炭/炭复合材料SiC/Mo（Six、Al1-x）2抗氧化涂层

摘要

SiC/Mo(Six, Al1-x)2 multilayer coatings were prepared on carbon/carbon (C/C) composites using a multi-phase reac-tion technique to improve their high temperature oxidation resistance. The microstructure and phase compositions of the multilayer coatings were investigated by SEM, XRD and EDS. The coating exhibits a binary-layer microstructure, i. e. an outer Mo ( Six , Al1-x ) 2 layer and an inner SiC layer with a small amount of Mo4. 8 Si3 C0. 6 . The oxidation behavior of the coated C/C composites was evaluated in a supersonic flow of about 1 500 m·s-1 at 1 800 K in a wind tunnel. No destruction of the coated C/C composites was found after 4s oxidation after 24 exposures and thermal cycling between room temperature and 2550K for 24 times in air. The excel-lent oxidation resistance and thermal shock resistance are attributed to a high cohesion between the layers and the C/C composite, and the formation of a continuous and stable glassy film consisting of SiO2 and Al2 O3 on the coated layers during oxidation.%为了提高炭/炭(C/C)复合材料的高温抗氧化性能,应用多相反应技术在C/C复合材料表面制备SiC/Mo(Six、Al1-x )2复合涂层。利用扫描电镜、电子能谱、X射线衍射仪等测试手段对涂层材料的微观结构和物相组成进行分析,同时研究涂层C/C复合材料在超音速气流中的抗氧化性能。结果表明,C/C复合材料表面形成的抗氧化涂层显示出明显的双层结构,从外向内分别为Mo(Six、Al1-x)2与SiC的复合层和纯SiC层,同时有少量的Mo4.8Si3C0.6存在于涂层中。在温度为1800K、气体速率1500m/s的超音速气流中氧化冲刷96s,以及在2550K和室温下热循环24次的测试条件下,制备的SiC/Mo(Six、Al1-x )2涂层材料均未发生破坏现象。涂层材料优良的抗氧化性能和抗热震性能主要归因于基体C/C复合材料的高强度以及在氧化过程中材料表面形成的连续稳定的SiO2和Al2 O3玻璃相。