The kinetics and interface microstructure evolution in the internal oxidation of Ag–3at.%Sn alloy

•The kinetics and microstructures of internal oxidation of Ag–3at.%Sn alloy has been investigated.•The function of local oxygen partial pressure within the internal oxidized Ag–3at.%Sn alloy has been derived.•The evolution of Ag/SnO2 interface structures in internal oxidization of Ag–3at.%Sn alloy has been quantitatively clarified.

Based on theoretical analysis of internal oxidation kinetics, the local oxygen partial pressure within the internal oxidized Ag–3at.%Sn alloy was derived as a function of the ambient oxidization parameters firstly. Further combined with the interface structure stability diagram, the evolution of Ag/SnO2 interface structures in internal oxidization of Ag–3at.%Sn alloy has been quantitatively clarified. The prediction results indicates that the stoichiometric Ag/SnO2 interface dominates in internal oxidation of Ag–3at.%Sn alloy in air atmosphere at 973 K, while a gradient structures with both O-rich and stoichiometric interface were formed at the condition of 3 atm pure oxygen atmosphere at 873 K.