Long-term anti-friction gradient coating on titanium alloys by plasma electrolytic oxidation with efficient strain transfer

A MoS2 concentration gradient coating of an osteoarticular-like structure with efficient strain transfer efficiency was prepared on titanium alloy via multiple plasma electrolytic oxidation. This structure facilitates efficient strain transfer by dissipating compressive and shear strains via dislocation annihilation and MoS2 interlayer sliding, thereby preserving a strain gradient. Leveraging this mechanism, the coefficient of friction was reduced by 50.2% compared to graphene coatings, while the frictional stabilization time was extended by 160% about Single MoS2/TiO2. This study elucidates the dislocation behavior and the mechanisms of strain transfer during friction within this structure.