Study on Protective Performance of Urushiol Titanium Coating in the Simulated High Temperature and CO₂ Environment

Abstract

For improving the corrosion resistance of carbon steel in the saline medium with high temperature and CO2-containing environment, tetrabutyl titanate was used to crosslink with urushiol under the compatibilization condition of propylene glycol methyl ether acetate to form a urushiol titanium coating, which was coated on carbon steel substrate surface for preparing high temperature resistant coating. Subsequently, thermogravimetry (TG) was employed to determine the thermal-resistant of urushiol titanium coating. The morphological and Fourier transform infrared spectroscopy (FTIR) were conducted to evaluate the protective capacity of the coating on carbon steel in simulated saline water by immersion test under high temperature, high pressure and CO2-containing medium. Moreover, electrochemical impedance spectroscopy (EIS) was utilized to evaluate the impedance change of coating in corrosive medium before and after immersion. Results showed that the thermal decomposition temperature of urushiol titanium coating achieved at 275.19 ℃. After immersed in simulated saline solution at 140 ℃ and 155 ℃ with CO2 pressure of 2 MPa for 30 d, the low-frequency impedance values of the coating could reach the respective magnitude of 1011 Ω·cm2 and 1010 Ω·cm2. Moreover, the valence bond characteristics of the coating did not change, and the surface morphology of coating was uniform and closely combined with the substrate, which indicated that the coating showed excellent protective performance against high temperature.

Keywords

• urushiol|organic titanium|heat-resistant coating|protective performance