Catalytic graphitization of polyacrylonitrile (PAN)-based carbon fibers with Fe-Cr2O3 composite coating

The process of electrodepositing Fe-Cr2O3 composite coating on polyacrylonitrile (PAN)-based carbon fibers and its catalytic graphitization were studied. Carbon fibers with and without electrodeposited Fe-Cr2O3 composite coating were heat treated at different temperatures and the structural changes were characterized by XRD, Raman spectroscopy and SEM. The results indicate that Fe-Cr2O3 composite coating exhibits a significant catalytic effect on graphitization of carbon fibers at low temperatures. When the Fe-Cr2O3-coated carbon fibers were heat treated at 1 300 °C, the interlayer spacing (d002) and ratio of relative peak area (AD/AG) reach 3.364 Å and 0.34, respectively. Whereas, the extent of graphitization of pristine carbon fibers is comparatively low even after heat treatment at 2 800 °C and the values of d002 and AD/AG are 3.414 Å and 0.68, respectively. The extent of graphitization of carbon fibers increases not only with the increase of the catalyst gross but also the Cr2O3 content in Fe-Cr2O3 coating. The catalytic effect of Fe-Cr2O3 composite coating accords with the dissolution-precipitation mechanism.