Co/(Ag-41.0 at.%Sb)1−xCox and Ni/(Ag-41.0 at.%Sb)1−xNix Interfacial Reactions

The Ag-41.0 at.%Sb alloy has a melting point at 485°C and is a suitable braze alloy for mid-temperature joining processes. Co and Ni are frequently used as barrier layer materials. The Co/(Ag-41.0 at.%Sb)1−xCox and Ni/(Ag-41.0 at.%Sb)1−xNix interfacial reactions at 550°C are studied. Two phases, CoSb and CoSb3, are formed in all Co/(Ag-41.0 at.%Sb)1−xCox couples for which the value of x is 0, 0.01, 0.03 and 0.05. CoSb is a thin layer and the reaction region with CoSb3 phase is a thick region in which granular CoSb3 is mixed with the liquid phase. Two phases, Ni5Sb2 and NiSb, are formed in Ni/(Ag-41.0 at.%Sb)1−xNix couples for which the value of x is 0, 0.01 and 0.05. Both Ni5Sb2/NiSb and NiSb/liquid interfaces are planar. The reaction rates in the Co/Ag-Sb and Ni/Ag-Sb couples are high, and the reaction rates in the Ni/Ag-Sb couples are even higher. Doping Co decreases the reaction rates in the Co/(Ag-41.0 at.%Sb)1−xCox couples, but doping Ni has no noticeable effect upon the reaction rates for the Ni/(Ag-41.0 at.%Sb)1−xNix couples.