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Tin lead coating on nickel substrate

 

Hi,

I am a production engineering section manager. I am involved in the plating process for my company and we have a lots of problems :-)

We use nickel plated leads on our products and we encounter peeling off of plating solder (sn-pb) on our final coating. Can you give me a solution to this problem to make the solder plating bond effectively on the nickel surface or advice me how to remove the contamination on the nickel surface (oxides, etc.)?

I would appreciate your help very much.

Thank you, best regards! Bonnie S. Roxas
Shindengen Philippines - Calamba, Canlubang, Philippines

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Two possible causes of your problem is passivation of the nickel surface between the nickel and solder plating process and the other cause is organic contamination of the nickel deposit. After nickel plating, it is important to have excellent rinsing, but do not allow the rinsing process exceed ten minutes. Nickel can passivate quickly when contact with oxygen. Nickel can even passivate under water. For the organic contamination, try to carbon treat your nickel bath. To have good adhesion, your nickel plate should have a dull matte finish. If you prevent these problems, your adhesion will improve.

Hope this helps! Karl Weyermann
- Lebanon, Kentucky