Deposition of Hydroxyapatite Coating on Ti-6Al-4V Substrate by Electrochemical Method at Ambient Temperature

Hydroxyapatite coating on Ti substrate is being used more frequently as a bone replacement material. Several methods such as plasma spray, sol-gel, ion beam assisted deposition and electrochemical methods can be used for applying hydroxyapatite on Ti substrate. Controlling microstructure of the coating is one of the advantages of electrochemical methods. In this work hydroxyapatite coatings were applied by electrochemical method on Ti-6Al-4V substrate under a coating voltage of 4V and amperage of 4mAcm-2. The coating bath contained Ca(NO3)2. 4H2O and NH4H2PO4 at a pH of 4.1. The samples were heat treated at 550oC for 4hr. The microstructure and the composition of the coatings were investigated by scanning electron microscope (SEM) and X-Ray diffraction (XRD) methods before and after the heat treatment. The results showed a more compact coating with an increased amount of hydroxyapatite after the heat treatment.