Review of epoxy nano-filled hybrid nanocomposite coatings for tribological applications

Epoxy resins, known for their chemical stability, electrical insulation, and bonding properties, are widely used in mechanical friction applications. However, their brittleness and low abrasion resistance limit their tribological performance. To address these challenges, researchers have focused on enhancing the tribological properties of epoxy coatings by incorporating various nanofillers. This review highlights the significant impact of nanofillers, such as graphene oxide (GO), molybdenum disulfide (MoS₂), and polytetrafluoroethylene (PTFE), on the friction, wear resistance, and thermal stability of epoxy nanocomposite coatings. For instance, the inclusion of MoS₂ in epoxy resulted in up to a 90 % reduction in the coefficient of friction, while rGO and PTFE composites exhibited an 88 % improvement in wear rate and an 88 % reduction in friction. Additionally, hybrid nanofillers, such as MoS₂-graphene combinations, demonstrated remarkable synergy, reducing friction by 99 % compared to pure epoxy coatings. The practical implications of these findings are profound, offering enhanced durability, reduced energy loss, and improved performance in high-stress mechanical applications such as automotive, aerospace, and industrial machinery. These improvements also have the potential to contribute to increased fuel efficiency and reduced environmental impact by lowering CO₂ emissions. This review emphasizes the trends and challenges in scaling up these nanocomposite systems, highlighting future research directions for optimizing nanofiller dispersion and addressing mechanical degradation under harsh conditions.