Double layer bioglass-silica coatings on 316L stainless steel by sol–gel method

The application of bioglass coatings on metallic implants provides link between bone and materials and prevents corrosion of metallic implants in body fluid. Therefore, in this research, 45S5 bioglass-silica coatings on 316L stainless steel were prepared by the sol–gel method and were characterized by different techniques. According to X-ray diffraction (XRD) results, by sintering 45S5 bioglass at 600 °C for 5 h, coatings containing both amorphous phase and Na2Ca2Si3O9 crystalline phase were obtained. Scanning electron microscopy (SEM) results showed that coatings prepared via appropriate sol aging and substrate preparations are crack-free. Potentiodynamic polarization tests in simulated body fluid (SBF) showed that coatings improve corrosion resistance of substrates, significantly. Further, bioactivity was considered during 30 days of immersion in SBF at 37 °C by atomic absorption spectroscopy (AAS), XRD, SEM and potentiodynamic polarization tests that demonstrated the growth of amorphous apatite, hydroxyapatite (HA) and CaSiO3 film on coatings.