Phase Equilibria of the Sn-Bi-Te Ternary System

Abstract

Bi 2 Te 3 is one of the most promising thermoelectric materials, and Sn is the primary constituent of most electronic solders. Knowledge of phase equilibria of the Sn-Bi-Te ternary system is important for thermoelectric applications. Twenty-seven Sn-Bi-Te alloys were prepared and equilibrated at 160°C and 500°C. The equilibrium phases were determined, and the isothermal sections were constructed based on three binary constituent phase diagrams and ternary phase equilibria results. No ternary compounds were observed in the Sn-SnTe-Bi region. The SnTe phase is very stable and has tie-lines with the Sn, liquid, and Bi phases at 160°C. At 500°C, in addition to the already known SnBi 2 Te 4 and SnBi 4 Te 7 ternary phases, two new ternary compounds (Sn 2 Bi 2 Te 5 and SnBiTe 2 phases) were found. SnTe and Bi 2 Te 3 have significant mutual solubilities, and the ternary compounds SnBi 2 Te 4 , SnBi 4 Te 7 , and Sn 2 Bi 2 Te 5 are all in the SnTe-Bi 2 Te 3 pseudobinary section.

Interfacial Reactions between Sn-Based Solders and n-Type Bi2(Te,Se)3 Thermoelectric Material

“…EPMA analysis revealed the composition of the dark phase as 53.1 at.%Sn-0.2 at.%Bi-3.2 at.%Se-43.5 at.%Te, which was identified as the SnTe phase. Based on the phase equilibria of the Sn-Bi-Te system and the Se-Sn-Te system [25][26][27], the solubilities of Bi and Se in the SnTe phase at 250 • C is about 10 at.%Bi and 4at.%Se, respectively, consistent with the observed composition of SnTe in the interfacial reactions. The bright phase contained 4.1 at.%Sn-49.7 at.%Bi-3.8 at.%Se-42.4 at.%Te, suggesting that it was the BiTe phase with ~4 at.%Sn and ~4 at.%Se solubilities.…”

SYNTHESIS AND CRYSTAL STRUCTURE OFA NEW 9P–TYPE LAYERED van der WAALSCOMPOUND SnBi4Te4

“…The Sn-Bi-Te ternary system [21][22][23]has been studied by various groups of authors so far [21][22][23]. According to Karpinski [21], this system includes three stable ternary compounds, namely SnBi 2 Te 4 , SnBi 4 Te 7 , SnBi 6 Te 10 which are melt by peritectic reactions at 873, 863 and 855 K, respectively.…”

“…According to Karpinski [21], this system includes three stable ternary compounds, namely SnBi 2 Te 4 , SnBi 4 Te 7 , SnBi 6 Te 10 which are melt by peritectic reactions at 873, 863 and 855 K, respectively. Later, Kuropatwa [22] and Chiu [23] independently have reported an additional two ternary compounds -Sn 2 Bi 2 Te 5 and SnBiTe 2 . Literature data show that, in order to overcome metastable state, annealing at higher than 700 CHEMICAL PROBLEMS 2020 no.…”