Topic: Porosity ( bubbles ) in sulfamate nickel plating

I am not a plater, but have been designing and consuming lots of plated parts over he years.

I have a 1008 Steel part with sulfamate Nickel plating and experiencing bubbles or opens pits in the plating whcih cause corrosion in the end application. Due the application I cannot copper flash under the Ni.

What are possible causes for the open pits? I would assume gas generated at the surface, but what is potential root cause?



Re: Porosity ( bubbles ) in sulfamate nickel plating

Typically pitting is caused by gas bubbles formed during the plating operation.  Usually, a wetting agent is added to the bath to facility the removal of the bubbles during the process.  This, when combined with some sort of solution movement (via air agitation, mechanical movement, etc), usually eliminates the pitting.  Your supplier could also try to use a lower current during the plating process to slow down the formation of the gas bubbles, in effect giving more time for the bubbles to dissipate.  But first I would have them check the wetting agent and solution movement.

A copper strike under the Ni wouldn't have much affect on the pitting (although it would help with the corrosion, as you mentioned)

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer


Sanford, NC

Dr. A.

Re: Porosity ( bubbles ) in sulfamate nickel plating

Some other possibilities;

1.  Organic contamination.

2.  High pH

3.  Low boric acid concentration.

4.  Anode to cathode ratio out of whack.

5.  Poor contact.

6.  HIgh iron concentration in the bath.

7.  Low wetting agent.

Hope this helps!