Thermal expansion of AuIn2

The thermal expansion of AuIn2 gold is of great interest in soldering technology. Indium-containing solders have been used to make gold wire interconnects at low soldering temperature and over time, AuIn2 is formed between the gold wire and the solder due to the high heat of formation and the high inter-metallic diffusion of indium. Hence, the thermal expansion of AuIn2 alloy in comparison with that of the gold wire and the indium-containing solder is critical in determining the integrity of the connection. We present the results of X-ray diffraction measurement of the coefficient of linear expansion of AuIn2 as well as the bulk expansion and density changes over the temperature range of 20-500 °C.