Electrophoretic Deposition of Natural Hydroxyapatite

Abstract

Natural hydroxyapatite has been electrophoretically deposited on medical grade 316L stainless steel. Stable suspensions were prepared by mixing 40 g/L milled natural hydroxyapatite powder in isopropyl alcohol and stabilized by polyethylenimine as dispersing agent and binder. The stability of suspensions was investigated by measuring zeta potential. It was found here that the suspension which was stabilized with 4 g/L polyethylenimine revealed a high value of zeta potential and stability. Deposition was achieved on the cathode at constant voltages of 30, 60, and 90 V for 1 to 5 minutes. After deposition, the samples were dried at room temperature for 24 hours and deposition weight, roughness, and thickness of the coatings were measured. The surface morphology of the coated samples was studied by a scanning electron microscope. The results of the electrophoretic deposition process showed that the sample coated at 60 V and 3 minutes led to an adherent, continuous, and crack-free coating. The coating efficiency and thickness increased with increasing deposition time and yielded to saturation at the constant applied voltage. Also, the current density decreased and yielded to saturation at the constant applied voltage during electrophoretic deposition.