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PROCESS TO PLATE 416 STAINLESS BAFFLE

WOULD SOMEONE BE KIND ENOUGH TO TELL ME IF THEY KNOW OF A PLATING PROCESS THAT IS IMPERVIOUS, NOT JUST RESISTANT TO PLATING SALTS AND SULFURIC ACIDS. WE HAVE A REQUIREMENT TO PLATE A SMALL BAFFLE TYPE PIECE THAT IS SUBMERGED CONSTANTLY IN SULFURIC ACIDS AND PLATING SALTS. WE ARE CONSIDERING A HARD CHROME PROCESS BUT DON'T KNOW IF THAT WOULD BE IMPERVIOUS OR JUST SOMEWHAT RESISTANT.

LEE WABASH
- RANCHO DOMINGUEZ, California, USA

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Chrome plating is not appropriate because it is cracked and therefore porous. Electroless nickel would resist the sulfuric acid, but "plating salts" is a broad category. It wouldn't be cheap, but gold plating is probably the best answer.

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

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Dear Mr. Wabash:

The answer is not easy but I can say that definitely chrome plating, even hard chrome over 0.001" or more thick will NOT be suitable. As most platers know, chrome plate is so hard and stressed that is always cracked, so it cannot be impervious. On the other hand when you say plating salts there are a vast number of them that alone or combined might prove more aggressive to chrome than to the bare steel (like hydrochloric acid or chlorides). I am a fan of electroless nickel but even the high Phos will only last some months for each mil thick in such an aggressive environment. Lead is chemically resistant to sulfuric acid in most conditions, is malleable, free of internal stress and can be plated thick but again it also has it's cons as chlorides or galvanic corrosion might lead to dissolution and subsequent contamination of the bath could occur.

Guillermo Marrufo
Monterrey, NL, Mexico