hydroxide/sodium carbonate / washing soda [affil links]. We have recently tried cathode electrolytic cleaning and found it to be very effective. The cleaner can operate at ambient temperature and achieve same result as a hot soak (45°C or 110°F) in about the same time, thus saving energy. However, one problem is plating out of dissolved metals creating a grey/silvery scum over the copper surface. The scum is mostly washed away in the acid cleaning that follows. I am wondering if the stainless 316 anode is dissolving in to the NaOH cleaner and plating out on the cathode. What anodes materials are commonly used in alkaline electrolytic cleaning tanks?

Is reverse cleaning (workpiece becomes the anode) necessary to remove the contaminant?

Adam Seychell
- Melbourne, Australia
2002

---

Plain steel should be used for those anodes. Reportedly, chromium can be leached out of stainless steel anodes in electrocleaners, although I'm not personally aware of any proof of that report; but steel is much less expensive anyway.

The Electroplating Engineering Handbook [on AbeBooks or eBay or Amazon] recommends anodic cleaning of copper and copper alloys, rather than cathodic. Cathodic cleaning can lead to smut problems.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2002

WE ARE USING SS PLATE AS ANODES IN REEL PLATING.

KASI VISWANATHAN
- Penang, Malaysia
2003