ZrB2-SiC改性C/C复合材料的组织结构控制及氧化烧蚀性能研究

In order to resolve the oxidation problem of carbon/carbon (C/C) composites, a novel modified C/C composites was proposed including ZrB2-SiC modified matrixes and ZrB2-SiC based surface coating. The first step is to prepare ZrB2-SiC modified C/C composites by chemical vapor infiltration and precursor infiltration pyrolysis. The organization structure of each matrix component was controlled by adjusting process parameter, the effect of microstructure on preparation efficiency, mechanical properties, thermophysical properties, oxidation and ablation properties will be studied. Then, the ZrB2-SiC based composite coating is prepared by pace cementation, supersonic plasma spraying and chemical vapor deposition on the surface of modified composites. The preparation process and formation mechanism of coated composites will be studied, the inner law to improve the bonding strength between the modified matrix and coating will be explored, and the relation between organization structure and ablation properties of composites will be established. Additionally, the oxidation and ablation mechanism of coated composites under various service environments will be discussed. The research results can provide theory support for widening the application of C/C composites in ultra-high temperature and high-speed air flow washout field.

本项目针对碳/碳（C/C）复合材料高温易氧化难题，提出并开发一种新型ZrB2-SiC基体改性和ZrB2-SiC基表面涂层结合的改性C/C复合材料,即首先化学气相渗透结合先驱体转化法制备ZrB2-SiC基体改性，研究各基体组元的组织结构对材料制备效率、力学性能、热物理性能及氧化烧蚀性能的影响。然后在改性复合材料表面采用包埋法、超音速等离子喷涂法结合化学气相沉积工艺制备ZrB2-SiC基复合涂层，系统且深入的研究涂层复合材料的制备工艺条件和形成机理，探索提高改性基体与涂层之间结合强度的内在规律，确立涂层复合材料的组织结构同材料氧化烧蚀性能之间的关系，探讨涂层复合材料在多种服役环境下的氧化烧蚀机理，为拓宽改性C/C复合材料在超高温高速气流冲刷环境下的应用奠定理论基础。

本项目针对碳/碳（C/C）复合材料高温易氧化难题，利用基体改性结合表面涂层技术，提出并开发一种新型ZrB2-SiC基体改性和ZrB2-SiC基表面涂层结合的改性C/C复合材料。在该基金项目的支持下，完成了项目计划书规定的研究内容，主要包括：系统研究了热解炭结构和ZrB2含量等对复合材料微观结构、氧化及烧蚀性能的影响，确定了涂层组织结构与材料氧化烧蚀性能的关系，揭示了防氧化体系在多种服役环境下的氧化烧蚀机理。确定出初始C/C多孔预制体密度约为1.0-1.2g/cm3时，所制备复合材料的抗氧化和抗烧蚀性能较优，引入ZrB2组元含量约为15 wt.%时，复合材料在2000℃烧蚀180s后，质量烧蚀率和线烧蚀仅为0.0625mg/s和2.45μm/s。随着烧蚀温度的提高，材料失效原因从以氧化损伤为主转变为以机械剥蚀为主。制备的ZrB2-SiC基复合涂层在1500℃静态空气下氧化200 h保持氧化增重，热震后力学性能出现小幅增加，良好的氧化烧蚀性能得益于氧化过程中复合高温稳定氧化薄膜的形成。该项目的研究成果可为拓宽C/C复合材料作为航空发动机热结构材料的应用奠定一定的理论基础。