Stability of an alloy/oxide interface with oxygen ions being the dominant diffusing species in the oxide scale

Abstract

The criterion for interfacial stability between an alloy and its oxide was formulated by Wagner [ J. electrochem. Soc. 103, 571 (1956)] for the specific case when the cations are the diffusing species in the oxide scale. However, for the oxidation of (Pb, In) and (Pb, Sn) alloys, oxygen in the predominant diffusing species in the oxide scales. The criterion formulated by Wagner is no longer applicable. In the present study, the criterion was formulated for the case when oxygen ions are the dominant diffusing species, following the approach used by Wagner. The criterion was used to determine the interfacial stability of (Pb, In)/In 2O 3. In order to determine the (Pb, In)/In 2O 3 interfacial stability, it is necessary to know the interdiffusion coefficient of (Pb, In) and the intrinsic diffusion coefficient of oxygen in In 2O 3. Intrinsic diffusion coefficients for In 2O 3 are not available and are estimated from the parabolic rate constants for the oxidation of (Pb, In) alloys. Calculations using the interdiffusion coefficient of (Pb, In) from the literature and the estimated intrinsic diffusivity of oxygen indicated that the (Pb, In)/In 2O 3 interface should be planar.