Research on tribological behavior of graphene with in-situ MgO nanoparticles reinforced AZ91 alloy composite

Magnesium-coated graphene (GNPs) was successfully prepared by a novel organic chemical reduction method with significantly improved wettability and dispersion. The GNPs were uniformly distributed in the matrix, while a finer and more dispersed strengthening phase β-Mg17Al12 was precipitated around it. Moreover, MgO nanoparticles were formed by in-situ reaction on the surface of GNPs, forming nano-scale contact and tight interfacial bonding with the substrate, thereby significantly improving the wear resistance of the composites. The wear mechanism has also changed from severe delamination and abrasive wear to mixed wear of slight delamination, adhesion, and oxidation. The increase in wear resistance is attributed to the combined effect of the lubrication and load transfer of GNPs, the enhanced effect of fine precipitates on the mechanical properties of the matrix, and the synergistic effect of in situ generated MgO nanoparticles against deformation.