Solderability of Electrodeposited Fe-Ni Alloys with Eutectic SnAgCu Solder

Solderabilities of electrodeposited Fe-Ni alloys with SnAgCu solder were examined by wetting balance measurements and compared to those of pure Ni and pure Fe platings. Excellent solderability was found on the Ni-52Fe plating as both the wetting force and kinetics approached or exceeded those on the pure Ni. However,upon further increase in Fe content to 75 at. pct, the solderability of the alloy was severely degraded even though it was still better than that of the pure Feplating. X-ray photoelectron spectroscopy showed that such a strong dependence of solderability on Fe content is related to the much thinner, incomplete oxide coverage of Ni-rich plating surface.