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Anodic protection of electroless nickel tanks
Q. We use anodic protection of 316 SS tank for electroless nickel plating (high phosphorus acid bath, hypophosphite based solution ) Some tanks performed better than others : lower anodic current, less plate out on cathode rods. Others had consistently higher anodic current, no matter how long the nitric acid passivation was. Some tanks look darker than others (possibly due to nitric acid corrosion while stripping the tanks with anodic current on ) and yet the performance of anodic protection is NOT related to the color at all. We are sure that there is no shorting of circuitry. Literatures were read & studied. However, we still do not understand the fundamentals of the problem. We are considering electropolishing the tanks to resolve the problem.
- (1) Why some tanks are better than others in protection ?
- (2) Please compare chemical polishing and electropolishing, which one is better ? ( to give higher Cr / Fe ratio )
- (3) How different electropolishing techniques and electrolytes can affect the tank with respect to anodic protection ? Why ?
- (4) Can we just plate chromium over the SS tank for permanent protection ?
? Paul, Have some of your answers and many of the same questions? Your note is one year old. Do you still need a response? Am in the disc drive industry. 316 SS anodically protected tanks. Using Kikusuis, Daisy chained to walls, spargers, intakes, heaters, etc. Need defect correlation to anodic (mA) readouts. You still there?
I have just read your message dated, and I have the very same questions. Did you receive any responses to your queries. If so would you care to share them with me.
- Limavady, N.Ireland, UK