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Can't achieve electroless nickel finish that is dull enough

June 25, 2008

Dear Plating Experts,
I just about tried all the semi-bright and matte finish electroless nickel out there, but I need a more dull electroless nickel finishing on my substrate. The substrate is 300 series S.S., so I can't etch it. I was wondering if I can add something to the bath to make the deposit more dull. No tech service from any big companies can help me. I was wondering if adding little zinc (ppm level) or to the bath will help?

Any help will be great.
Thank You

June Kim
plating shop - Incheon, So. Korea

Why don't you try a very fine sand blast? Aluminum oxide mesh 320 or 400 are very fine and will not abrade too much specially if used at pressures of 40-60 psi.

Guillermo Marrufo
Monterrey, NL, Mexico
June 27, 2008

Parts are too small and too many to sand blast.

June Kim
- Incheon, South Korea
July 1, 2008

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July 1, 2008

1. 300 SS can be acid etched but it can go bad rapidly.
2. ferric chloride [on eBay or Amazon] and HCl will attack it fairly uniformly. The addition of about 1 gram of copper chloride will speed it up.
3. Aluminum oxide blast is not sand blast. Big difference.
4. There are rotating basket attachments for some blast cabinets that will allow blasting of small parts. Yes, it requires attention to the pressure, but it works well on bulk parts.
5. Work with your EN vendor to reduce the amount of brightener in the EN tank. You buy the solution with the brightener as a separate component and add it as desired, very very carefully.
6. The addition of aluminum will darken the EN . Test this out in the lab with a solution of EN tank that you are about to
dump.

James Watts
- Navarre, Florida