Bioactive coatings prepared by sol–gel on stainless steel 316L

This work describes the development and characterization of coatings obtained by the sol–gel technique, applied on stainless steel used in orthopaedic surgery. These coatings are applied to reduce metal corrosion and adverse reactions when implanted. Hybrid coatings of silica containing hydroxyapatite, bioactive glass and glass–ceramic particles were prepared and applied on metal substrates. The coated samples were further tested in vitro to study their electrochemical properties and bioactive response. The electrochemical properties were evaluated by means of potentiodynamic polarization assays using simulated body fluid (SBF) as electrolyte. In vitro bioactivity tests were performed by soaking the coated samples in SBF at 37 °C with a ratio sample area/fluid volume of 0.35 cm/ml for different periods. The coatings improve corrosion resistance of the steel substrate and in vitro tests revealed that all the films show signs of bioactivity.