SiCf/SiC复合材料的硅酸钇改性机理及其高温水氧腐蚀行为

SiCf/SiC composites are developed in many countries as the key thermal structure material for they possess some excellent properties such as high-temperature resistance, low density, high strength. However, serious water-oxygen corrosion always occurs when the composite is used in high-temperature water-oxygen environment for a long time such as aviation engines, which leads to the reduction of lifetime. The environmental barrier coating (EBC) can effectively improve the lifetime of SiCf/SiC materials, but there are still some problems affecting the lifetime such as high sintering temperature, low density and easy to peel off. At the same time, the corrosion resistance of interphase and matrix in this composites should also been improved. Therefore, this project proposes that use corrosion-resistant yttrium silicate (Y2Si2O7) prepared by chemical vapor reaction to modify the matrix and interface of SiCf/SiC composites. We aim to resolve the following basic scientific issues, such as vapor deposition reaction mechanism of Y2Si2O7 ceramic, strengthening and toughening mechanism and optimum design of interface, and water-oxygen corrosion mechanism of SiCf/SiC composites modified by Y2Si2O7 ceramic, which will provide theory and technology foundation for the development of SiCf/SiC composites. The research achievements of this project will contribute to improve the water-oxygen corrosion resistance and lifetime of domestic SiCf/SiC composites, accelerate their engineering applications. Meanwhile, the theory and technology of modification process of ceramic matrix composites will be enriched and developed.

SiCf/SiC材料具有耐高温、低密度、高强度等性能优势，是各国竞相发展的关键热结构材料。但该材料在高温水氧环境中易发生水氧腐蚀失效，影响其在高推比航空发动机等领域长寿命使用。环境屏障涂层（EBC）可有效提高SiCf/SiC材料使用寿命，但仍存在烧结温度高、致密度低或易剥落等问题，应同时提高SiCf/SiC材料基体及界面的耐腐蚀性。为此，本项目提出采用化学气相反应制备耐腐蚀硅酸钇（Y2Si2O7）对SiCf/SiC材料的界面和基体进行改性，解决Y2Si2O7陶瓷的气相反应沉积机制、界面优化设计与强韧化机制以及Y2Si2O7陶瓷改性SiCf/SiC材料的抗水氧腐蚀机理等基础科学问题，为发展抗水氧腐蚀SiCf/SiC材料提供理论和工艺技术基础。本项目研究成果将有助于提高我国SiCf/SiC材料的抗水氧腐蚀性能和使用寿命，加速该材料工程应用。同时将丰富和发展陶瓷基复合材料的改性工艺理论与方法。

SiCf/SiC材料具有耐高温、低密度、高强度等性能优势，是各国竞相发展的关键热结构材料。但该材料在高温水氧环境中易发生水氧腐蚀失效，影响其在高推比航空发动机等领域长寿命使用。环境屏障涂层（EBC）可有效提高SiCf/SiC材料使用寿命，但仍存在烧结温度高、致密度低或易剥落等问题，应同时提高SiCf/SiC材料基体及界面的耐腐蚀性。为此，本项目采用化学气相反应制备耐腐蚀硅酸钇（Y2Si2O7）对SiCf/SiC材料的界面和基体进行改性，掌握了Y2Si2O7陶瓷的气相反应沉积机制、界面优化设计与强韧化机制以及掌握SiCf/Si-Y-(B-)C复合材料制备工艺与强韧化机制、高温水腐蚀行为与失效机理等基础科学问题，为发展抗水氧腐蚀SiCf/SiC材料提供理论和工艺技术基础。本项目研究成果将有助于提高我国SiCf/SiC材料的抗水氧腐蚀性能和使用寿命，加速该材料工程应用。同时将丰富和发展陶瓷基复合材料的改性工艺理论与方法。