Development of the surface properties of alloys that produced for biomedical applications

Among metallic biomaterials Titanium (Ti) and its alloys have been commonly used in medical application for many years. Beta-type Ti alloys are preferred due to their low elasticity modulus, good corrosion resistance and high biocompatibility compared to other alloy types. In recent years, researches on the development of Ti alloys have been focused on alloys produced by transition metals such as Zirconium (Zr), Niobium (Nb) and Molybdenum (Mo) because of their superior mechanical properties, biocompatibility, high corrosion resistance. The purpose of this study is to produce Niobium and Molybdenum added binary and ternary Ti alloys for use in biomedical applications and to improve their surface properties. Therefore, 15 and 42 weight percent Niobium containing two binary alloys and 15 weight percent Niobium and 15 weight percent Molybdenum containing one ternary alloy were produced by using a vacuum arc melter (VAM). In order to ensure integration with bone during use, porous and stable oxide layers were formed by micro arc oxidation (MAO) on the alloy surfaces. With the solution used in the MAO method it was provided that the integration of the bioactive Magnesium ions which has been also in bone structure into oxide layer. Elastic modulus of the produced alloys was measured by the dynamic ultra microhardness (DUH) device. Characterization of the alloys and oxide layers developed on the surface of alloys were done by X-ray diffractometer (XRD) and scanning electron microscopy (SEM). According to the results, the elastic modulus values of the binary and ternary alloys produced were lower than the Ti6Al4V alloy used commercially. On all alloy surfaces, Calcium-Magnesium phosphate-containing Ti oxide layers were developed by MAO method. It was concluded that hydroxyapatite (HAP) structure developed rapidly on the oxide layer formed on the ternary alloy surface after different time retention experiments in body fluid-like solution (SBF). Keywords: Titanium alloys, vacum arc melting, micro arc oxidation