Chemical Quality and Electroless Nickel

Q: We recently changed our supplier of sodium sulfide and sodium hypophosphite used in our electroless nickel plating baths. Since making this change we have had nothing but problems with the process. Two of these problems are brown stains and plating out of nickel on the tank walls. Do you have any suggestions for resolving these problems? C. S.

 

A: Your e-mail indicates that you did not have these problems prior to switching suppliers for sodium sulfide and sodium hypophosphite. Hence, the first thing I would do is go back to your previous supplier and use his materials when preparing your next tank of plating solution. If the problems disappear, then you have solved the problem. If the problem still persists, then you will have to do some troubleshooting to determine what is causing the problems.

I would recommend that you get a copy of the book, Electroless Nickel Plating by Wolfgang Riedel, ASM International/Finishing Publications Ltd. The book is available from Amazon.com and probably is available from other sources also. This book is a necessity for anybody involved with EN deposition.

This question illustrates an issue that is not uncommon in the industrial world, namely, differences in quality and purity of materials. It is only human to want to try to obtain the lowest price for a material or product. This is fine but very often quality will decline in the rush to beat somebody else’s price. I could regale you with many stories about major problems caused by poor quality raw materials. I also do not recommend “home-brew” cleaners and plating baths for the same reasons: Consistent quality of the components and consistent formulation.