Oxidation behaviour of SiC-platelets and particulates-reinforced Al2O3/ZrO2 matrix composites

The oxidation behavior of hot-pressed SiC-platelets and particulates-reinforced Al2O3/ZrO2 composites has been studied in an electric furnace at atmospheric pressure at different temperatures. The mass gain as a result of transformation of SiC into SiO2 is described as a function of oxidation temperature, time and type of SiC. The mass gain up to 1100degreesC was low, but increased strongly at 1350degreesC. The oxidation process follows a parabolic rate at all oxidation temperatures. Oxidation of composites containing SiC-particulates is higher than the corresponding one containing SiC-platelets. The activation energy, obtained in the present investigation, was 297-333 kj/mol. Diffusion of oxygen and carbon monoxide through the matrix and oxide products appeared to be the rate controlling process. The reaction products were aluminosilicate glass phase and mullite as indicated by SEM and EDX. (C) 2003 Kluwer Academic Publishers.