Layers Of Nickel

Q: Our company barrel plates small components using a nickel sulfamate plating bath. The bath also contains a small amounts of nickel bromide. The barrels are 25–30% full and the bath is operated at a temperature of 120° and a pH of 4.5–5.0. Each barrel contains two danglers. The rotation of the barrel is approximately five rpm. The problem we have is the nickel appears to be layered and tends to delaminate during subsequent processing. Do you have any suggestions for solving this problem? J. W

 

A: Even under the best of operating conditions, barrel plating can be somewhat intermittent. There are a number of things that you should investigate in trying to solve this problem.

1. Barrel loading can play a part. It may very well be that a load factor of 20–25% gives better results than the 25–30% that you are now using. It could also be that a larger load factor, say 35%, will give you better results. Some experimentation should allow you to pin this down.
2. pH can play a role in this problem also. I would suggest that you try to hold the pH of your plating solution at 4.2–4.5.
3. Raising the bromide concentration should also help but you must be careful to not increase the concentration to a point where brittleness becomes a problem.

It would seem to me that with some experimentation you should be able to pin down a better set of operating condition