Oxidation Kinetics and Mechanism of SiC Coating/3-dimensional Carbon Fiber Braid

The in situ reaction method was used to prepare SiC coating on 3-D carbon fiber braid (RB). XRD, SEM, isothermal oxidation-weight loss and non-isothermal TG were used to study the oxidation process and oxidation reaction mechanism of SiC coating/3-D carbon fiber braid (CB). The results showed that coating was coated symmetrically and combined well with every fiber of braid. The oxidation process of CB in isothermal condition was reaction-controlled in the first step, gas diffusion and reaction-controlled in the second step. The oxidation process of CB in non-isothermal condition exhibited a self-catalytic characteristic, the oxidation mechanism was random nucleation, the kinetic parameters were: lgA=10.299min-1; Ea=156.29kJ.mol-1.