Abstract: TaC coating on mesophase pitch-based carbon fibers was prepared by sol-gel method. Characteristic functional groups of Ta sol-gel were studied by FT-IR，the microstructure and composition of the prepared TaC coated carbon fibers were characterized by XRD and SEM，and the antioxidation behavior of the coated carbon fibers was studied by thermal gravimetric analysis. Results showed that after being twice coated and thermal treatment at 1600 ℃，the formed TaC coating layer on carbon fibers with a thickness of about 150 nm was continuous，uniform and smooth without big holes，and the coating layer presented large areas of white TaC particles. It was also showed that the initial oxidation temperature of the twice coated carbon fibers was about 250 ℃ higher than that of the uncoated carbon fibers，no obvious weight loss was observed below 800 ℃，and the final oxidation temperature was improved to 870 ℃. Thus，the oxidation resistance of carbon fiber was improved by TaC coating．

摘要： 采用溶胶-凝胶（sol-gel）法在中间相沥青基碳纤维的表面制备了碳化钽（TaC）涂层。运用FTIR对钽溶胶、凝胶的特征基团进行了分析，借助X射线衍射、扫描电镜分析TaC涂层纤维的物相组成和微观结构，并利用热失重研究了涂层对碳纤维抗氧化性能的影响。研究结果表明，经过二次涂层，1600 ℃热处理后，碳纤维表面的TaC涂层均匀致密，无明显孔洞，呈连续的层状结构，涂层厚度约为150 nm，且涂层中存在大面积的白色TaC颗粒。研究结果还表明，二次涂层后碳纤维起始氧化温度比无涂层碳纤维提高了250 ℃，且纤维在800 ℃以下几乎没有明显的失重，氧化终止温度也提高到870 ℃，该涂层提高了碳纤维的抗氧化性能。