Oxidation Kinetics of Ni-Dispersed MgO Composites at Elevated Temperatures

摘要

Oxidation behavior of MgO-based composites with 5 vol% Ni particle dispersoid was investigated at temperatures ranging from 1100 to 1300deg C in air.Oxidized zone consisted of(Mg,Ni)O solid solution and included voids.Growth kinetics of the oxidized zone followed a parabolic law,which meant that mass transport in the oxidized zone was the rate-controlling process.An oxidation model of Ni-dispersed MgO composites was established as a basis of cation diffusion via vacancy diffusion with defect chemistry of formation of cation vacancy in the MgO-NiO system.The parabolic rate constant and its apparent activation energy estimated from the proposed model agreed with experimental results.