Corrosion resistance studies of copper and magnesium-doped fluorohydroxyapatite coatings on titanium biomaterial

This study discusses the contribution of Cu2+ and Mg2+, two biologically important ions substituted into the structure of fluorohydroxyapatite. FHA, a partial substitution of fluorine ion in HA has received a great attention because it improves the corrosion resistance of orthopedic implants. Copper, Magnesium and copper-Magnesium doped fluorohydroxyapatite (FHA) coatings were electrochemical deposited on titanium (Ti) using a cyclic voltammetry technique. The coatings properties were identified by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The corrosion behavior of coated and uncoated samples, immersed for 7 days in aerated simulated body fluid (SBF) in a presence of 0.2 g/l human serum albumin (HAS) was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The synergetic effect of albumin and doped elements on the degradation of Ti was studied. As a result of these investigations, it is revealed that: fluoride, copper and magnesium were successfully incorporated into apatite lattice structure. The additions of ions in FHA crystal matrix reduced the crystallite size, increased the crystallinity and changed the structure of F-hydroxyapatite. All the electrochemical techniques employed demonstrated that the coatings that were produced offered superior protection against corrosion for titanium when exposed to artificial body fluids. The nano-Mg-FHA coating improves effective protection to Ti and presents the highest corrosion resistance. The outcomes of this investigation were also compared with already published works to validate the research results.