Metal finishing Q&As since 1989

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Black hard chrome problems

Hi,
We are a hard chrome plating shop that are trying to get a black chrome line set up.
The deposits seem to come out soft and polish off easily but leave the hard chrome surface underneath tinted a different color. The Bath we are using is made up of 32 oz per gallon of chromic acid, 28oz per gallon of Glacial acetic acid [on eBay or Amazon] 99%, and 1 oz per gallon Barium acetate. Air agitation is being used and various bath temps have been used between 75 and 100 degrees fahrenheit. Plating was done at 6 to 9 volts for up to 1/2 hour.
Anyone with any ideas or help would be greatly appreciated.
Thanks,

Allan Rothspan

2006

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June 13, 2008

I am having hard chrome plating unit with grinding shop.
I want to establish black hard chrome plating plant.
how can I proceed? Will you assist me?reply.

Parag Shah

Black chrome is a decorative process that is very thin. Thick coatings are not possible because you are using a "poisoned" bath to plate from. It is more durable than black nickel, but it will not stand up to the abuse that regular hard chrome does.

James Watts
Navarre, Florida
June 16, 2008