Analytical models for the internal oxidation of a binary alloy that forms oxide precipitates of high stability

Abstract Since the experimental work of Smith on internal oxidation many attempts have been made to quantify the observations. This paper outlines the mathematical development of the extended model starting from the pioneering work of Rhines et al. A proper definition of the mass balance of individual components at the reaction interface predicts the transition behaviour. A proper definition of the convective velocity due to precipitation of oxide of larger molar volume compare to matrix phase in the differential mass balance introduces a volumetric flow towards the exposed surface that explains the outward extrusion of the matrix reported by many researchers.