Corrosion problems of SAC-SiC composite solder alloys

Abstract

SiC nano-fibers and nano-particles in 0.5 wt% were mixed into SAC0307 alloy. Solder joints were stored for 4000 h in 85 °C/85RH%. The SiC nano-phases decreased the corrosion resistance of the composite solder alloys and increased the Sn whisker growth. Microstructural analysis with SEM and FIB proved that whisker growth was caused by localized corrosion and intermetallic layer growth at the upper meniscus of the solder joints, which effects caused mechanical stress via volumetric changes. DFT simulations proved that although SiC could bond to Sn atoms, but the SiC is prone to corrosion, so SiC acted as corrosion incubation points in the Sn-matrix.