Sol-gel coatings on 316L steel for clinical applications

SiO2 and SiO2-CaO-P2O5 coatings have been prepared by dipping electropolish ed stainless steel 316L samples and microscope glass slides in three differ ent sol-gel solutions. Multilayered dense SiO2 coatings, and thick silica f ilms obtained from equimolar contents of TEOS and MTES were used. The latte r were able to strongly reduce both the corrosion attack on the steel and t he iron diffusion to the sample surface. SiO2-CaO-P2O5 coatings were also o btained and applied onto the silica films, in order to provide a bioactive external surface for contact with living tissue. In-vitro evaluation of the se coatings and films is discussed.