Role of SiC nanowire coating on oxidation behavior of carbon fibers: Kinetic and thermodynamic study

The oxidation kinetics of SiC nanowire coated carbon fibers in oxygen atmosphere were studied through isothermal thermo-gravimetric analysis and dynamic thermo-gravimetric analysis. The isothermal weight loss curve showed two activation energies for the oxidation of SiC nanowire coated carbon fibers. The oxidation process was reaction controlled below 923 K with an activation energy of 125 kJ mol− 1 and mixed controlled (gas diffusion and reaction) above 923 K with an activation energy of 28 kJ mol− 1. Under non-isothermal condition the oxidation mechanism followed three-dimensional diffusion obeying the Zhuravlev–Lesokhin–Tempelʹman mechanism with differential form F(α) = 1.5(1 − a)4/3[(1 − a)− 1/3 − 1]− 1 and integral form G(α) = [(1 − a)− 1/3 − 1]2. The kinetic and thermodynamic parameters were evaluated and correlated with surface induced oxidation mechanism.