Oxidation Kinetics of Mi-Dispersed MgO Composites at Elevated Temperatures

摘要

Oxidation behavior of MgO-based composites with 5 vol percent Ni particle dispersoid was investigated at temperatures ranging from 1100 to 1300 deg 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.