Determination of the optimum amount of iodine in electrophoretic deposition of hydroxyapatite (HA) nanoparticles

In this research, the hydroxyapatite (HA) nanoparticles were deposited on sandblasted titanium by electrophoretic deposition method. In this case, isopropanol-acetone suspension with 50/50 ratio was used by using iodine as a dispersant. The suspensions were prepared with various concentrations of iodine (0, 0.2, 0.4, 0.6, and 0.8 g/L). Furthermore, the pH of suspension, the electrical conductivity of the suspension mediums, and the zeta potential, mobility, and particle size distribution of HA nanoparticles were measured in suspensions. In the next step, the optimum content of iodine was determined to provide a sustainable suspension. Then, HA coating was deposited on sandblasted titanium surface. The current density during electrophoretic deposition (EPD) and deposition rate in different voltages were investigated. The microstructure and morphology of the sediments were examined by using FE-SEM and AFM. Finally, the structure and phase composition of the coatings were analyzed by using XRD before and after sintering. Furthermore, the adhesion strength of the coating to the substrate was measured. The results show that 0.6-g/L iodine prepared a stable suspension and the effect of current density and potential on the deposition weight is determined. In additional, the results show a finer and narrower particle size distribution can be observed. Also, adhesion strength of the coatings to the sandblasted titanium surface is about 11 MPa.