Corrosion Resistance of Zinc-Doped Hydroxyapatite Coating on Titanium Substrate using Plasma Electrolytic Oxidation for Biomedical Applications

This paper presents a method for depositing zinc-doped hydroxyapatite (HA) (Zn²⁺) on titanium (Ti/HA-Zn) using the plasma electrolytic oxidation (PEO) method in an electrolyte solution. The influence of the electrolyte composition on microstructural properties such as phase composition, and corrosion resistance of the Ti/HA-Zn coating is investigated. The PEO process is carried out in a solution containing calcium ions and phosphorus ions to form a hydroxyapatite layer on the surface of the titanium substrate. Additionally, the effect of zinc doping concentration in the hydroxyapatite layer on electrochemical properties compared to the undoped hydroxyapatite coating is studied. Surface morphology and phase are examined using scanning electron microscopy and x-ray Diffraction. Corrosion resistance properties of the samples are analyzed in a simulated body fluid solution using electrochemical impedance spectroscopy and polarization curve measurements (I–E).