Summary for black zinc-iron plating Discussion
Black zinc-iron plating is likely a zinc/iron alloy coating on steel followed by a black chromate, not a true black chrome layer. Chris Snyder asked about a two-component process: a zinc/iron coating on steel and a black chrome-plated layer. Tim Neveau said his shop used Schloetter chemistry for zinc-iron plating and had tested steel parts to 1000 hours in salt spray without white rust. Joe Pons suggested Chris may actually mean zinc/iron plating with black chromate. A later reply explained that zinc-iron alloy plating can offer better corrosion resistance than plain zinc because the alloy content can be adjusted, and that its iron content makes a stable black chromate practical without relying on silver for the black color. The overall advice was that the customer probably wants black chromate over zinc-iron, not black chrome over zinc-iron.
Q. I have been asked to find out Info about a two component process:
– a zinc/iron coating on steel
-a black chrome-plated layer
does anybody have any suggestions
thanks
Chris Snyder
plater – Charlotte, North Carolina
1999
A. Dear Chris,
For Zinc Iron plating we use Chemistry from Schloetter in UK which is very good and we have tested steel parts up to 1000 hours in a salt spray chamber without white rust.
Regards,
Khozem Vahaanwala
Saify Ind
Bengaluru, Karnataka, India
1999
A. We are an auto supplier and we use a zinc-iron plating with a black chromate on some of our fuel rails. It works well for us. The only thing is that this type of plating system will have to be adapted to the new hex chrome restrictions. I am sure a few chemical suppliers will send you some information on their processes if they see your message. If not, I think there is a list of companies who advertise on this site. You could also get a copy of Metal Finishing Magazine [you may qualify for a free subscription] which also has ads for plating suppliers.
Tim Neveau
Rochester Hills, Michigan
1999
A. Chris, You may be referring to zinc/iron plating and black chromate.
Joe Pons
– Greenville, South Carolina
1999
A. I think you are right, Joe.
Chris: Zinc iron is an alloy plating which, like the other zinc alloys, offers greater corrosion resistance than plain zinc because you can adjust the alloy content, and consequently its electrochemical potential, to differ from the substrate by just enough.
A particular advantage of zinc iron is that, due to its iron content, it is practical to apply a stable black chromate that is not dependent upon silver for the black color. My suspicion, and that of several other readers here, is that your customer is not seeking black chrome plating on top of zinc-iron plating, but this black chromate. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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February 26, 2009