进口中间相沥青碳纤维超高温石墨化处理后的特性分析

Characteristics Analysis of Commercial Mesophase Pitch-Based Carbon Fibers after Ultra-High Temperature Graphitization

对P25、P55及XN-90三种进口中间相沥青碳纤维3000℃石墨化处理前后的微观形貌、晶体尺寸、力学性能、导电导热性能及其抗氧化性能进行了表征。结果表明,三种碳纤维微观结构差异较大,均呈现出较为明显的"指纹"特征。三种碳纤维中XN-90热处理温度最高,晶体尺寸最大,石墨化程度最高,抗氧化性能最好。经过3000℃石墨化处理后,三种碳纤维的晶体尺寸、石墨化程度及导热性能均有较为明显的提高;P25和P55纤维的拉伸强度显著提高,而XN-90纤维的拉伸强度有所降低,这与其石墨化后纤维芯部的孔洞变大有关。

The microstructure,crystalline size,mechanical properties,electrical and thermal conductivity and oxidation resistance of commercial mesophase pitch carbon fibers(P25,P55 and XN-90)were characterized before and after graphitization at 3000℃.The results showed that the microstructure of the three kinds of carbon fibers are quite different,and all of them show obvious‘fingerprint’characteristics.XN-90 has the highest heat treatment temperature,the largest crystal size,the highest graphitization degree and the best oxidation resistance of the three carbon fibers.After graphitization at 3000℃,the crystalline size,graphitization degree and thermal conductivity of the three kinds of carbon fibers are improved obviously.The tensile strength of P25 and P55 fibers increased significantly,while the tensile strength of XN-90 fibers decreased,which was related to the pore enlargement in the core of the fibers after graphitization.