Intermetallic compounds formed during the interfacial reactions between liquid In-49Sn solder and Ni substrates

The interfacial reactions between liquid In-49Sn solder and Ni substrates at temperatures ranging from 150°C to 450°C for 15 min to 240 min have been investigated. The intermetallic compounds formed at the In-49Sn/Ni interfaces are identified to be a ternary Ni33In20Sn47 phase using electron-probe microanalysis (EPMA) and x-ray diffraction (XRD) analyses. These interfacial intermetallics grow with increasing reaction time by a diffusion-controlled mechanism. The activation energy calculated from the Arrhenius plot of reaction constants is 56.57 kJ/mol.