Microcrystal structure evolution of mesophase pitch-based carbon fibers with enhanced oxidation resistance and tensile strength induced by boron doping

Mesophase pitch-based carbon fibers (MPCFs) with various concentration of boron were fabricated through an easy and effective strategy by treating stabilized fibers with boron acid solution. The microstructural evolution of boron-doped MPCFs was characterized. It was found that boron doping promoted high degree of graphitization with the decrease of interlayer spacing and the growth of crystallite dimension due to catalytic graphitization of boron to carbon. Boron doping significantly improved 5 wt% burn-off temperature of MPCFs increasing by 344 degrees C, and the tensile strength of MPCFs was also enhanced by 19%. Both of the outstanding oxidation resistance and mechanical performance of MPCFs was obtained due to effect of boron. The results demonstrated boron doping was a feasible way to produce high-performance MPCFs.