反应法制备SiC涂层组成与结构

The Components and Structure of SiC Coating Fabricated by the Reaction Method

采用反应法在C/SiC复合材料表面制备SiC致密涂层,利用XRD分析涂层的组分及晶体结构,利用扫描电镜及金相显微镜观察涂层的断口及表面形貌,并对涂层形成过程进行了分析。结果显示:涂层主要由SiC及少量的游离Si组成,致密不开裂的SiC涂层与C/SiC复合坯体之间有很好的梯度过渡结构;相反,涂层与坯体之间如果没有形成过渡层,涂层会因热残余应力过大而开裂;反应法制备不开裂SiC涂层与CVDSiC涂层有很好的热匹配性,同时在其表面制备的CVDSiC涂层无点缺陷。

SiC coating is prepared successfully on C/SiC ceramic matrix composites by the reaction method. The phase structure and components of the coating are investigated by XRD. The profile and surface micrograph are observed by SEM and optical metallography microscopy,and the forming course of SiC coating is analyzed. The result shows the main component of the coating is SiC and a little of Si. There is a good gradient structure and no obvious interface between the uncracked SiC coating and C/SiC substrate. On the contrary, if there were no gradient structure, the SiC coating would crack because of the great residual stress.The uncracked SiC coating prepared by the reaction method matched with CVD SiC coating excellently. At the same time,the CVD SiC coating fabricated on it has no dot defect.