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Piston Tin Plating Problem

Dear Sir,

We have had problems with adhesion of tin to aluminium pistons in the past plated in an alkaline potassium stanate solution. To overcome the lack of adhesion we air age for twenty minutes directly after removal from the plating solution and before rinsing. An independent study has found that conducting this air aging process can form crystalline deposits on the surface which are thought detrimental to the function of the part. I would like to know what are these deposits likely to be composed of? Are there methods other than air aging capable of increasing tin plate adhesion to a level comparable with that achieved by air aging? We use a simple adhesive tape method to assess adhesion.

Thanks in advance for any assistance you can give

Kind Regards,

Graham Dodd
- Melbourne Victoria Australia

What is your reference for this air aging? I never heard of it. I would revisit your parameters of tin plating on aluminum for a permanent fix of the problem.

Tom Pullizzi
Falls Township, Pennsylvania

Thanks for the response Tom. Like many "great" discoveries this one was made by accident when several pistons were removed from the plating cell before the final rinse. There is some doubt whether the practice of air aging will continue as indications are that deposits on the piston may be detrimental to the end function of the piston.

Graham Dodd
- Melbourne, Australia

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