Bioactive coatings deposited on titanium alloys.

C. GARCÍA,; A. DURÁN,; S. CERÉ

Maringá, Brasil

Congreso; International Symposium of Non Crystalline Solids and VII Brazilian Symposium on Glass and Related Materials.; 2005

Metals are used in the human body mainly for orthopaedics purposes and their degradation by wear and or corrosion must be negligible. However, metals present some problems such as the in situ degradation and the requirement of the external fixation. One of the ways of minimise corrosion products release from the implant to the surrounding tissue consists in applying a protective coating. This protective coating may be functionalised with a bioactive material, able to generate a natural bonding to the living tissue.  This work describes the development of a double layer coating obtained by the sol-gel technique containing bioactive glass, glass-ceramic and hydroxyapatite particles in hybrid methyl-triethoxisilane (MTES) and tetraethilorthosilicate (TEOS) acidic sol, applied by the dip coating method on titanium alloy (ASTM F 67). The electrochemical behaviour of the coated samples was evaluated by potentiodynamic polarization curves and electrochemical impedance spectroscopy assays (EIS) using simulated body fluid (SBF) as electrolyte. In vitro bioactivity tests were performed by evaluating the samples surface after soaking the coated samples in SBF at 37°C for various periods of time. The application of double coated samples containing particles on the titanium alloy show an improvement in the corrosion resistance in the tested period of time. This improvement could be due to the reaction of the particles with the physiological medium, which nucleates the formation of calcium phosphate crystals, and blocks the porosity of the coating (initial or post-formed).