Letter 4039

Tin plating on Aluminum 

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I want to plate tin onto aluminum. Can I plate directly onto the aluminum,or is an intermediate coating required? I was planning to degrease, de-ox, and zincate the aluminum prior to plating with tin.

How thick can I plate the tin?

Next, I want to plate tin on a plasma-sprayed tin surface. How do I activate the plasma-sprayed tin to get a good bond?

Thanks,

Wanda Hudson
- Huntsville, Alabama

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You will need some type of strike or barrier coating between the Tin and Aluminum if you want good results. As far as a vendor it depends on the type of tin. For Alkaline Tin you can make it up yourself. Thickness can be up as much as .001" or more without any problems, depending on the application.

Jim Conner
- Salisbury, MD

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The way I would recommend to plate Sn on Al is to pretreat the Al with the std. process cycle, then immersion Sn the Al. The next step is to either bronze plate the Al or Alkaline Cu plate, then Sn plate in either an Alk. Sn or Acid Sn process.

As for activating the plasma Sn I would recommend an acid that will dissolve some Sn, either MSA, methane sulfonic acid, or fluoboric acid. The conc. to use will be about 5% by vol.

George Shahin Atotech USA Inc. Rock Hill, SC

Hi, folks. It sounds like George is speaking of the Alstan® process as an alternative to zincating.

We don't really like to compare a proprietary process to a generic process like zincate, or to compare one proprietary process to another. But I have seen Alstan lines for bus bar and electrical components, and I suppose that since it is a very purpose-designed process, specifically for applying tin to aluminum, that it may well do that job better than zincating, followed by copper plating, followed by tin plating.

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey