Morphology and growth kinetics of Ag3Sn during soldering reaction between liquid Sn and an Ag substrate

For the soldering of recycled Ag sputtering targets, the interfacial reaction between liquid Sn and an Ag substrate at temperatures ranging from 250 -425 degreesC has been investigated. Experimental results show that a scallop-shaped layer of Ag3Sn intermetallic compounds formed during the soldering reaction. Kinetics analysis indicated that the growth of such interfacial Ag3Sn intermetallic compounds is diffusion-controlled with activation energy of 70.3kJ/mol. During the reaction, the Ag substrate dissolves into the molten Sn solder and causes the appearance of needle-shaped Ag3Sn precipitates in the Sn matrix.