Corrosion and Tribocorrosion Resistance of Polyamide‐Imide/Polytetrafluoroethylene/Flake Aluminum Composite Coatings in Different Corrosive Media

ABSTRACT

This study prepared polyamide‐imide/polytetrafluoroethylene/flake aluminum (PAI/PTFE/Al) composite coatings and investigated their corrosion and tribocorrosion resistance in artificial seawater, 0.01 mol/L NaOH, and 0.01 mol/L HCl media. The results showed that the medium significantly influenced coating performance. The coating demonstrated excellent corrosion resistance after 720 h of immersion in both HCl medium and artificial seawater, maintaining low‐frequency impedance modulus (| Z | _0.01Hz ) values of 5 × 10 ¹⁰  Ω·cm ² and 2.53 × 10 ¹⁰  Ω·cm ² , respectively. In contrast, it exhibited the weakest corrosion resistance in NaOH medium, with | Z | _0.01Hz decreasing to 4.60 × 10 ⁵  Ω·cm ² . During tribocorrosion testing, the coating exhibited the highest open circuit potential (OCP) in HCl medium, and an Al(OH) ₃ ‐dominated protective film formed on the worn surface, yielding the lowest friction coefficient (0.052) and wear rate (5.30 × 10 ⁻⁶  mm ³  N ⁻¹  m ⁻¹ ). However, the coating showed the lowest OCP and the most severe tribocorrosion behavior in NaOH medium, as the flake aluminum dissolved into soluble AlO ₂ ⁻ , thereby preventing the formation of an effective protective layer. The variation in coating performance across different media originated from the distinct corrosion products formed by aluminum fillers and their role in regulating the tribocorrosion coupling process. The findings of this study provided a theoretical basis for designing high‐performance protective coatings tailored to specific tribocorrosion environments.