Ternary hydroxyapatite/chitosan/graphene oxide composite coating on AZ91D magnesium alloy by electrophoretic deposition

In this work, ternary HA/chitosan/graphene oxide (GO) coating was applied via electrophoretic deposition on AZ91D magnesium alloy as bone implants, successfully. Subsequently, phase composition, surface morphology, hardness, corrosion behavior, bioactivity and antibacterial of the composite coatings were studied. Hardness and Young's modulus of the composite coatings increased from 40 +/- 1.5 MPa and 3.1 +/- 0.42 GPa to 60 +/- 3.12 MPa and 8 +/- 0.53 GPa for composite coatings with 0 and 2 wt% GO, respectively. The results of the SBF solution soaking of the composites after 24 days, indicated the improvement of HA growth due to the increasing of the GO addition in composite coating. New HA grains with leaf-like morphology grew uniformly at higher amounts of GO (1 and 2 %wt) in a perfectly balanced composition. Rate of the substrate corrosion significantly decreased from 4.3 to 0.2 (mpy), when the amount of GO increased from 0 to 2 wt% due to reduction of the surface cracks at the presence of the GO reinforcement. Also, there was no Escherichia coli and Staphylococcus aureus bacteria growth in broth medium after 24 h and OD600 results at 24 h post inoculation for the 2%wt GO addition in coating.