Preparation and Corrosion Resistance of Superhydrophobic Ni- P-Al2O3 Coating on Pipeline Steel in simulated alkaline soil solution

摘要

Superhydrophobic coating with good corrosion resistance has become a research hotspot. The nano-Ni- P-Al2O3 composite coating was prepared on the surface of pipeline steel by electrodeposition technology with nano-Al2O3 particles into the bath, which aimed to reduce the corrosion of pipeline steel in the alkaline soil environment. The micromorphologies, hydrophobicity, and corrosion resistance of the electrodeposited composite coatings at different concentrations of nano-Al2O3 (0, 5, 10, and 15 g/L) were studied by scanning electron microscope (SEM), energy disperse spectroscopy-mapping (EDSmapping), contact angle, and electrochemical measurements. The papillary protrudes grew on the surface of the coating with the increase of the nano-Al2O3 content. The coating surface was uniform and compact when the nano-Al2O3 particle concentration was 15 g/L. The nano-Ni-P-Al2O3 composite coating was superhydrophobic, and the maximum contact Angle was 158.3°. The electrochemical test results showed that the shape characteristics of EIS and potentiodynamic polarization curve of the coating were not changed by the content of nano-Al2O3. With the increase of the nano-Al2O3 concentration, the capacitive arc radius and Ecorr of the composite coating increased, while Icorr decreased, which indicated that the corrosion resistance of the composite coating in the simulated soil solution was gradually enhanced. The coating with 15 g/L nano-Al2O3 particles had the best corrosion resistance, and the corrosion rate was significantly lower than that of X100 pipeline steel.