Effect of Ag addition in Sn on growth of SnTe compound during reaction between molten solder and tellurium

SnTe is the most common compound formed at the bismuth telluride/metal soldered junction of thermoelectric modules. It affects the mechanical and electrical properties of the soldered junction. In the study we investigate the growth of SnTe compound during reaction between molten Sn–3.5Ag solder and tellurium at 250 °C. We found that the growth of SnTe is suppressed by Ag–Te bilayer compounds that block further reaction between liquid Sn and Te. With increasing reaction time, the SnTe morphology becomes rough as a result of coarsening of SnTe grains. The growth of SnTe grains follows the conservative ripening kinetics with the mean particle size proportional to one-third power of reaction time.