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High temperature zinc plating application

Q I am looking forward for zinc plating treatment for a component made up of mild steel my application asks for temperature resistance of 250 °C to 30 °C in a cyclic mode cycle time is approximate 1/2 an hour. which type of zinc plating and process can suit these requirements so that the chipping off of the metal does not happen in the service life of 3 years.

rajesh sampat
ate - ahmedabad,gujarat , India
1999

I would't try to use zinc for such an application especially in humid environments in India. It will likely fail within a few months.

Mandar Sunthankar
- Fort Collins, Colorado
1999

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Rajesh,

Zinc melts at 420 degrees C., and softens very appreciably by 150 °C., so there may be some issues of applicability based on the temperature. But you need not worry about properly plated zinc of any type "chipping off".

I don't think I agree with you, Mandar. If this is, as it sounds, an application where the coating is subjected to the possibility of "chipping off", it sounds like there may be a good possibility of scratches. And if scratches sound likely, what better way to protect a steel component than coat it with zinc?

Ted Mooney, P.E.
Striving to live Aloha
(Ted can offer longterm or instant help)
finishing.com - Pine Beach, New Jersey

Ted, my concern is more of corrosion in high (80 to 100%) humidity plus polluted air in India rather than wear or chipping. On top of that, scratches could make it worse. And again, with 250 to 30 °C cyclic mode, no use of chromate either. Maybe galvanizing will be better compared to plating. To me, chrome or nickel plating sounds better for a three year life.

Mandar Sunthankar
- Fort Collins, Colorado
1999

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Mandar, I understand your reasoning and don't disagree with it to a point. Nickel-chromium is a barrier layer plating and ideal as long as the application is such that it won't get scratched through; once scratched through, it is useless. Zinc is a sacrificial plating that does indeed corrode, and perhaps pretty rapidly; but it protects the substrate even if compromised all the way to the point where steel is exposed.

Ted Mooney, P.E.
Striving to live Aloha
(Ted can offer longterm or instant help)
finishing.com - Pine Beach, New Jersey

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