ZrB2-SiC基超高温陶瓷复合涂层的制备及机理研究

Faced with extremely complex high-temperature environments, high temperature protective properties of high-temperature structural ceramics are important problem for many industrial fields. Currently, the research on high-temperature protective properties of high temperature ceramic mostly depends on the improvement and optimization of materials itself, but it has some limitations. Preparation of ultra-high temperature coating on the surface of ceramic brings a new idea for improving high temperature protective properties. In this study, ZrB2-SiC matrix coating on the surface of ZrC ultra high temperature composite ceramic is prepared by reactive plasma spray and laser technique using Zr-Si-B4C SHS system. During reactive plasma spraying, ZrB2-SiC matrix coating with good interface bonding can be realized by good chemical compatibility between ZrB2-SiC droplet and ZrC and process optimization of spraying. Reaction formation mechanism of ZrB2 and SiC during spraying is studied, and fusion process and interface bonding mechanism between coating and substrate is analyzed. Favorable microstructure and densification of the coating can be achieved by adjusting laser parameters. The relation between laser remelting parameters and microstructure of coating is investigated, and the response behavior between coating and laser is revealed. Based on the project, high-temperature applications of ZrC will be promoted.

面对极其复杂的高温环境，使高温结构陶瓷保持良好的高温防护性能是众多工业领域亟待解决的重要问题。目前针对高温陶瓷高温防护性能问题的研究大多依赖于材料的改进与优化，存在一定的局限性。在陶瓷表面制备超高温涂层进行表面改性，为提高其高温防护性能带来了全新的思路。本项目选用Zr-Si-B4C的SHS体系，采用反应等离子喷涂和激光技术，在ZrC超高温复相陶瓷表面制备ZrB2-SiC基超高温复合涂层。反应等离子喷涂时，利用喷涂产物ZrB2-SiC熔滴和ZrC良好的化学相容性，并通过喷涂工艺优化，制备出界面结合良好的ZrB2-SiC基涂层，研究喷涂过程中ZrB2、SiC反应形成机理，分析涂层与基体间熔合过程和界面结合机制。通过调控激光参数，获得有利的涂层组织结构，实现涂层的致密化，研究激光重熔参数与涂层组织结构的联系，揭示涂层与激光间的响应行为和规律。本项目研究成果为推动ZrC在高温领域的应用奠定基础。