Ternary Sn-Zn-Ni alloys were prepared and equilibrated at 250℃for 4-15 weeks.The phases formed in these equilibrated alloys were determined experimentally.The isothermal section of Sn-Zn-Ni system was constructed,based on the phase diagrams of the three constituent binary systems and the ternary phase equilibria data,determined in this study and referenced in literatures.12 single-phase regions were identified in the Sn-Zn-Ni ternary system at 250℃,including the three ternary compounds,δ,τ_1 andτ_2.There were 13 ternary phase regions and 23 binary phase regions in the 250℃Sn-Zn-Ni isothermal section.The solubility of Zn in the binary Sn-Ni compounds is significant,and is 15.1%(mole fraction) in the Ni_3Sn phase. Ternary Sn-Zn-Ni alloys were prepared and equilibrated at 250 ° C for 4-15 weeks. These are formed in these equilibrated alloys were determined experimentally. The isothermal section of Sn-Zn-Ni system was constructed, based on the phase diagrams of the three constituent binary systems and the ternary phase equilibria data, determined in this study and referenced in literatures. 12 single-phase regions were identified in the Sn-Zn-Ni ternary system at 250 ° C., including the three ternary compounds, δ, andτ_2.There were 13 ternary phase regions and 23 binary phase regions in the 250 ℃ Sn-Zn-Ni isothermal section. The solubility of Zn in the binary Sn-Ni compounds was significant and was 15.1% (mole fraction) in the Ni_3Sn phase.