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Blistering of Silver Plating

March 18, 2008

We are EN and Silver Plating 6061 Al.Parts. We bake at 500 F for 1 Hr., no problem.
Our customer for incoming inspection bakes the samr parts on a Hot Plate same temperature, and they blister were the parts touch the Hot Plate.

Is this to severe a test?

B.J. Mason
Plating Shop Owner - Capitol Heught, Maryland

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B.J.,
Hope things are going well for you down there. I've never heard of direct contact baking on a hot plate. The temp is less than one-third the melting point of silver, but you have to wonder how clean is the surface of the hot plate is, and what effect direct contact heat has on porosity of the silver coating. I think the test is too aggressive, and they should bake parts the normal way. Small ovens are not that expensive to buy.

Mark Baker
Process Engineer - Syracuse, New York
March 20, 2008

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March 21, 2008

BJ,

When your customer heats with the hot plate, they are not getting even distribution of the heat. Therefore, the area closest to the heat source is much hotter the mean heat they are measuring. This means that they are heating to a much higher temperature which is localized and not measured by the hot plate i.e. the temperature of the heating coil less the loss of energy to air and the vessel holding the parts.

Hope this helps.

Gene Packman
process supplier - Great Neck, New York