Phase Formation and Diffusivity in the Ternary Cu-Zn-In System

Formation of the phases in Cu-Zn-In system was investigated by means of diffusion multiples annealed in isothermal conditions. The annealing of three different configurations of joints was performed at increasing temperatures (130, 350, 450 °C): below and above melting temperature of In and above Zn melting temperature. It was found that In revealed the ability for the preferential diffusion in Zn along the grain boundaries, forming the eutectic phase. In all applied temperatures, pure Cu was the barrier for the diffusion of In, while the diffusion of Zn proceeded easily, leading to the formation of binary CuZn phases; the phases from the Cu-In system were not found. The ternary Cu-Zn-In phases were formed at temperatures of 350 and 450 °C, at which the simultaneous diffusion of In and Zn in Cu took place, with participation of liquid In and Zn. The obtained results are the starting point for the calculation of the Cu-Zn-In phase diagram which remains unavailable, in spite of fact that all Cu-Zn, In-Zn and Cu-In binary diagrams are well known.