Oxidation kinetics and mechanism of a zirconia based composite dispersed with 304L particles

International audienceThe oxidation at 800 °C of 304L particles dispersed in a zirconia ceramic showed behaviour different from that usually observed for 304L. SEM observations revealed inward growth of Cr2O3 nodules and outward growth of an iron-rich (Fe, Cr) mixed oxide scale. The method of jumps indicated first that a rate-determining step was controlling the kinetics, then that oxidation was favoured by an increase of the oxygen partial pressure. Growth mechanisms of both types of oxides were proposed; the Fe–Cr mixed oxide growth accounted for the major part of the mass gain and was controlled by the diffusion of metal vacancies obeying a law