Investigation of isothermal and no-isothermal oxidation of SiC powder using an analytic kinetic model

The oxidation of SiC powder has been investigated under non-isothermal and isothermal conditions. X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM) were employed to investigate the morphological development during the oxidation. The results show that the major oxidation product was amorphous silica and the oxidation reaction was mainly diffusion-controlled. Based on limited experimental data, an analytic kinetic model, which expresses the oxidation weight gain as a function of time and temperature explicitly, has been used to predict the oxidation behavior of SiC powder. The comparison between experimental results and theoretical calculation shows that this new model works very well. The activation energy of non-isothermal and isothermal oxidation of SiC powder has been derived to be 226.5 kJ/mol and 187.5 kJ/mol, respectively.