Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Best pretreatment for tin plating on aluminum?

Quickstart:
It isn't possible to electroplate directly onto aluminum because it instantly oxidizes. So pretreatment usually includes an immersion in zincate which electrochemically replaces that aluminum oxide, leaving a zinc surface to electroplate onto. Alternatives include analogous proprietary processes like "Bondal" (zinc+nickel) and "Alstan" (all tin).

Q. What do you believe the best process to electroplate tin to an aluminum 6101 alloy to be? I am currently working with the Alstan process with cyanide but if I get funding for a new line I have been thinking about looking into double zincate before the tin.

Halee
- Mississippi
July 23, 2024

Ed. note: This forum enjoys the warm aloha of real names. People who offer their real name may be less likely to engage with those who don't.

A. Hello Halee,

We don't suggest brands or sources in this forum ( huh? why?), but the idea behind the 'all-tin' process was presumably that if you don't need copper or nickel plating before the tin plating, it might be simpler to optimize the pretreatment process for tin plating rather than optimizing it for copper plating. I have seen it very successfully used in a bus bar plating factory where, because they only needed tin plating, why do copper plating first?

On the other hand, if you sometimes do copper plating on the aluminum, it might prove simpler to use a single pretreatment process for both copper and tin plating rather than using two different pretreatment sequences.

One final way to look at it is that if you are getting customer service for the proprietary sequence, it could prove invaluable in time of need; if you are not getting any, why deal with the complications introduced by a proprietary about which, by design, you will never get full info?

Luck & Regards,

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

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