石墨和C/C复合材料表面ZrB2-SiC陶瓷涂层的研究进展

C/C复合材料具有优异的高温力学性能,是航空航天领域最具发展前景的结构材料之一,但在高温含氧环境中的氧化问题严重地限制了其实际应用。涂层技术是提升基体抗氧化能力的有效手段,因ZrB_2-SiC陶瓷涂层具有优异的抗氧化、抗烧蚀、抗热震等性能,非常适合作为C/C复合材料的高温防护涂层。首先,介绍了ZrB_2-SiC陶瓷涂层在氧化和烧蚀过程中组织结构的演变规律,阐明了该涂层的高温防护机理;然后,综述了该涂层的主要制备方法(包埋法、CVD、等离子喷涂)及每种方法的优点与不足,并对不同方法所制备涂层的抗氧化性和抗烧蚀性进行了比较;之后,针对该涂层研究和应用中存在的问题,如涂层致密性差、元素分布不均匀、应用温度范围窄、与基体热匹配性差等,从粉体改性和掺杂改性两方面总结了该涂层的改性研究现状,重点阐述了对ZrB_2-SiC粉末进行喷雾造粒和感应等离子球化处理对于提升等离子喷涂涂层性能的重要意义;最后,从涂层制备、涂层结构设计、涂层改性、涂层性能测试等方面,指出了该涂层体系存在的主要问题和未来的发展方向。

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.