Effect of surface modifications by abrasive water jet machining and electrophoretic deposition on tribological characterisation of Ti6Al4V alloy

Abrasive water jet (AWJ) milling has speedily developed in popularity due to its adaptability and fast production of blind features like channels, pockets etc. But the surface property of AWJ-milled samples was found to be poor, restricting the process of being commercially used widely. In this work, a two-step methodology has been tried to modify the surface properties of Ti6Al4V substrate, which includes fast fabrication of miniaturised channel using AWJ technique followed by electrophoretic deposition (EPD) of hydroxyapatite-carbon nanotube (HAp-CNT) coating. The fretting wear test divulges the enhanced wear resistance of synergistically textured Ti6Al4V substrate with EPD HAp-CNT, due to its lower coefficient of friction (0.22 +/- 0.0) and wear depth (- 18.1636 mu m) when compared with that of textured Ti6Al4V (0.27 +/- 0.005 and - 18.8221 mu m, respectively). The coefficient of friction and wear depth were observed to be highest for bare Ti6Al4V sample (0.41 +/- 0.007 and - 27.4985 mu m, respectively). The observed increment in wear resistance is due to the textured channels trapping the wear debris and a decrease in the real contact area due to the coating of HAp-CNT. Thus, fabrication of micro-channels by AWJ combined with HAp-CNT coating may provide potential self-lubrication and enhance damage tolerance of Ti6Al4V alloy for biomedical and manufacturing applications.