Interfacial Stress Regulation by Carbon Fiber–Graphene Oxide in Phosphate Bonded Coatings: A Mechanistic Insight Into High‐Temperature Tribological Performance

In this work, graphene oxide‐modified carbon fibers (CF‐GO) were fabricated via layer‐by‐layer self‐assembly and incorporated into a phosphate‐bonded coating to evaluate their role in high‐temperature tribological performance. The underlying mechanism by which CF‐GO enhances wear resistance was elucidated. The results demonstrate that CF‐GO significantly improves the coating's tribological properties. Compared to the coating without CF‐GO, the coating with 15% CF‐GO exhibits reductions in the friction coefficient by 55%, 37%, and 42%, and in the wear rate by 87%, 82%, and 76% at 100, 300, and 500 °C, respectively. Both the friction coefficient and wear rate increase with temperature at a given CF‐GO content. Simulations reveal that temperature and stress act synergistically under coupled thermo‑mechanical loading, accelerating damage and wear rate with increasing temperature. Furthermore, the strengthened interfacial bonding introduced by CF‑GO increases the stress carried by both the fiber and the interface. The enhanced performance on the tribological behavior is attributed to solid lubrication from the exposed CF‐GO, crack‑inhibiting effects, and improved load‑bearing capacity enabled by strong interfacial bonding. However, as temperature rises, increased interfacial stress and thermal decomposition degrade the interfacial bonding, weakening stress transfer and thereby reducing the wear resistance of the coating.