Corrosion behaviour of hydroxyapatite (HAP) coated AISI 316Ti austenitic biomaterial

Abstract

Abstract HAP bioactive coatings are widely applied to improve the bone response in orthopedic and dental stainless steels implants. Mechanical properties of the metallic implant are preserved and moreover, HAP improves the corrosion resistance. This article deals with the corrosion resistance of AISI 316Ti austenitic biomaterial with electrochemically deposited HAP coating. Corrosion behaviour is evaluated on the bases of two independent methods-the electrochemical potentiodynamic polarization test and exposure immersion tests, both carried out in physiological solution (0.9 % NaCl) at the temperature 37 ± 0.5 °C. The microstructure and chemical composition of HAP coating is evaluated by SEM and EDX analysis. According to the results of the potentiodynamic test, the HAP coated biomaterial shows the considerably higher corrosion resistance compared to that without the HAP coating. However, the corrosion losses and SEM analysis after the exposure test revealed severe disruption of the HAP coating and the stainless steel substrate started to corrode.