Interfacial reactions between liquid Ga and solid Au

Abstract

• Interfacial reactions between liquid Ga and solid Au were investigated. • Only one intermetallic phase, AuGa 2 , was formed from room temperature to 150 °C. • Time exponents for the AuGa 2 growth were determined to be 0.91–2.01. • Grain boundary diffusion of Ga was assumed to be the rate-determining step for AuGa 2 growth. Interfacial reactions between liquid Ga and solid Au were investigated from room temperature to 150 °C. It was found that only one intermetallic phase, AuGa 2 , was formed at the Ga/Au interface at all temperatures. During storage, the newly formed fresh AuGa 2 phase continuously nucleated and grown at room temperature on the preformed AuGa 2 /Au interface under supercooled liquid Ga. Time exponents for the AuGa 2 growth were measured to be 0.91–1.44 and 2.01 at room temperature to 125 °C and 150 °C, respectively, with an activation energy of 85.4 kJ/mol at 100–150 °C. Diffusion of Ga atoms through the AuGa 2 grain boundaries was assumed to be the rate-determining step for AuGa 2 growth.