【摘要】 采用放电等离子烧结（spark plasma sintering,SPS）工艺制备碳纤维增强碳化硼（C_f/B₄C）复合材料，通过X射线衍射和激光拉曼光谱对聚丙烯腈（polyacrylonitrile,PAN）基碳纤维石墨化度进行表征，重点研究烧结温度、烧结压力和保温时间对碳纤维石墨化的影响。结果表明，温度、压力和保温时间均对碳纤维石墨化有影响，其中烧结温度的影响最明显。烧结温度为2 000℃时，碳纤维的（002）晶面间距d（002）和拉曼光谱中D峰强度I_D与G峰强度I_G的比值分别为0.336 nm和0.377，石墨化度达到92.21%。根据XRD所测的石墨化度和拉曼光谱中R^-1的对应关系，拟合得到拉曼光谱表征碳纤维石墨化度的公式。SPS下PAN基碳纤维的低温石墨化是由于SPS综合了温度、压力和电流的影响，以溶解-再析出为主要催化机理，其中界面活化程度或许是产生碳纤维石墨化度差异的根本原因。更多还原

【Abstract】 In this paper,the C_f/B₄C composites were fabricated by spark plasma sintering （SPS）.The graphitization degree of polyacrylonitrile （PAN） carbon fibers was characterized by X-ray diffraction and Laser Raman spectroscopy.The effects of sintering temperature,sintering pressure and holding time on the graphitization of carbon fibers were focused on.The results show that temperature,pressure and holding time have certain effects on the graphitization of carbon fibers,and the effect of temperature is the most obvious.When the sintering temperature reaches 2 000℃,the crystal plane spacing d（002） of carbon fiber by XRD and Raman peak intensity ratio （I_D/I_G） is 0.336 nm and 0.377respectively,and the graphitization degree of carbon fibers reaches 92.21%.According to the corresponding relationship between the graphitization degree measured by XRD and Raman spectrum,the graphitization degree formula of carbon fibers characterized by Raman spectrum is fitted.The low-temperature graphitization of PAN carbon fibers under SPS is due to the fact that SPS combines the influences of temperature,pressure and current.In addition,the main catalytic mechanism is dissolution and reprecipitation.The difference of interfacial activation may be the fundamental reason for the different graphitization degree of carbon fibers.更多还原