ZrB2基超高温陶瓷粘接用硅树脂胶粘剂的组分设计与界面强韧化机理研究

ZrB2 based ultra-high temperature ceramics with excellent high temperature structural stability are important thermal protection materials for the development of reusable hypersonic vehicles. ZrB2 based ultra-high temperature ceramic components, fabricated by using the bonding method, can be degraded under high temperature and result in the thermal expansion mismatch of the bonding interface, which becomes one of the key issues that restrict its engineering applications. In this project, hybrid silicone resin will be used as matrix, and the thermal stability and interface matching of the adhesive matrix will be improved by optimizing the composition of high temperature film-forming agent, high temperature stabilizer and high temperature structural converter, and by in-situ construction of SiO2-embedded SiCnw binary reinforcement phase at the interface. The high temperature reaction mechanism of adhesive matrix and bonding interface will be clarified by studying the evolution of phase, element and structure of adhesive matrix and bonding interface at high temperature. The interface matching property will be controlled by numerical simulation analysis of bonding interface stress and interface performance research. The strengthening and toughening mechanism of in-situ SiO2-embedded SiCnw binary phase will be revealed by studying the properties, failure mechanism and fracture microstructure of bonding specimens. This research will solve the technical problem of ZrB2-based ultra-high temperature ceramic bonding interface instability at high temperature, and provide theoretical and technical support for the bonding of thermal protection components of hypersonic aircraft in China.

ZrB2基超高温陶瓷具有优异的高温结构稳定性，是发展可重复使用高超声速飞行器重要的热防护材料。通过胶接手段制备ZrB2基超高温陶瓷构件由于在高温条件下胶粘剂基体分解和界面热膨胀失配，成为制约其工程化应用的关键问题。本项目以杂化硅树脂为基体，通过高温成膜剂、高温稳定剂和高温结构转化剂等组分的优化设计，并通过在界面原位构筑SiO2包埋SiCnw增强相的方法，提高胶粘剂基体的热稳定性和胶接界面匹配性。通过胶粘剂基体和胶接界面在高温条件下物相、元素、组织结构演变规律研究，明确胶粘剂基体和胶接界面的高温反应机制；通过界面应力的数值模拟分析和性能研究，掌握界面匹配性的调控方法；通过胶接试件的关键性能、失效机制和断口微观组织结构研究，揭示原位SiO2包埋SiCnw的相强韧化机理。本项目的研究将解决ZrB2基超高温陶瓷胶接界面高温失稳的技术难题，为我国高超声速飞行器热防护构件的连接提供理论和技术支撑。

超高温陶瓷具有优异的高温结构稳定性，是发展可重复使用高超声速飞行器重要的热防护材料。耐高温胶接技术是制备ZrB2基超高温陶瓷构件的重要技术手段。为了提高硅树脂胶粘剂-ZrB2基超高温陶瓷接头高温热稳定性，本项目开展了硅树脂胶粘剂组分设计、界面反应调控与强韧化研究。主要取得了以下研究成果。1）项目完成了耐1500℃硅树脂胶粘剂的组分设计和复配方法，实现了胶粘剂基体高温条件下稳定的陶瓷转化；2）揭示了ZrB2基超高温陶瓷界面反应机制及与胶粘剂粘接机理，并通过活性镍粉，有效抑制了ZrB2基超高温陶瓷胶接界面处的氧化反应，提升了接头的抗氧化性能；3）在ZrB2基超高温陶瓷胶接界面处构筑了SiO2包埋SiCnw增强相，提高了接头的热冲击性能，明晰了其强韧化机理；4）项目成果取得了关键性的工程化应用。硅树脂胶粘剂1500℃时的热失重为5%;ZrB2基超高温陶瓷胶接构件室温和1500℃粘接强度分别为3.8 MPa和53.8 MPa;经20次热振循环后，粘接强度仍有7.8 MPa。本项目的研究为ZrB2基超高温陶瓷胶构件工程化应用及胶接界面稳定性打下了重要基础。在项目支持下，培养博士研究生1名，硕士研究生3名，发表学术论文2篇，申请国家发明专利3篇。