Self-lubricating micro-arc oxidized polytetrafluoroethylene composite coating on rivet steel for improve corrosion/wear resistance

To improve contact corrosion between auto parts of magnesium alloy and steel rivets during cold connection, a polytetrafluoroethylene (PTFE)-micro-arc oxidation (MAO) composite coating (PTFE-MAO) was prepared on 10B21 steel in the electrolyte consisting of aluminate and phosphate in this work. PTFE carrying anionic surfactant drills into the discharge channel due to the electrostatic adsorption of anions and cations, which plays a role in plugging holes. It shows that PTFE concentration has a significant effect on phase composition, surface microstructure morphology, and corrosion property of MAO coatings. In particular, for the PTFE concentration of 6 g/L, it greatly improves the coating's corrosion resistant , wear resistance, and hydrophobicity . In addition, glycerol (C 3 H 8 O 3 ) with 2 mg/L was added to the electrolyte containing PTFE to obtain a composite coating, the corrosion resistance of which is significantly improved, and the decrease in salt spray corrosion rate is doubled compared to the MAO coating. This approach provides a reference for preparing multifunctional anticorrosion coatings on steel substrates.