Synchronously constructing networked Si3N4 nanowires and interconnected graphene inside carbon fiber composites for enhancing mechanical, friction and anti-ablation properties

Carbon fiber (Cf) reinforced pyrolytic carbon (PyC) composites simultaneously possessing robust mechan-ical strength, excellent friction performances and outstanding anti-ablation properties are demanded for advanced aerospace applications. Efficient architecture design and optimization of composites are promi-nent yet remain high challenging for realizing the above requirements. Herein, binary reinforcements of networked silicon nitride nanowires (Si3N4nws) and interconnected graphene (GE) have been successfully constructed into Cf/PyC by precursor impregnation-pyrolysis and chemical vapor deposition. Notably, net-worked Si3N4nws are uniformly distributed among the carbon fibers, while interconnected GE is firmly rooted on the surface of both networked Si3N4nws and carbon fibers. In the networked Si3N4nws and in-terconnected GE reinforced Cf/PyC, networked Si3N4nws significantly boost the cohesion strength of PyC, while GE markedly improves the interface bonding of both Si3N4nws/PyC and fiber/PyC. Benefiting from the synergistic reinforcement effect of networked Si3N4nws and interconnected GE, the Cf/PyC have a prominent enhancement in mechanical (shear and compressive strengths increased by 119.9% and 52.84%, respectively) and friction (friction coefficient and wear rate reduced by 25.40% and 60.10%, respectively) as well as anti-ablation (mass ablation rate and linear ablation rate decreased by 71.25% and 63.01%, respec-tively). This present strategy for networked Si3N4nws and interconnected GE reinforced Cf/PyC provides a dominant route to produce mechanically robust, frictionally resisting and ablatively resistant materials for use in advanced aerospace applications.(c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.