Preparation of Polyamideimide/Polytetrafluoroethylene Composite Coatings and Its Tribological and Anti-Corrosion Properties

Polyamideimide/polytetrafluoroethylene (PAI/PTFE) multifunctional composite coatings with good tribological properties and excellent corrosion resistance were prepared. The CSM friction and wear tester was used to study the tribological performances of the coatings, and the P4000A electrochemical workstation was used to measure the electrochemical corrosion resistance of the PAI/PTFE composite coatings in 3.5% NaCl solution. The focus was on the influence of the solid mass ratio of PTFE to PAI on the tribological properties and corrosion resistance of the coatings. The results showed that the introduction of an appropriate amount of PTFE greatly enhanced the tribological properties and corrosion resistance of the PAI coatings. In particular, when the solid mass ratio of PTFE to PAI was 0.6, the coating exhibited the best tribological performances, as friction coefficient of 0.075 and wear rate of 3.72×10⁻⁶ mm³/(N·m). When the solid mass ratio of PTFE to PAI was 1, the low-frequency impedance value of the composite coatings immersed in 3.5% NaCl solution for 240 h was as high as 3.83×10⁹ Ω∙cm² showing excellent corrosion resistance. In addition, there were no blistering and rusting on the surface of the composite coatings exposed to salt spray test for 240 h. Such excellent tribological performances and corrosion resistance of PAI/PTFE composite coatings were attributed to the excellent lubricating properties of PTFE and the enhancement of the barrier properties of the coating to corrosive media.