High densification and anti-corrosion of graphene-coated aluminum coating deposited on AZ31B magnesium by low-pressure cold spray

In this paper, graphene-coated Al powders prepared by in situ reduction method were directly used for cold spraying, obtaining a graphene-reinforced Al matrix composite coating with more compact structure and better performance. Cross-sectional analysis revealed that compared with the pure Al powders, the graphene-coated Al powders were more severely deformed, and the resulting coating was denser and its porosity was reduced by over 80%. The hardness of the graphene-coated Al coating was increased by 40%, and its brine immersion time was prolonged by nearly three times. However, the graphene increases the pitting sensitivity of the Al coating; so, the enhanced corrosion resistance of the graphene-coated Al coating is mainly attributed to the improvement of its structure densification.