Corrosion Behaviors of Zn, Si, and Mn-Doped Hydroxyapatite Coatings Formed on the Ti-6Al-4V Alloy by Plasma Electrolytic Oxidation.

Ti alloy for implant materials is not good biocompatibility between metal implants and natural bone without surface modification. In order to improve the bone attachment ability, implant surface modification is required, and corrosion resistance is also important when a surface modified implant is inserted into the body. In this study, corrosion behaviors of anodic oxide film formed on Ti-6Al-4V alloy with concentration of Mn and Zn ions were studied using various experimental techniques. Ti-6Al-4V ELI disk were used as the substrate for PEO treatment. The sample was used a anodic electrode and PEO treatment was carried out by varying the content of each of the electrolytic solutions containing Zn, Mn, Si, Ca and P, using a Pt bar as a cathodic electrode. Pulsed DC power was used at 280 V for 3 min. For the corrosion behaviors of the specimens, the potentiodynamic polarization and AC impedance test were carried out in 0.9% NaCl solution. From the result of experiments, as Zn ion content increases, the number of pores and the pore size increase. As the Mn ion increases, the number of pores decreases, while the pore size increases. As the ions of Mn increase, the corrosion potential decreases. As Zn ion content increased, the polarization resistance increased.