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

•Sol–gel TiO2 doped with ZrO2 films deposited on carbon steel substrate•XRD measurements of x wt.% ZrO2–TiO2 showed the (101) peaks broader than that of TiO2.•SEM results proved that, the cracking decreases with the number of layers.•The prepared films can improve the corrosion resistance of the carbon steel substrate.•10%ZrO2 loading is the optimal percent for useful effects on the corrosion resistance.

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 °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.

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