Surface modification of 316L stainless steel by Sol-Gel method

Abstract

Medical implants made from 316L stainless steel have been used widely and successfully for various types of dental and orthopaedic implants. It is believed that oxide films covering implant surfaces are of crucial importance for biocompatibility and successful osseo-integration. A uniform TiO2 coating on 316L stainless steel coupons has been prepareds using sols-gel methodology followed by hydrothermals post-treatmentsk. Sol-gel process is one of the best wet chemical routes to deposit the coating with convenient production of required thin films and controlled distribution of pore-size, processed at relatively lower temperature than any other conventional coating methods. Different coating thicknesses have been achieved by coating TiO2 sol-gel on samples having different surface finish. The structure and morphology of thef coatingsr weref analyzedh using optical microscope and X-rayf diffractionh technique. When the samples are observed under optical microscope, the results indicate that TiO2 sol-gel coating on 316l stainless steel is uniform and dense; we can see a crack-free surface. The XRD patterns show different strong peaks of TiO2 coating on the substrate. Bioactivity study of the coated samples is done by dipping them in SBF solution. We observe firmly attached hydroxy apatite layer on the TiO2 coated substrate and XRD patterns show the presence of calcium phosphate which increases the osseo-integration. The surface free energy have been calculated for the steel samples having different surface finish and also the contact angle has been measured. Ground samples show the best characteristics with enhanced roughness.