A study on the oxidation kinetics and mechanism of three-dimensional (3D) carbon fiber braid coated by gradient SiC

The oxidation kinetics and mechanism of gradient SiC coating/3D carbon fiber braid (coated braid, CB) in static air were studied through isothermal oxidation-weight loss, non-isothermal thermogravimetric (TG) and differential thermogravimetric (DTG) also. The results showed that the oxidation process of CB in isothermal condition was reaction-controlled in the first step and, gas diffusion and reaction-controlled in the second step. In non-isothermal condition, the characteristic of oxidation process was self-catalytic. The oxidation mechanism was one-dimensional diffusion. The kinetic parameters were: log A (min^-1) = 10.12 and E_a (kJ mol^-1) = 224.96.