Bioactive coatings for functionalization of the medical implants

Titanium (Ti) and its alloys are widely used as implant materials because of excellent mechanical properties and corrosion resistance. However, Ti and its alloys are bioinert. In order to improve the bone bonding ability, titanium is generaly coated with osteoconductive biomaterials such as CaP ceramics. To enhance the biocompability, CaP coating is generally modified by doping with trace amounts of beneficial elements (Mg2+, Sr2+, Na+, K+, F−, Zn+2) which are existed in natural bones. Although the amount of these substitutions is small, they play important roles in the biological activity and interaction between the bone mineral and CaP based implant materials. Several calcium phosphate coating techniques have been used as plasma spraying, biomimetic deposition, sol-gel, and electrochemical deposition. The electrochemical deposition has a variety of advantages such as low process temperature, ability to deposit on porous or complex shape of substrate, low cost and easiness of thickness control. The aim of the study was to investigate the effect of Mg-substitution on corrosion and bioactivity properties of CaP coatings on Ti6Al4V substrates via electrodeposition technique. Chemical and morphological characterizations of the coatings were examined by using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Additionally, corrosion properties of the coatings were studied electrochemically by potentiodynamic polarization technique in simulated body fluid (SBF) at 36±1°C and bioactivity properties of the coatings investigated in SBF with varying time 1, 7 and 14 days. In conclusion, Mg-subtitution, while enhancing the bioactivity properties of the coatings, there is no affirmative effect on corrosion properties of the coatings.