Synergistic mechanism of MoS2 and PTFE in reinforcing epoxy-based composite coatings

To address the urgent demand for enhanced durability and tribological performance of epoxy (EP) coatings in transmission components such as sliding bearings and gears, this study proposes a novel “soft–hard” synergistic filler strategy by incorporating MoS₂ and PTFE into an EP matrix. Although EP possess strong adhesion and chemical resistance, their inherent brittleness and poor wear resistance severely restrict their application under high mechanical loads. While various fillers have been investigated to improve EP's tribological properties, the combination of soft PTFE with hard MoS₂ offers a promising yet underexplored approach to simultaneously enhance toughness, reduce friction, and improve wear resistance. In this work, the effects of MoS₂ and PTFE on the mechanical and tribological properties of the EP matrix were systematically investigated using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and their synergistic mechanism was elucidated. The results indicated that MoS₂ effectively enhanced the elastic modulus and hardness of the coating, while PTFE diminished these properties. When co-incorporated, the MoS₂/PTFE/EP coating exhibited the lowest coefficient of friction and wear rate, which were significantly reduced by 74.2 % and 97.3 %, respectively, compared to those of the pure EP coating. This remarkable performance enhancement was primarily attributed to the synergistic effects of MoS₂ and PTFE in three aspects: complementary mechanical properties, enhanced interfacial stability, and the formation of a robust, continuous composite transfer film. This study provides a key strategy and theoretical foundation for the filler design of high-performance, long-service-life EP-based self-lubricating coatings.