Nano hydroxyapatite (HA)/polypyrrole (PPy)/Ag composite coatings were prepared using pulse electrochemical deposition on biomedical titanium surfaces.The effects of Py concentration

Ag+ concentration

and salt concentration on the morphology and composition of the composite coatings were investigated.This study discussed the formation of spherical HA-NPs and Ag-NPs in the PPy polymerization process

and the biological activity

physical stability and anti-bacterial properties of the composite coating.The results showed that the concentration of Py in the electrolyte could affect the morphology of the coating;the Py concentration of 0.03 mol/L was found to be beneficial to the deposition of the composite coating.The concentration of Ag+ in the electrolyte affected the morphology and crystallization of the coating

and the optimal concentration of Ag+ in the electrolyte was determined to be 0.3 mmol/L.The morphology and crystallization of the coating were influenced by Ca2+ concentration in the electrolyte

higher concentrations led to particle size increase and Ca2+ concentration of 5.0 mmol/L was determined to be the most suitable for the electrolyte.The composite coating could induce the formation of HA

in particular

the (002) crystal plane exhibited preferred growth and demonstrated good biological activity.The addition of PPy greatly reduced the release rate of Ca2+ and Ag+ and improved the physiological stability of the composite coating.Antibacterial tests showed the composite coating demonstrated good antimicrobial properties.