Effect of mullite coating film on oxidation resistance of carbon materials with SiC-gradient

The oxidation resistance of SiC-gradient carbon materials coated with a mullite film were studied from 600 to 1600 °C. The oxidation resistance tests were carried out in an electric thermobalance with a sensitivity of ±0.1 mg under flowing air with a rate of 200 cm3 min-1. The mass loss per unit area of the initial surface of the substrates were measured as functions of oxidation time and temperature. The surface of the substrates after oxidation was analyzed by X-ray diffraction analysis, and an energy-dispersive X-ray analyzer was used to examine the chemical compositions of mullite thin films after the oxidation tests.