I have heard that some platers plate Pd over CuSn to replace Pd over Ni, so to prevent Cu diffusion in brass plating. For the Pd/Cusn combination, the plating can crack easily, and a buffer layer between the two layers might be needed, but what is that buffer layer made of?
WY Wong - Hong Kong 2000
Cobalt plating can be used in place of Nickel plating. No CuSn is required when Cobalt plating is used.
Deville Yiu Sun Lick, Hong Kong, China - Hong Kong 2000
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