外加磁场下C／C复合材料的Fe—Ni催化石墨化以及性能研究

在Fe—Ni存在下，外加磁场不但可以提高酚醛树脂炭的石墨化度而且对新生成的石墨层也具有很好的导向作用。实验以短切雕N基碳纤维为增强体，酚醛树脂为基体碳源，采用液相浸渍的方法制备c／c复合材料。主要研究了外加磁场对c／c复合材料的Fe—Ni催化石墨化、电性能和力学性能的影响。结果表明，磁场作用下对含有铁磁性催化剂Fe—Ni的C／C复合材料的石墨化具有较好的改善作用；C／C复合材料的石墨化度越高其电阻率越低，并且电阻率在不同的磁场方向上呈现出了显著的差异性，平行于磁场方向上比垂直方向上的电阻率更低；但是，随着复合材料石墨化度的提高其抗压强度发生显著的降低。

THE CATALYTIC GRAPHITIZATION AND PERFORMANCES OF PAN/PHENOLIC RESIN-BASED C/C COMPOSITES BY Fe-Ni CATALYST IN AN EXTERNALLY MAGNETIC FIELD

Previous studies had shown that an externally applied magnetic field was found not only to promote the graphitization but also to improve the orientation of the hexagonal carbon layers. In this work, PAN/phenolic- based C/C composites（C/C composites）were oriented perpendicular or parallel to the direction of the external magnetic field. This study was concerned with the electrical resistivity of the C/C composites by the method of the present research. It was found that the resistivity of the C/C composites in the 45 mT magnetic field was smaller than that in the absence of a magnetic field. The higher the degree of graphitization of the composites, the smaller the resistivity. The composites treated on the parallel direction of magnetic field had a lower resistivity than the perpendicular magnetic field treated. However, it was found that an external magnetic field was unfavorable to the compression strength of the C/C composites.