Effects of Ni-B Addition on Microstructure and Properties of Sn-1.0Ag-0.5Cu Lead-Free Solder

The solder/substrate reactions, for Sn-1.0Ag-0.5Cu, Sn-1.0Ag-0.5Cu-0.05Ni and Sn-1.0Ag-0.5Cu-0.05Ni-0.02B, were evaluated in what concerns the melting temperature, microhardness, morphology of the solder and chemical composition of the interface layer. The phases formed at the interface between the Cu Substrate and a molten lead-free solder were studied with different stage times. The evaluation of their chemical compositions were performed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS).