Computer Simulation of the Diffusional Growth of Ternary Oxide Scales on Binary Alloys

Abstract

A computer solution is made of the equations for growth by ambipolar diffusion of metal of the ternary monoxide scales on Co‐Fe and Co‐Ni alloys. Computations demonstrate that the parabolic scaling rates and the compositional profiles in these scales calculated using independently obtained diffusional and thermodynamic properties of the solid phases in the alloy‐oxide systems are in agreement with the experimental determinations. Results are analyzed for oxidation of Co‐Fe containing up to 10 a/o Fe to at 1473 K in oxygen at and the oxidation of Co‐Ni alloys containing up to 7 a/o Ni to at 1373, 1473, and 1573 K in oxygen at 105 Pa.