Interfacial reactions in the Sn–In–Zn/Ag and Sn–In–Zn/Ni couples

Sn–In–Zn alloys are promising Pb-free solders. Their interfacial reactions with Ag and Ni substrates at 230 °C are experimentally determined using reaction couple techniques. The reaction path is liquid/ζ/Ag in the Sn–20 wt%In–x wt%Zn/Ag couple when the Zn content is less than 0.7 wt%, and the reaction path changes to liquid/ɛ-AgZn3/γ-Ag5Zn8/ζ-AgZn/Ag when the Zn content is 5 wt%Zn. The reaction path is liquid/Ni3Sn4/Ni when the Zn content is less than 1.0 wt%, and the reaction path becomes liquid/γ-Ni5Zn21/(Ni3Sn4)/Ni when the Zn content is higher than 2.0 wt%. The reaction paths in both two kinds of couples are affected by the Zn addition.