High-temperature oxidation of Ti3Al0.5Si0.5C2 compounds between 900 and 1200 °C in air

The layered, machinable quaternary compound, Ti3Al0.5Si0.5C2, was synthesized via the powder metallurgical route, and oxidized between 900 and 1200 °C in air for up to 80 h. The oxidation of Ti3Al0.5Si0.5C2 produced rutile-TiO2, α-Al2O3, and amorphous SiO2, together with the evolution of CO or CO2 gases. The oxide scale consisted primarily of an outer TiO2-rich layer, an intermediate Al2O3 layer, and an inner TiO2-rich layer. Relatively thick scales formed because of the formation of the semi-protective TiO2 and the gaseous escape of carbon.