Modification of electrophoretically deposited nano-hydroxyapatite coatings by wire brushing on Ti–6Al–4V substrates

In the present study, after successful synthesis of nano-HA powders by chemical precipitation method, wire-brushing (WB) treatment was effectively employed on Ti–6Al–4V substrates for the modification of electrophoretically deposited nano-hydroxyapatite coatings. The precipitated nano-HA particles were characterized by XRD, FT-IR, and DLS analyses. The morphology and particle size of synthesized nano-HA particles was observed by FE-SEM. The Ti–6Al–4V plates were initially wire brushed at different times and rotational speeds. Microhardness profile and AFM analysis of substrates were then studied. It was found that WB treatment at 16,000 rpm for 60 s leads to a maximum enhancement in the hardness and roughness of surface. Then, the electrophoretic deposition of nano-HA particles was carried out at constant voltage of 30 V and after 60 s. The results of adhesion test and potentiodynamic polarization measurements showed that WB treatment on Ti–6Al–4V substrates could efficiently increase the bonding strength between coating and substrate as well as corrosion resistance.