涡流增强CVI制备C/Cx-SiCy复合材料的沉积机理与抗氧化性能研究

随着飞行器制造技术的发展，我国对超高温、耐烧蚀、抗氧化、大尺寸异形热结构件的需求越来越急迫。具有密度低、高温力学性能优异等特点的C/C复合材料，无疑是制备此类构件有力的竞争者，但是C/C复合材料的抗氧化性能欠佳，为此本项目拟采用涡流增强CVI共沉积的全新方式，制备具有成分梯度的SiC改性的C/C复合材料，即C/Cx-SiCy复合材料。通过创新地在CVI过程中引入涡流，大幅增强预制体边界层物质交换速率，以达到降低复合材料孔隙率的目的。本项目将量化流体对共沉积CVI过程的影响，研究涡流流体CVI共沉积机理。同时，控制C/Cx-SiCy复合材料中的成分梯度，在保有常规C/C复合材料优异高温力学性能的同时，还具备良好的抗氧化性能，提升材料结构的寿命。本项目将解决流体力学描述下CVI过程的工艺革新和技术瓶颈，为高密度C/C复合材料的抗氧化研究提供全新的解决方案。

As the development of the high speed aircraft, the need for large scale special shaped material with high temperature, anti ablation, anti-oxidation properties has grown quickly in our country. C/C composite is a great competitor as it is low density and has high mechanical strength in high temperature. However, the anti-oxidation property is unsatisfactory. Therefore, the project proposed a new CVI technique assisted with vortex to fabricate C/C composite that is modified by gradient SiC, i.e., C/Cx-SiCy composite. By introducing strong vortex during the chemical vapor infiltration process, the mass exchange is energized near the boundary layer so that it can increase the density and lower the porosity. The project will quantify the influence that fluid does to the CVI process, and study the co-deposition mechanism of the CVI process. At the same time, the project seeks to control the composition gradient of C/Cx-SiCy composite that maintains high mechanical strength while having good anti-oxidation property and extend its life-span. The project will ultimately solve the technique bottleneck for CVI and incorporate fluid dynamics into traditional CVI paradigm, thus offers a new solution for anti-oxidation research of high density C/C composite.