Folks,

We've just carried out some qualification tests on a socket which was reflow
soldered to a board whose pads were plated with Ni/Au. As far as I know a
'standard' Sn/Pb solder was used.

The results of the salt spray test were not a pretty sight. The solder
joints corroded to a point where, in some cases, the socket fell off the
board.

Is Ni/Au a particularly bad finish for corrosion resistance and, if so, what
would be the best?

Alternatively is Ni/Au generally good but are there any defects in the
plating/pcb that can cause a failure in such a test?

Also, does anyone know if the corrosion resistance of lead free alloys are
better or worse than the Sn/Pb we all know and love?

Thanks,


Eric Christison Msc
Mechanical Engineer
Consumer & Micro Group - Imaging Division
STMicroelectronics
33 Pinkhill
Edinburgh
EH12 7BF
UK

Tel:     +44 (0) 131 336 6165
Fax:    +44 (0) 131 336 6001

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