Sol-gel coatings on 316L steel for clinical applications

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