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Q&As since 1989
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Need process idea for coloring nickel plated brass
Q. I am plating a three part coupler that is made with C360 brass. We have been using a bright nickel plating on all three parts with success however, we have been trying to give some products a visual difference. Presently, one part has been required to be black in color. We require a process that will not allow for any corrosion or chemical reaction that may leave deposits on the black plated surfaces or the other bright nickel surfaces of our product. This product comes in contact with Auto Fuel and water in its use. Please give me options with potential corrosion issues. The other metals near the three brass parts include 420SS and 416SS (springs and balls). I want opinions on the stability of black-nickel which is an option but it is not as dark as I would prefer. Zinc? Black Oxide? a Sealer? I look forward to your recommendations, we have tried several things without the results we require. We have tried some options that created large quantities of white corrosion.
Thank you,
Craig LodarFluid Power Component Manufacturer - Cayuga, Ontario, Canada
2004
A. A true black is not easy to get with black nickel, but you should be able to get it in a light matte black-darker than a dark grey. It is a "soft" finish and thin. It would need to go over a base coat of nickel in most cases. Because it is soft, it is prone to scratching which will show as a bright line or spot on it. Black chrome is darker and more durable in most cases. I would look at zinc-nickel or zinc-cobalt alloy which can be a very dark but mottled black finish. Dyed zinc might be compatible with the fuel, but would need to be checked. Lots of colors there. Several colors of chromate conversion coatings for zinc are also possible.
James Watts- Navarre, Florida
2004
A. Zinc Iron with Black will definitely work. Increasing the iron in the deposit to 1.5 % will give you good hardness and may substitute for black nickel as well.
Khozem Vahaanwala
Saify Ind
Bengaluru, Karnataka, India
2004
A. Mr Craig Lodar
While I am in agreement with Mr Vahanwala on the Zinc Iron black passivation approach, one could also consider the following finishes in Black..over Nickel...
- Black Chrome over Nickel. It is fairly hard, though not more than 650-700 Vickers at the very most..
- Anthracite , which is a Black alloyed tin system , that is softer than Nickel but can withstand fuel well.
These alternatives have merit.
Regards,
Asif Nurie [deceased]
- New Delhi, India
With deep regret we sadly advise that Asif passed away on Jan 24, 2016
2004
Q. What exactly is "Black Chrome"?
And what is the plating process?
I'm looking into plating saltwater fishing lures,brass material.
- BRISTOL, Pennsylvania
August 29, 2009
A. Hi, Steve. Black chrome is regular chrome plating to which has been added a contaminant which makes the plating come out smokey or black. You can read what is involved in chrome plating in our Chrome Plating Tutorial, and you can listen to a podcast about black chrome plating. You can also search the site for threads about black chrome. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
August 31, 2009
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