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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