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Carbon fibers have promising applications in the efficient transmission of electric power with less resource consumption. Laser graphitization of the mesophase pitch-based carbon fiber (MPCF) was proposed to improve the electrical conductivity of the carbon fiber. The obtained MPCF showed a high conductivity of 7.04 × 105 S/m. The graphitization degree of carbon fiber increased and the interlayer spacing of its graphite crystal decreased on increasing the laser intensity. With a laser power of 360 W and an irradiation period of 25 s, corresponding to a temperature of 3001 °C, a high graphitization degree (R = 0.02) was obtained and the interlayer spacing was as small as 0.338 nm, close to that of pure graphitic carbon (0.335 nm). The enhanced electrical conductivity is attributed to the improved homogeneity of graphitization along the axial and radial directions, the ordered structural evolution, ordered stacking of the graphitic layer, and the promoted connectivity between the graphitic crystals in the carbon fiber. The energy consumption of the proposed method is estimated to be only 0.46% of that with the conventional Joule heating approach. This work suggests that laser-induced graphitization is a good alternative to prepare carbon fibers with high electrical conductivity and reduced energy consumption.

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Carbon/carbon–silicon carbide (C/C-SiC) composites have been widely reported in aerospace and military projects for their mechanical properties and electromagnetic shielding characteristics. However, high production costs, a complex process, and poor electrical conductivity have prohibited the large-scale application of these excellent EMI shielding materials. Herein, in situ growth of the SiC nanofibers (SiCnf) on carbonized phenolic resin with the reinforcement of graphite fibers is proposed for a strategy to overcome this challenge. The laser-irradiated carbon fibers (LCFs) were filled into the phenolic resin and hot-pressing was conducted; thereafter, the C/C-SiC composites were obtained by high-temperature carbothermal reduction of the LCF/phenolic resin and the industrial silicon power. Because of the conductive network of the LCF, the dense carbon matrix and the decoration of nanoporous SiCnf, the as-prepared SiCnf grown on the LCF/carbonized phenolic resin (LCF/PC-SiC) composite exhibited an EMI shielding effectiveness of 27.86 dB in the X-band at room temperature. This work proposed a new strategy to efficiently fabricate C/C-SiC composites for electromagnetic shielding.

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