Synchronously promoted mechanical and biotribological properties of carbon fiber composites by constructing Si₃N₄ nanowires@pyrolytic carbon intertwined network

Constructing strong interaction architecture is the key to achieve high performance of composite materials, where the combination of high mechanical strength and excellent biotribological properties are required. Herein, Si₃N₄ nanowires@pyrolytic carbon core-shell structure (SNs@PyC) are designed and constructed into carbon fiber-carbon-hydroxyapatite composites (CHC) for improving the mechanical and biotribological performances. SNs@PyC enhanced CHC (SNs@PyC-CHC) are fabricated by a combined method composed of precursor impregnation-pyrolysis, chemical vapor deposition, pulse electrochemical deposition and isothermal chemical vapor infiltration. SNs@PyC are distributed inside CHC uniformly with intertwined network structure. SNs@PyC induces the uniform deposition of hydroxyapatite matrix, favors the infiltration of the carbon matrix, enhances the interface between carbon matrix and Si₃N₄ nanowires, and promotes the cohesion strength of the carbon matrix. Compared with CHC, the flexural strength, compressive strength and shear strength of SNs@PyC-CHC are increased by 63%, 47% and 300%, respectively. In addition, the friction coefficient and wear rate of SNs@PyC-CHC are decreased by 55% and 84%, respectively. SNs@PyC-CHC may have a promising application in biomedical.