The Oxidation Behaviour of TiC Matrix Ni3Al and Fe40Al Toughened Composites at High Temperatures

Abstract

High temperature oxidation of TiC ceramic matrix Fe40Al and Ni3Al toughened composites (Fe40Al/TiC, Ni3Al/TiC) of different TiC contents, made by pressureless melt infiltration, was investigated. Oxidation experiments were conducted in air for up to 65 hours at 700-1100°C. Weight gains of the composites showed that Fe40Al/TiC is more oxidation resistant than Ni3Al/TiC ones. SEM/EDS and X-ray diffraction showed that the dense oxidation layers of the two types of composites are mainly composed of crystalline TiO2. The growth of the oxidation layer follows parabolic passive oxidation kinetics, the calculated values of the activation energy of the oxidation mechanism being 270-280kJ.mol-1 and 240-250kJ.mol-1 for Fe40Al/TiC and Ni3Al/TiC, respectively. Al2O3 and Ni-rich phases were also detected in the oxidation layer of Fe40Al/TiC and Ni3Al/TiC, respectively.