▎ 摘　　要

We aim to understand the tribological properties of graphene nanoplatelets (GNPs) reinforced hydroxyapatite (HA) composite coating synthesized using plasma spray on Ti alloy substrate (Ti-6Al-4 V). A significant reduction of 83% in wear volume loss is observed on addition of 2 wt. % GNPs in HA as compared to bare HA coating, respectively. Similarly, coefficient of friction (COF) shows the relative reduction of 70% is HA-2 wt. % GNP coating. Post-wear analysis by Raman spectroscopy confirms the retention of GNPs with the enlarged defect over the worn surface. FE-SEM investigation of worn surface shows the strengthening mechanism such as GNP bridging, GNP pull-out which could be attributed to enhanced wear resistance of the coating. GNPs induced lubrication has been observed as the prime reason for lower COF of the worn surface.