Synthesis and corrosion resistance evaluation of coatings of SiO2-TiO2-ZrO2-BiO2 on 316L stainless produced by sol-gel

This report show the synthesis and corrosion resistance of SiO2-TiO2-ZrO2-BiO2 coatings deposited by spin-coating on AISI 316L stainless steel. The soles were prepared from a mixture of organic precursors, such as 98% tetraethoxysilane (TEOS), titanium tetrabutoxide (TBT) 97%, Zirconium (IV) butoxide (TBZ) 80% in 1-butanol solution and bismuth penta nitrate-hydrate Bi (NO3)(3)*5H(2)O. The coatings were evaluated by potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) test in an electrolytic solution of 3.5% Wt NaCl + 0.5 MH2SO4. The soles prepared were studied trough rheological, pH as a time function, Fourier Transform Infrared Spectroscopy (FTIR) and differential scanning calorimetry (DSC) analysis. The coating were characterized by X ray diffraction (XRD), scanning electron microscopy (SEM) and dispersive energy spectroscopy (EDX), X ray fluorescence (XRF) and adhesion measurements. The results showed that the films offer good corrosion resistance on the metal substrate, decreasing current densities up to one order of magnitude. (C) 2018 SECV. Published by Elsevier Espana, S.L.U.