【摘要】 采用Si、C及Al2O3粉末为原料,利用包埋法结合真空热处理在C/C复合材料表面制备SiC涂层。并利用XRD、SEM等测试手段分析真空热处理对涂层C/C复合材料的组织结构和力学性能的影响。研究结果表明:包埋粉料中Si含量为84.5%和87.0%(质量分数)时,所制备的SiC过渡层由β-SiC、α-SiC和Si三相组成。真空热处理可以降低SiC涂层中游离Si的含量,使SiC过渡层形成多孔结构,进而改善SiC涂层C/C复合材料的韧性,获得的涂层最大载荷处挠度可提高6.93%。真空热处理后,C/C复合材料SiC涂层的断裂形式为剪切断裂和纤维拔出断裂的混合形式。更多还原

【Abstract】 SiC coating on carbon-carbon composites was prepared by pack cementation and vacuum heat treatment(VHT).Microstructure and mechanical prosperities of SiC coating were investigated by XRD,SEM etc.The SiC layers prepared by pack cementation with Si contents of 84.5% and 87.0%(mass fraction) composes of β-SiC、α-SiC and Si phases.Part of the Si phase can be evaporated by vacuum heat treatment which results in the formation of porous structure coating.The toughness of C/C composites coated by SiC was improved due to the formation of porous structure of SiC coating after the VHT.The deflection at the maximum load for the SiC coating sample increases of 6.93% more than that of samples without VHT.The fracture way of SiC coated C/C composites is the mixing mode of cutting and fiber pulling out.更多还原