High-Temperature Oxidation of Y2O3-Doped Al2O3 Matrix Composites Dispersed with Nano-Ni Particles

The oxidation kinetics of Y2O3-doped Al2O3-based composites dispersed with 5 vol% nano-Ni particles was investigated at temperatures ranging from 1200 degrees to 1350 degrees C in air. The oxidized zone consisted of Al2O3 matrix and NiAl2O4, which was an oxidation product and a thin surface NiAl2O4 layer. The growth of the oxidized zone followed a parabolic manner, which means that mass transport in the oxidized zone was the rate-controlling process. Doping of Y2O3 into Al2O3 matrix decreases growth rate of the oxidized zone. The value of the apparent activation energy was 681 kJ/mol, which was larger than that of nondoped Ni/Al2O3 composites.