Optimum design of cadmium-free silver-based filler metal contaed 20%Ag

According the demand of the melting temperature and distribution phase of silver-based filler metal, the content of each element is calculated and optimized by phase diagram, then the result is adjusted and discussed according to the distribution phase and temperature of filler metal, and the optimal range of each element is as following:Ag:19%-20%, Cu:38.2%-42.9%, Zn:31%-33%, Sn:4.5%-6.5%, respectively.By the analysis of microstructure and X-ray diffraction, the silver-based filler metal is consisted of eutectic structure, tin bronze and silver solid solution, and its melting temperature and strength can be equivalent to that of the BAg30CuZnSn filler metal.