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Electroless Nickel Plating, too dull on one run

Good afternoon.
We have 2 parts(CRS) of an assembly that get electroless nickel plated. We have spec'd out a 32 micro or better finish before plating but on this latest run the parts came out looking rather dull and dark.
Can you tell me what might have caused this?
Thanks in advance for any help you can provide.
Sincerely,

Steve Cornette
Product Engineer - Nicholasville, Kentucky, USA
March 5, 2009

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First of two simultaneous responses --

It could be one or more of several things. Your bath could have been contaminated. You could have had poor preplate processing. The bath chemistry may have been out of balance, etc. If you are using (I hope) proprietary chemistry, contact you supplier and ask for help and a troubleshooting guide (most suppliers have them)

Gene Packman
process supplier - Great Neck, New York
March 10, 2009

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Second of two simultaneous responses --

It sounds like the brightener component of the EN ran out. Another possibility is that the tank had built up enough aluminum to cause the darkening. It would be nice to know which set of parts was run before the other one.

James Watts
- Navarre, Florida
March 10, 2009

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First of two simultaneous responses -- March 17, 2009

How many metal turn over have you run?
For aluminum 4 MTO is enough

Sara Michaeli
Tel-Aviv-Yafo, Israel

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Second of two simultaneous responses --

The electroless nickel line in which Steve is talking of is a plating on plastics line. It is either over etching, or your E-Ni is off. What is the reading of deposit?

Rob Coffie
Warren, Michigan, USA
March 17, 2009

Dark deposition in electroless nickel is mainly due to the excess etching time. Control the etching time if you plate on plastic. then the second possibility is low concentration of nickel in your EN tank; check your nickel content, lastly look at the pH and raise it.

Eren S. AKAR
- Izmir, Turkey
March 18, 2009

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Rob,
If he is plating on plastics, why did he say that the part was(CRS) which I assume is cold rolled steel.

James Watts
- Navarre, Florida
March 19, 2009

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March 20, 2009

James I did not see the CRS, I assumed P.O.P.
Due to the City (Nicholasville) where a large
P.O.P. plant is. My assumptions were incorrect. :(
Sorry for the mistake.

Rob Coffie
Warren, Michigan, USA