An Interfacial Strategy Incorporating Multiscaled Calcium Hydrogen Phosphate Dihydrate Nanosheets/Microsheets Into Carbon Fiber Composites

Carbon fiber composites are considered ideal candidates for orthopedic implants due to their elastic modulus being similar to that of human bone, but the interfacial bonding between carbon fibers and matrix is still a challenge. In this work, the multiscaled calcium phosphate dihydrate nanosheets/microsheets (CHPDnm) are introduced on the surface of carbon fibers by a one-step pulsed electrodeposition method (PED), which significantly improves the mechanical and biofriction properties of carbon fiber composites. CHPD nanosheets grow in situ on the surface of carbon fibers, which improves the fiber/matrix interface bonding. CHPD microsheets extend into the matrix and enhance the cohesion of the matrix. The mechanical and biofriction properties of carbon fiber composites are improved by the synergistic effect of CHPD nanosheets and microsheets. Compared to the pristine carbon fiber composites, the flexural and compressive strength of CHPDnm-reinforced carbon fiber epoxy resin/phenolic resin/pyrolytic carbon (CHPDnm-CE, CHPDnm-CP, and CHPDnm-CC) are enhanced by 18.1%, 118.31%, 218.0% and 53.3%, 32.33%, 41.3%, respectively. In addition, CHPDnm-CE, CHPDnm-CP, and CHPDnm-CC showed a reduction of 80.5%, 50.0%, and 21.6% in wear rate. This work provides a practical strategy for the surface modification of carbon fibers while broadening their application as orthopedic implants.