Influence of Grain Size on Isothermal Oxidation of Fe–33Ni–19Cr Alloy

Abstract

This paper investigates the influence of grain size on isothermal oxidation of Fe-33Ni-19Cr alloy at 850ºC. Heat treatment process was done to alter the average grain size of the samples. Fine grain size promotes higher grain boundary area which acts as a path for ion diffusion. The results revealed that the average grain size increased with increase in heat treatment temperature. The kinetics of oxidation followed the parabolic law which represent diffusion controlled oxide growth rate with fine grain size demonstrated the lowest oxidation rate. Uniform oxide layer was formed on the fine grain surface denote a good protective scale.