Corrosion resistance of ZrO2-TiO2 nanocomposite multilayer thin films coated on carbon steel in hydrochloric acid solution

This work reports the achievement of preparing of x% zirconia (ZrO2)-titania (TiO2) composite coatings with different ZrO2 percent on the carbon steel by dipping substrates in sol-gel solutions. The prepared coated samples were investigated by various surface techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDAX). Open-circuit potential (OCP), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods were employed to investigate the corrosion resistance of the coated carbon steel substrates in 1.0 M HCl solution at 50 degrees C. The data showed that, the corrosion protection property is not always proportional to the percent of ZrO2. It can be inferred that there is an optimum percent (10%ZrO2) for beneficial effects of loading ZrO2 on the protection efficiency (98.70%), while higher loading percent of ZrO2 in the sol-gel coating leads to the formation of a fragile film with poor barrier properties. EDAX/SEM suggests that the metal surface was protected through coating with ZrO2-TiO2 composite films. (C) 2015 Elsevier Inc. All rights reserved.