Influence of SiO, Substitution on Corrosion Behavior of Sol-gel TiO,Coating on Mild Steel

Abstract

Titania with and without silica additions were deposited on mild steel (MS) by solgel method to enlir.-ince its corrosion resistance A conversion coating was applied on MS substrate prior to sot-gel coating to control the substrate's oxidation during heat treatment of the coating. The Ti0,-SiO2 coatings (SiO, = 0,10, 30 and 50 mor/o) were characterized by X-ray diffraction Corrosion and Surface Engineering Division„ FT-IR, SEM and contact angle measurement. The corrosion resistance of sot-gel coatings was evaluated in 3.5% NaCI solution by open-circuit potential (OCP), electrochemical impedance and potentiodynamic polarization techniques. The so!-gel coatings exhibited a barrier type protection and reduced corrosion current density of the substrate by 4 orders of magnitude.Corrosion resistance of coating is reduced with increase in SiO, addition in Ti02 coating matrix.