The microstructure and composition of equilibrium phases formed in hypoeutectic Te-In alloy during solidification

As a key tellurium atoms evaporation source for ultraviolet detection photocathode, the hypoeutectic Te75In25 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 In2Te5 phase and eutectic In2Te5/Te phases. The eutectic In2Te5/Te phases are distributed in the grain boundaries of primary In2Te5 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 In2Te5 and Te phases plays an important role in reducing the tellurium vapor pressure in Te(75)ln(25) alloy. (C) 2017 Elsevier Inc. All rights reserved.