Exploration of aviation bearings protection: Highly corrosion-resistant and wear-resistant biomimetic composite coatings inspired by mussels

Aircraft engines are subject to salt spray erosion in marine environments, and the protection of bearings faces a dual challenge of anti-wear and anti-corrosion. This paper was inspired by mussels and prepared a polydopamine nano-SiO2 modified stearic acid composite organic coating on the surface of bearing steel by in-situ polymerization. The results indicate that the composite coating has excellent corrosion resistance in seawater, reducing the current density from 3.87 x 10-5 A/cm2 to 2.13 x 10- 7 A/cm2. The biomimetic microstructure effectively enhances the hydrophobicity of the coating, increasing the contact angle from 76.84 degrees to 145.1 degrees. The composite coating exhibits plastic deformation under high stress conditions of 17.55 GPa, with a stable friction coefficient between 0.11 and 0.12. According to first principles calculations, polydopamine as an intermediate layer increases the minimum interfacial energy from 14.11 kJ/mol to 23.96 kJ/mol. This polymer dopamine nano-SiO2 modified stearic acid composite organic coating is expected to be used in moving parts such as aircraft bearings to reduce corrosion and wear, and extend service life.