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Plating Tin onto Aluminum

I was wondering if it is possible to plate tin onto aluminum with out using any other metal as an intermediate step. Every plating company I have contacted has told me that an intermediate step of nickel is required.

Thanks for your help.

Rafal Janik
student - Guelph, Ontario, Canada
2007

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Hi, Rafal. Please describe what you are trying to do and why. Is this a proposed production process for millions of Winnebagos, or a single pin-head sized sensor? While it is generally true that it is difficult to plate onto aluminum without zincate and copper or electroless nickel, it may not be utterly impossible. How important is adhesion? Will it be soldered? Is porosity a problem? Appearance? Maybe this item could be brush plated without other metals. Unfortunately, it is impossible, or nearly so, to answer finishing questions posed in the abstract. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

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2007

Tin is electrodeposited from stannous sulphate and fluoborate solutions, and sodium or potassium stannate solutions. The former are acid; the latter alkaline; both will attack aluminum.

The way that I have heard plating on aluminum is done involves a pretreatment with an immersion zinc plating solution, known as a "zincate." Then, nickel is applied; then the final coating.

Perhaps, the person you are talking to plates tin directly over the zincate. That would be a new one on me. I'd be concerned about poor adhesion and peeling of the tin.

Have a small lot of test parts plated and give them a good inspection, would be my advice.

Dave Wichern
Consultant - The Bronx, New York