Preparation and characterization of hydroxyapatite coating on Ti6Al4V cylinders by combination of alkali-heat treatments and biomimetic method

ABSTRACT

Biomimetic method was used to apply hydroxyapatite [HA] coating onto Ti6Al4V cylinders. This process is a physicochemical method in which a substrate is soaked in a solution simulating the physiological conditions, for a period of time enough to form a desirable layer of the calcium phosphate on the substrate. In the present study, specimens were soaked in 5, 10 M solutions of NaOH at temperatures of 60 or 80°C for 24 and 72 h. Surface of samples were characterized using scanning electron microscopy [SEM] and thin film X-ray diffraction [TF-XRD]. The optimum condition was found to be 72 h of soaking in 5 M NaOH at 80§C. Specimens treated under these optimum conditions were subsequently heat-treated at 500, 600, and 700°C for 1h in order to consolidate the sodium titanate hydrogel layer. Under the heat treatment condition of 600°C for 1h and subsequent soaking in simulated body fluid [SBF], apatite formed within 3 days. It was observed that, apatite formation increased significantly, which is an indication of the materials ability for use as a load bearing implant