Research progress of ZrB2-SiC ceramic coating on graphite and C/C composites

Carbon/carbon (C/C) composites are considered as one of the most promising structural materials in aerospace field owing to their excellent mechanical properties at high temperature. However, the oxidation problem at high temperatures in oxidizing environments significantly restricts their practical application. Coating technology is an effective method to improve oxidation resistance of the substrate and ZrB2-SiC ceramic coatings are very suitable as high-temperature protection coatings for C/C composites due to their excellent oxidation resistance, ablation resistance and thermal shock resistance. The microstructure evolution of ZrB2-SiC ceramic coatings during the process of oxidation and ablation was introduced, and the high temperature protective mechanism was clarified. Then, the advantages and disadvantages of the main preparation methods (pack cementation, CVD, plasma spraying) of the coatings were reviewed, and the oxidation resistance and ablation resistance of coatings prepared by different methods were compared. Moreover, in view of the problems existing in the research and application of this coating, such as low density of the coating, uneven distribution of elements, narrow application temperature range and the poor thermal compatibility with the substrate, the modifications research status of the coatings were summarized from the aspects of powder modification and doping modification, and the significance of spray drying and induction plasma spheroidization (IPS) for ZrB2-SiC powders to improve the performance of plasma sprayed coatings was emphasized. Finally, the main problems and future development directions of this coating system were pointed out from the aspects of coating preparation, structure design, modification and performance test. © 2020, Chongqing Wujiu Periodicals Press. All rights reserved.