Effect of suspension medium on the electrophoretic deposition of hydroxyapatite nanoparticles and properties of obtained coatings

The suspensions of hydroxyapatite (HA) nanoparticles were prepared in different alcohols. The zeta potential of HA nanoparticles was the highest in butanolic suspension (65.65 mV) due to the higher adsorption of RCH₂OH₂⁺ species via hydrogen bonding with surface P3OH group of HA. Electrophoretic deposition was performed at 20 and 60 V/cm for different times. Deposition rate was faster in low molecular weight alcohols due to the higher electrophoretic mobility of HA nanoparticles in them. The coating deposited from butanolic suspension had the highest adhesion strength and corrosion resistance in SBF solution at 37.5 °C. The surface of this coating was covered by apatite after immersion in SBF solution for 1 week.