Preparation of Superhydrophobic Coating on Q235 Steel and its Corrosion Resistance in Simulated Concrete Pore Solution

Phosphate coating was prepared on the surface of Q235 steel through phosphate treatment as the bottom layer, and then the phosphate coating was uniformly covered with modified TiO2 sol which was closely combined with the phosphate coating to form a superhydrophobic coating. Scanning electron microscopy, energy spectrometer, droplet contact angle meter and electrochemical workstation were used to characterize and analyze the surface morphology, composition, surface hydrophobicity and corrosion resistance of the superhydrophobic coating in simulated concrete pore solution respectively. The results show that the superhydrophobic coating has a kind of micro and nano structure, and the main composition are Zn, O, P, Ti, Si and C elements. The sperhydrophobic coating is closely combined with Q235 steel to reduce the surface energy and maintain superhydrophobic state. The corrosion current density and corrosion weight gain of the superhydrophobic Q235 steel are significantly lower than that of bare Q235 steel immersed in simulated concrete pore solution for the same time. The superhydrophobic coating formed on Q235 steel can effectively inhibit the corrosion reaction with its high binding strength and good surface hydrophobic action, and shows an ideal corrosion resistance in simulated concrete pore solution.