摘要:
A hypoeutectic 60Te–40Bi alloy in mass percent was designed as a tellurium atom evaporation source instead of pure tellurium for an ultraviolet detection photocathode. The alloy was prepared by slow solidification at about 10
-2 K·s
-1. The microstructure, crystal structure, chemical composition, and crystallographic orientation of each phase in the as-prepared alloy were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction, electron backscatter diffraction, and transmission electron microscopy. The experimental results suggest that the as-prepared 60Te–40Bi alloy consists of primary Bi
2Te
3 and eutectic Bi
2Te
3/Te phases. The primary Bi
2Te
3 phase has the characteristics of faceted growth. The eutectic Bi
2Te
3 phase is encased by the eutectic Te phase in the eutectic structure. The purity of the eutectic Te phase reaches 100wt% owing to the slow solidification. In the eutectic phases, the crystallographic orientation relationship between Bi
2Te
3 and Te is confirmed as 0001
Bi2Te3//1
21
3Te and the direction of Te phase parallel to 11
20
Bi2Te3 is deviated by 18° from N(2
111)
Te.