High-Temperature Oxidation of Y_2O_3-Doped Al_2O_3 Matrix Composites Dispersed with Nano-Ni Particles

摘要

The oxidation kinetics of Y_2O_3-doped Al_2O_3-based composites dispersed with 5 vol% nano-Ni particles was investigated at temperatures ranging from 1200° to 1350℃ in air. The oxidized zone consisted of Al_2O_3 matrix and NiAl_2O_4, which was an oxidation product and a thin surface NiAl_2O_4 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 Y_2O_3 into Al_2O_3 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/Al_2O_3 composites.