Construction of Superhydrophobic Coatings on Hot-Dip Galvanized Surface and Its Corrosion Resistance Properties

To construct a corrosion-resistant superhydrophobic coating on the hot-dip galvanized surface， a simple soaking method was utilized to roughen the hot-dip galvanized surface，and the surface was further modified with an alcohol solution of stearic acid.The influences of roughening time and modification time on the coating’s corrosion resistance and superhydrophobic performance were investigated by orthogonal experiments， and the surface composition of the coating was confirmed via infrared spectrum analysis， thermogravimetric analysis and X-ray photoelectron spectroscopy analysis.Moreover， the morphology of the coating was observed using a scanning electron microscope， and the formation mechanism of the superhydrophobic coating was analyzed.The corrosion resistance of the coating was analyzed by electrochemical testing methods，and the freezing resistance stability of the coating was tested.Results showed that the as-obtained optimal parameters were the roughening time of 4 h and modification time of 20 min，and the surface of the superhydrophobic coating had a clustered petal-like structure.Meanwhile，the superhydrophobic coating displayed remarkable corrosion resistance and stability， with an AC impedance value of 7×106 Ω∙cm2， which was four orders of magnitude higher than the original hot-dip galvanized sample.In addition， the superhydrophobic coating exhibited good freezing stability.