Remarkable improvement in tribological behavior of plasma sprayed carbon nanotube and graphene nanoplatelates hybrid reinforced alumina nanocomposite coating

Addition of 0.5 wt% of graphene nanoplatelates (GNPs) and 1 wt% carbonnanotube (CNTs) in plasma sprayed Al2O3 coating showed the reduction of 93.25% in wear volume loss and 90.94% in wear rate. This could be attributed to the simultaneous effect of enhanced densification, presence of the transferred layer from the counterpart, strong interface between Al2O3, GNP and CNTs and toughening offered by the GNPs and CNTs. The lowest COF value of 0.27 was recorded on addition of 0.5 wt% of GNP in Al2O3 coating, which could be attributed to the graphitic lubrication on the worn track during the wear.