Plasma-Sprayed Alumina Coating Reinforced with Carbon Nanotubes and Graphene Nanoplatelets: Wear Performance in Adverse Environment

The unique mechanical, chemical, and tribological properties of members of graphene family make them a consummate reinforcement candidate for improving the wear resistance properties of matrices. The present work conveys the tribological behavior of the plasma-sprayed alumina (Al₂O₃) coatings in various conditions, such as at high temperature as well as in marine condition by reinforcing carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) into it. Synergistic reinforcement of CNTs and GNPs decreased the coefficient of friction (CoF) by 45% at room temperature and by ~ 50% at high temperature as well as in simulated seawater. Additionally, weight loss after wear almost decreased by 6–7 folds for ACG coating. The key reasons attributed for these improvements are: (a) formation of stable film during the wear; (b) lubricative properties of the reinforcement; and (c) higher fracture toughness of ACG coating as compared to others. Elemental mapping of the worn track of the ACG tracks showed a uniform distribution of elements over them which assisted in improving the wear performance of ACG in all the adverse ambiences.