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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
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
finishing.com - Pine Beach, New Jersey