Biovitroceramic Coatings on Modified Surface of 316L Austenitic Stainless Steel

Austenitic stainless steel 316L is widely used in implantology due to its biocompatibility, a lower price than titanium and because can be easily mechanically machined. The drawback is due to the fact that toxic nickel and chromium ions are released into human body fluids. Our proposal is to coat 316L austenitic stainless steel with biovitroceramic layers made of oxide system SiO2, B2O3, Na2O, CaO, TiO2, P2O5, K2O, Li2O and MgO by means of an enamelling procedure in order to hinder the release of Ni and Cr ions from the metallic implant surface toward the tissue around the implant. In order to achieve a firm adherence of biovitroceramic layer onto the metal, with an optimal composition for biocompatibility and bioactivity, we have modified the steel surface by a titanizing thermochemical treatment. The adherence of the biovitroceramic layer to the 316L stainless steel with modified surface is very good. The biovitroceramic coating - metallic substrate couple was studied by optical microscopy, electron microscopy (SEM and EDAX), X-ray diffraction analysis and microhardness trials.