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Purpose of Topcoat?

What is the purpose of topcoat in plating process?

Is topcoat influence in increase the SST?

RS Sum
buyer - Bangalore
March 28, 2008

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Hi, RS. "Topcoat" could mean different things in different contexts, but maybe you are referring to a topcoat that follows trivalent chromating on zinc and zinc alloy plating processes? Yes, it's purpose is to increase the Salt Spray Time.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March , 2008

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Mr. Sum,
Top-coat, sealer or finigard usually mean the same process of increasing corrosion resistance in SST by sealing passivation layer on zinc deposit. Top-coat is the only real alternative for hexavalent chromium passivation when we want to keep the same level of protection using trivalent chromium. Unfortunately, top-coat is expensive and difficult process, which can significantly change the cost of zinc plating.

Janusz LABEDZ
- Warsaw, Poland
March 31, 2008

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sir,
I am confused regarding ROHS compliance.
is it the only test to confirm that if the material / solution is ROHS compliance, then it has to be non hazardous to nature or human?
or what are the benifits if the solution is ROHS compliance?
please explain...

Sagar deshpande
- India
July 28, 2008

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Hi, Sagar

RoHS is an acronym for Reduction of Hazardous Substances. The context is that the European parliament has placed limitations on how much cadmium, mercury, lead, hexavalent chromium and a few other substances are permitted on a wide range of products that will be sold in or used in Europe. If your product doesn't comply, and is within the range of regulated product lines, it can't be shipped there.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July , 2008