LAUSR

Abstract As a key tellurium atoms evaporation source for ultraviolet detection photocathode, the hypoeutectic Te 75 In 25 alloy was prepared by employing a slow solidification speed of about 10 − 2  K/s. The microstructure and chemical composition of the equilibrium phases formed in the as-prepared alloy were studied in this research work. The experimental results show that the as-prepared Te-In alloy was constituted by primary In 2 Te 5 phase and eutectic In 2 Te 5 /Te phases. The eutectic In 2 Te 5 /Te phases are distributed in the grain boundaries of primary In 2 Te 5 phase. With the slow solidification speed, a pure eutectic Te phase without any excessive indium solute was obtained, where Te content of eutectic Te phase is 100 mass%. Moreover, it can be considered that the stress between the In 2 Te 5 and Te phases plays an important role in reducing the tellurium vapor pressure in Te 75 In 25 alloy.