Enhanced tribological and anti-corrosion of epoxy/PTFE composite coating via KH-550 silane coupling agent modification

Polytetrafluoroethylene (PTFE) is an attractive filler for organic coatings due to its low friction and chemical inertness, yet its poor interfacial compatibility with the matrix severely limits the coating’s protective performance. In this work, a silane coupling agent (KH-550) was employed to modify PTFE particles via hydrolytic condensation, and the resulting M‐PTFE filler was incorporated into an epoxy resin to fabricate a composite coating. The successful formation of a polysiloxane network on the PTFE surface was confirmed by SEM, FTIR and XPS. Compared with the unmodified PTFE coating, the EP/PTFE coating exhibited a higher water contact angle (95.1 °) and microhardness (41.4 HV). Tribological tests showed that the EP/M‐PTFE coating achieved a low friction coefficient and a wear rate of only 6.2×10-6 mm³/(N·m), which is approximately 1.3% of that of the EP coating. Electrochemical measurements revealed that after 480 h immersion in 3.5 wt.% NaCl solution, the EP/M‐PTFE coating maintained a low corrosion current density (10-10 A/cm2) and a high |Z|0.1Hz (>108 Ω·cm2). Moreover, under sliding in a corrosive environment, the coating simultaneously preserved a stable open‐circuit potential and a low friction coefficient, demonstrating excellent tribo-corrosion resistance. The remarkable performance is attributed to the strong interfacial bonding between M‐PTFE and the epoxy matrix, which prevents filler pull‐out, suppresses defect formation, and maintains the structural integrity of the coating. This work provides an effective strategy for designing high‐performance protective coatings that combine outstanding wear resistance and long‐term corrosion protection.