Phase Equilibria of the Sn-Ni-W Ternary System at 750°C

Ni is commonly used as a barrier layer due to its lower reactivity with solders which combine with Sn. W can be used as a minor to reduce the intermetallic compounds (IMCs) material. Phase equilibria information plays a vital role to understand interfacial reaction. However, no phase diagram data of Ni-Sn-W is available in the literature. In this study, the alloys were experimentally investigated at temperature 750 degrees C for 720 h. Based on these three Ni-Sn, Ni-W and Sn-W binary phase diagrams, the Ni3Sn, Ni3Sn2, Ni3Sn4 and (Sn) phases in the Ni-Sn system, the (Ni), NiW2, NiW, Ni4W and (W) in the Ni-W binary system, and the liquid (L), and (L)+(W), and (W) in the Sn-W system are stable at 750 degrees C. The isothermal section of the Ni-Sn-W ternary system at 750 degrees C is composed of 9 single-phase regions, 13 two-phase regions, and 7 three-phase regions. Meanwhile, no ternary IMCs was found.