Self-assembly of graphene oxide and silane-modified silica for multiscale reinforcement of carbon graphite composites performance

Journal article, 2026

Carbon-graphite composites are widely used in fields such as aerospace and transportation. However, during high-temperature sintering, the pyrolysis and volatilization of the coal tar pitch binder can cause extensive cracking and porosity within the material, severely degrading its mechanical properties and limiting its further application. In this study, silane coupling agent-modified nano-silica was electrostatically self-assembled with graphene oxide to construct micro-nano multi-scale functional fillers, thereby fabricating carbon-graphite composites with excellent mechanical properties. The results indicate that GO is thermally reduced during sintering, while coal tar pitch is converted into pitch-derived carbon and the Si 2p signal is consistent with the formation of a Si–O–C-containing chemical environment. These structural and chemical changes, together with the reduced porosity and improved structural continuity, are associated with the enhanced densification and mechanical performance of the composites. The compressive and flexural strengths of the composite reached 121.83 and 41.04 MPa, respectively, corresponding to increases of 179.2% and 90.3% relative to those of the filler-free carbon-graphite composite. This study shows the effectiveness and application potential of graphene oxide and silica multi-scale fillers as reinforcing phases in carbon-graphite composites, providing novel insights for the design of high-performance carbon-based materials.