Characterization of coating cracks in oxidation-resistant SiC coating on C C composites

Oxidation behavior of the SiC-coated C/C composites and cracking behavior of the SiC coating were discussed. In the oxygen diffusion controlling temperature range, an analytical model was developed for the prediction of weight loss due to oxidation of the SiC-coated CIC composites. This model was derived from the consideration of the oxygen diffusion through the coating cracks. The oxidation rate based on this model is in fairly good agreement with the experimental results. To make the model self-consistent, an FEM model for the prediction of the spacing and width of the coating cracks was then proposed. The predictions by this model agreed with that of experimental observation as a function of coating thickness, coating treatment temperature.