Oxyacetylene torch ablation resistance of Co-modified WC coating deposited on C/C composites by supersonic atmosphere plasma spraying

Cobalt (Co) was chosen as an additive to improve the ablation resistance of WC coating for SiC coated C/C composites, SiC modified WC coating and pure WC coating which were prepared and tested for comparative purposes. Results showed that the thermal shock resistance of WCC (WC-10%Co) coating was better than pure WC coating and WCS (WC-10%SiC) coating. Furthermore, the produced oxide layer on WCC coating was found to be more stable due to the reaction of CoO and WO3. As a result, during oxyacetylene torch ablation test, compared with pure WC coating and WCS coating, WCC coating keeps excellent dimensional stability with the linear ablation rate decreased by 67% and 62%, respectively, showing a significant improvement of the ablation resistance.