Orientation of carbon fiber in magnesium-doped hydroxyapatite and its effect on mechanical and tribological properties of carbon fiber reinforced composites

Carbon fiber (CF) reinforced magnesium-doped hydroxyapatite (Mg-HA) composites have been shown possess excellent mechanical performance and tailored biological properties. In order to further explore the effect of the orientation for short CF reinforced Mg-HA composites for mechanical and tribological properties. Micro-sized CF was oriented in Mg-HA by a self-developed mold and highly oriented CF reinforced magnesium doped hydroxyapatite (OCF/Mg-HA) composites were prepared by spark plasma sintering (SPS). The morphology, structure, wettability, mechanical properties and tribological properties of the composites were investigated. The results show that the average contact angle of oriented CF/Mg-HA composites was 67.65° and had good hydrophilicity. Compressive strength of OCF/Mg-HA in the direction parallel to the fiber was 129.8 MPa, which met the requirements of mechanical properties of human cortical bone. In addition, the wear resistance of OCF/Mg-HA ceramics was significantly improved by the addition of CF. The average friction coefficient of OCF/Mg-HA ceramics in the direction parallel to the fiber was 0.157. OCF/Mg-HA ceramics exhibited excellent tribological properties and mechanical properties which were close to that of human load-bearing bone due to the oriented arrangement of CF. This laid a foundation for the clinical application of OCF/Mg-HA ceramics in the repair of bone defects at load-bearing sites.