Chloride in Sulphamate Nickel Plating Solution

Can a high nickel chloride content in a sulphamate nickel solution cause cracking of the deposit .018"
How can the nickel chloride content be reduced?
What are the possible causes of cracks in a sulphamate nickel deposit?

High chloride causes high tensile stress. The amount of chloride you need is a function of the kind of anode you use. If s-rounds, then 0.5 av oz/gal is enough. High ammonium iron causes brittleness. High ammonium ion is caused by high temperature, age, high anode current density. You need a complete analysis for all ingredients plus stress plus ammonium ion. There is no way to lower chloride. There is no way to lower ammonium ion.

The only way you can lower the chloride content of the bath is to bleed out some of the solution and replace it with virgin solution. Are you sure that it is a cracking issue? Is the nickel peeling from the substrate? i.e. Is it a precleaning or striking issue? It appears that you are sure that it is from the plating tank, so how are the other parameters of your bath? How is the ductility of your nickel? How is the hardness of your nickel? These are all very important questions you should be asking yourself. And here is an excellent article about stress: www.finishing.com/library/stein/stresspaper.html Good luck! Jim Schwartzmyer - North Tonawanda, New York, USA To avoid tensile stress, use nickel bromide instead of nickel chloride Sara Michaeli Tel-Aviv-Yafo, Israel

Yes..but Nickel Bromide in excess produces compressive stress in the deposit. This is also not good.