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Burrs from electroless nickel plating process

I have an application using spring energized vacuum seals. The surface quality of the seal gland is very important. Currently, we electroless nickel plate these surfaces because high hardness is required as well as corrosion resistance. The problem is that the parts we've been receiving have microscopic burrs on them that scratch the seals and cause vacuum leaks when installed. Is there anything that can be done to prevent this. Our plater said it depends on bath and filter cleanliness. The plater said he changes the filter and bath before each lot of our parts that he runs, but we still are getting the parts with burrs on them. Please help.

James Biesinger
semiconductor equipment manufacturing - Bethesda, Maryland, USA
2004

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If the burrs were on the substrate, I think you'd have heard complaints from the plater. It sounds like he's causing the burrs with his plating process and knows it. I don't quite understand why he changes the bath before each lot of your parts, since that is unusual -- so I wonder if he uses that tank for something else like a composite plating process which would have particles in it? That doesn't sound too likely either, but the situation isn't quite making sense to me yet.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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First of two simultaneous responses --

Are the parts de-magnetized? The micro roughness can also be caused by a bath loading/stability issue with the chemistry of the electroless nickel bath.

Todd Osmolski
- Charlotte, North Carolina, USA
2004
2004

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Second of two simultaneous responses --

It might be the plater and it might not. Changing the filter before a run is not the equivalent of having good filtration. Also, nothing was said about the pore size of the filter or the turnovers per hour or how dirty the filter is when it is removed. Since I have the toys, I would suggest filtering a quart of it on a membrane filter and check the filter under a good magnification. I have a suspect that the parts are slightly smeared in manufacturing and that the cleaning / etch process is raising the burr. It might be possible to break off some of the burrs under a 3-30 microscope and draw a conclusion about what is inside of the nickel plated burr--trash or metal.

James Watts
- Navarre, Florida
2004