Optimization of Ultra-high Temperature Antioxidation Coating for C/SiC Nozzle

In order to improve the structure of high temperature ablation resistance coating system of C/SiC material in engine nozzles, a gas turbulence nozzle model was established based on the mass, energy conservation and physical property equations. The numerical ablation method was used to calculate the line ablation rate of the nozzle coatings, and the accuracy of the model was verified by finite elements method. A multi-component composite coating system was founded by comparing the antiablation properties of different types of coatings and the compatibility between coatings. We analyzed the ablation behavior and mechanical erosion of the system. It is found that the linear ablation rates of the HfO
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-ZrC-SiC-C/SiC and TaCZrC-SiC-C/SiC quaternary system at 2500K are suitable for engineering usage. The composite coating system of the nozzle is optimized, and the composite coating film system with the lowest ablation rate is selected in most vulnerable areas. HfO
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-ZrC-SiCC/SiC quaternary system is suitable for using in the convergence area of the nozzle, and TaC-ZrC-SiC-C/SiC quaternary system is suitable in the throat expansion areas. The optimized ablation rate of the nozzle composite coating is about 0.18 mm/s at the throat line as the most vulnerable areas.