Preparation, corrosion and tribological properties evolution of self-lubricating Al2O3-TiO2 coatings with superior anti-corrosion

Reliable and long-lasting self-lubricating, wear-resistant, and corrosion-resistant ceramic-based coatings are vital for combating coupling damage in marine environments. However, the lack of understanding of marine protective coatings' damage mechanisms has hindered the development of design theories. Therefore, the development of integrated coating preparation techniques and corrosion-wear evolution research are urgently needed. This study introduces carnauba wax into thermally sprayed ceramic coatings via vacuum-hot impregnation, creating a composite coating that exhibits corrosion resistance, wear resistance, and lubrication. Analyzing the electrochemical and tribological performance tests of the composite coatings under various corrosion cycles aims to investigate the protective effect of the coatings and the corrosion/friction evolution patterns. The results indicate that carnauba wax seals micro-nano defects of the coating. Simultaneously, carnauba wax within the coating defects imparts hydrophobic properties (>112°), decreasing seawater interaction with the coating surface. Over a 70-day corrosion testing period, the polarization resistance ( R p ) of the coating reached 2.42 × 10 7  Ω·cm 2 , indicating excellent corrosion resistance. A well-covered lubricating film composed of Al 2 O 3 , ZrO 2 , and carnauba wax was formed in the wear area, with carnauba wax providing a low friction coefficient (<0.2), while nano Al 2 O 3 and ZrO 2 enhance the load-bearing capacity of the lubricating film. Throughout the full corrosion cycle, the coating demonstrates stable and excellent lubricating wear resistance; the wear rate is only 8.58 × 10 −7  mm 3 ∙N −1 ∙m −1 . This research offers new protective strategies for components in marine environments while exploring long-term corrosion-wear evolution of coatings.