Ultrasonic-assisted MoS2/GO/TiO2 ceramic coatings: Enhancing anti-friction performance through dual-interface optimization.

Abstract

Ceramic coatings containing two-dimensional materials (2D materials) provide effective protection for light alloys during wear, significantly improving their anti-friction performance. MoS₂ has proven highly effective in enhancing the anti-friction performance of ceramic coatings, particularly when synthesized via plasma electrolytic oxidation (PEO). However, dislocation pinning due to the incoherent interfaces in MoS₂/TiO₂ coatings tends to cause localized stress concentrations and brittle fracture, requiring effectively improve nanomechanical properties by optimizing interface design. To address these issues, this study used ultrasonic-assisted PEO to disperse graphene oxide (GO), which provided more possibility for in-situ synthesis MoS₂, ultimately resulting in MoS₂ with modified interlayer spacing. The change in interlayer spacing induced dislocation evolution at incoherent interface, leading to dual interface formation. At MoS₂ (0.534 nm)/TiO₂ interface: dislocation dipoles evolve to create considerable distortion, facilitating releasing shear stresses and inhibiting crack propagations. This process is followed by dislocation annihilation, keeping to stable interfacial bonding. Additionally, the others form strong dislocation pinning to obstruct dislocation slip and enhancing deformation resistance at MoS₂ (0.227 nm)/TiO₂ interface. The combined effects of dual interfacial enhancements resulted in a 90.0 % reduction in friction coefficients of the MoS₂/GO/TiO₂ coating compared to the traditional ceramic coating. This facile technique provides a new strategy to fabricate self-lubricating ceramic coatings on light alloys, while the introduction of ultrasound during PEO offers valuable guidance for applying ultrasound in the synthesis of 2D materials.