Metal finishing Q&As since 1989
-----
Bright Nickel Speckling
Hello, I am having problems with nickel speckling or roughness. It is a bright nickel bath. The basis metal is steel, it's buffed then a nickel strike followed by the bright nickel. I've skipped the strike before and we still get the speckling. We've dumped and remade every acid, cleaner, and rinse. The bath is continuously filtered and we carbon treated recently. The hull cell looks perfect. Does anybody have any ideas?
Jason SmithLab Tech - Lansing, Michigan
May 2, 2011
I admit that I have limited knowledge of bright nickel, but in our limited experience with it I can mention three things to try;
1. Use a scrubbie on the parts before they hit the BN. Our parts were big and flat so it was easy to do that. But we always seemed to have a certain amount of residual debris left on the parts after pretreatment.
2. Use a smaller micron filter pad in the filter to remove finer debris.
3. Increase the flow in the tank around the parts by the use of spargers.
Hope this helps.
- North Tonawanda, New York
First of two simultaneous responses -- May 3, 2011
Second of two simultaneous responses -- May 4, 2011
Hi Jason
You really haven't given us enough information to go on, a photo may have helped.
Is the speckling on a top settling surface? or all over and on vertical surfaces?
The Hull cell isn't the best plating test for roughness type problems, having no horizontal surface. A J or bent cathode will more likely reproduce the problem in a beaker test.
Try filtering a litre through a buchner funnel and examining the filter paper closely for particulates or examine a litre of solution with a light behind for particulates.
Assume when doing a carbon treatment you checked anode bags to see if say S nickel fines were not causing the problem.
To eliminate the base metal as the problem try plating say a bent brass hull cell panel and see if this produces a similar problem.
While I could go on, think it best if you give more feedback after considering my comments
Geoffrey Whitelaw
- Port Melbourne, Australia
Check to see if you have a torn anode bag. The suggestion above for filtering through the buchner funnel is a good one. Use white filter paper to check for carbon and other dark material, and use black filter paper to check for anode bag particles and lighter material. Check to see if you have an air leak in the suction side of your filtration system. Tiny air bubbles introduced into the bath can give you speckling. Good Luck.
Chris Judt- Lititz, Pennsylvania, USA
May 5, 2011
May 8, 2011
Leaded steel will cause the defects. If the steel contains lead, a pyrophosphate or cyanide copper strike prior to the nickel would eliminate the problem. If the steel is not leaded, or has other similar constituents, filter both the nickel strike, if used and the bright nickel using 5 micron filter.
Filtering is best done by transferring the nickel solution to at clean storage tank then filter it back to the cleaned plating tank, using a 5 micron filter.
Don Baudrand
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [on Amazon or AbeBooks affil links]
and "Plating ABS Plastics" [on Amazon or eBay or AbeBooks affil links])
Have you checked that your cleaning is good? Is all the buffing compound being removed? If not, it may give you problems such as the one you have described.
John Reid- Brisbane, Qld, Australia
May 22, 2011
May 28, 2011
We had a similar problem a few years ago in our bright nickel. Tried everything as you have described. Cleaners, acids, anode bags, filters all changed and changed again with no luck. Hull cells looked good as well. We even tried a new wetting agent to no avail.
Finally we decided to empty the bath to make new when the problem was found. We had a lined steel tank and the liner had a small tear in it that was leaching steel into the bath. Not sure if you have a similar situation or not but thought I would throw that out there to you.
Best of luck!
- New Castle, Indiana, USA
Q, A, or Comment on THIS thread -or- Start a NEW Thread