Enhancing tribological performance of micro-arc oxidation coatings on Mg-Li alloy with h-BN incorporation

Microarc oxidation (MAO) coatings incorporating hexagonal boron nitride (h-BN) nanoparticles were synthesized on Mg-Li alloys. The effects of h-BN nanoparticle concentration on the structure, phase composition, and tribological properties of the MAO coatings were systematically investigated. The results indicate that the addition of h-BN nanoparticles induces the formation of protrusions on the coating surface, varied in size and distribution with the concentration of h-BN particles. The protrusions are advantageous for enhancing the wear resistance of the coating, owing to the effective reduction of the contact area and the lubricating impact of the released h-BN particles during wear. The thickness and hardness of the coating contained h-BN particles are significantly elevated. At an optimal h-BN concentration of 7 g/L, the composite coating exhibits the lowest average coefficient of friction (COF = 0.59) and the minimum wear rate (W = 2.6 × 10 −6 mm 3 /N·m), thereby demonstrating superior tribological performance.