Preparation and Property of Novel-Type Au-19.25Ag-12.80Ge Solder Alloy

According to Au-Ag-Ge phase diagram, a novel-type Au-19.25Ag-12.80Ge (mass fraction,%) solder alloy was prepared. The melting characteristic and microstructure of the solder was analyzed by DTA and scanning electron microscope, and its wettability with pure Ni was also studied. The results show that its melting temperature range is 446.76–494.40 °C, and the temperature interval between the solidus and the liquidus is 47.64 °C. When the soldering temperature is in the range of 510–550 °C, the solder alloy has a good wettability with Ni and a wetting ring appears. The interface structure observation reveals that there is one obvious diffusion layer between the solder alloy and base metal; X-ray energy spectrum analysis results show that the diffusion layer is Ge-Ni intermetallics. Thin strip solder alloy with a thickness of 0.1 mm can be prepared by the technique of hot-rolling after coated with aluminum alloy then cold-rolling together with intermediate annealing.