Corrosion behavior and mechanical properties of bioactive sol-gel coatings on titanium implants

Organic–inorganic hybrid coatings based on zirconia and poly (ε-caprolactone) (PCL) were prepared by means of sol-gel dip-coating technique and used to coat titanium grade 4 implants (Ti-4) in order to improve their wear and corrosion resistance. The coating chemical composition has been analysed by ATR-FTIR. fluence of the PCL amount has been investigated on the microstructure, mechanical properties of the coatings and their ability to inhibit the corrosion of titanium. alysis has shown that all coatings have a nanostructured nature and that the films with high PCL content are crack-free. ical properties of the coatings have been studied using scratch and nano-indentation tests. The results have shown that the Youngʹs modulus of the coatings decreases in presence of large amounts of the organic phase, and that PCL content affects also the adhesion of the coatings to the underlying Ti-4 substrate. However, the presence of cracks on the PCL-free coatings affects severely the mechanical response of the samples at high loads. ectrochemical behavior and corrosion resistance of the coated and uncoated substrate has been investigated by polarization tests. The results have shown that both the coatings with or without PCL donʹt affect significantly the already excellent passivation properties of titanium.