耐高温、耐烧蚀SiC陶瓷基复合材料的高效制备及烧损机理

针对空天飞机对可重复使用热防护材料及低成本高效制备技术的迫切需求，申请人提出了SiC陶瓷基复合材料微-纳碳网络基体结构均匀陶瓷化转变的制备新方法。但目前仍缺乏对多孔体结构设计方法、陶瓷化转变动力学机制、长时宽温域烧损机理等关键科学问题的深刻认识。本项目采用控制变量法，通过不同基体与界面多孔体所制C/SiC复合材料性能对比，获得多尺度碳网络基体与多组分碳-陶界面的设计准则；采用分子动力学与第一性原理计算得到纳米尺度液硅浸渗函数及SiC生长机制，结合实验以揭示多孔碳基复合材料均匀陶瓷化转变的反应机制；采用热震、氧化、烧蚀实验方法，阐明SiC陶瓷基复合材料长时宽温域烧损机理，并获得重复使用条件下材料结构-性能演变规律。从而建立低成本、短周期、高性能SiC陶瓷基复合材料的可控制备新方法，形成快速制备大尺寸复杂热结构部件的技术能力，推动型号研制进度，同时为在高铁、钢铁等行业的进一步推广应用奠定基础。

According to the urgent requirements of aerospace planes for reusable thermal protective materials and their low-cost and high-efficiency preparation techniques, the applicant has proposed a new preparation technique for SiC-matrix composites whose principle is uniform ceramization of micro-nano carbon-network structure matrix. However, there is still lack of deep understanding for structure design method of porous precursor, dynamics mechanism of uniform ceramization, ablation mechanism with long-time and wide-temperature range, et al. In this study, C/SiC composites with different properties will be prepared by changing matrix and interface structure of porous precursor, in order to achieve the design criteria of multiscale carbon-network matrix and multicomponent carbon-ceramic interface. The uniform ceramization mechanism can be obtained by investigating the function of liquid silicon infiltration and the growth mechanism of SiC using molecular dynamics and first principles calculations and experimental methods. The ablation mechanism with long-time and wide-temperature range and the structure-performance evolution rules of materials will be investigated by using thermal-shock, oxidation and ablation experimental methods. Through the above investigations, the low-cost, short-cycle preparation technique for high-performance SiC-matrix composites will be established and the manufacturing capacity of large and complex thermal-structure components will be formed, which can be efficient to promote the research progress of aerospace planes. It is also expected that the study will speed up the industrial application of SiC-matrix composites in the field of high speed railway and steel production.