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Soldering with Electroless nickel

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Soldering with Electroless nickel | 29 November, 2005

I have a pin and sleeve assembly that utilizes a fusible link type of solder, Bi, Cd, Pb and Sn alloy. The pin is gold plated, the sleeve is copper alloy 725. I have had sporadic success with wetting of the sleeve during the reflow process. To improve the consistency of the soldering process, I have transitioned to an electroless nickel plating on the interior of the sleeve. My yields are now at 100%.

Is it possible for the nickel to migrate into the solder overtime? I am concerned that it may interfere with performance characteristics of the fusible solder.


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Soldering with Electroless nickel | 29 November, 2005

The dissolution rate of nickel into tin is a lot slower than that of copper [into tin]. This results in a nickel-tin (Ni3Sn4) intermetallic that is only 0.25-0.75�m thin after a normal soldering process. The Ni-Sn intermetallic compound tends to be more brittle than Sn-Cu compounds. Nevertheless, Ni is often used as a diffusion barrier because of its slow dissolution rate. [EMPHASIS "Intermetallics In Electronic Soldering" 12/04]

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Soldering with Electroless nickel | 30 November, 2005

Thanks Dave!


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