Phase equilibria in the Au–Bi–Sn ternary system at temperatures of 80, 125, and 150 °C

Abstract Sn–Bi alloys form some of the common types of Pb-free solders. Au is used as one of the under bump metallization layers due to advantages such as corrosion resistance and anti-oxidation properties. Phase equilibria information plays a vital role in the development of materials technology and serves as an important tool to understand interfacial reactions at heterointerfaces. In this study, the phase equilibria in the Au–Bi–Sn ternary system were experimentally investigated at temperatures of 80, 125, and 150 °C. The results indicated that a ternary phase with a composition of Au 45 – 48 -Bi 36 – 38 -Sn 14–19 (at.%) was found in the Au–Bi–Sn ternary system at these three temperatures.