Fabrication of hydrophobic coating on electrolytic manganese surface for enhancing corrosion resistance

Abstract

Two kinds of hydrophobic coating, lauric diethanolamide (LDEA) hydrophobic coating, lauric diethanolamide and stearic acid (LDEA-SA) hydrophobic coating were fabricated on electrolytic manganese by immersion method. Studies of experimental variables, such as immersion time and solution concentration, had been performed to better optimize hydrophobic coatings with the desired corrosion resistance. The wettability, morphology and composition of the hydrophobic coatings were characterized by contact angle measurement (CA), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The corrosion behavior of the samples was investigated by polarization curve test and electrochemical impedance spectroscopy (EIS). The results revealed that the LDEA-SA hydrophobic coating showed better corrosion resistance and hydrophobicity. Compared with the manganese substrate, the corrosion current density of the LDEA-SA hydrophobic coating decreased from 3.782 × 10−4 to 1.153 × 10-5 A/cm2, and the contact angle increased from 41° to 124°. The complete coating morphology was more conducive to enhancing the corrosion resistance of the sample.