Preparation of a superhydrophobic Ni/SH-SiO2 coating by one-step electrodeposition and an analysis of its anti-corrosion performance

Abstract

The two-step method limits the large-scale production of superhydrophobic coatings, while low hardness limits the practical application of superhydrophobic coatings. In this study, silane-modified SiO2 nanomaterials (SH-SiO2) were prepared first and then superhydrophobic coatings were prepared by one-step electrodeposition by adding modified materials. In addition, the nonwetting properties, microhardness, mechanical stability and corrosion resistance of pure Ni coatings, Ni/SiO2 coatings, and Ni/SH-SiO2 coatings were compared. The contact angle test shows that the water contact angle (WCA) of the Ni/SH-SiO2 coating can reach 153.858°. The microhardness test shows that the addition of SH-SiO2 can effectively improve the microhardness of the coating and the microhardness of the Ni/SH-SiO2 coating is increased by 76.14% relative to the Ni coating. When the abrasion length reaches 1000 mm, the change of the water contact angle of the Ni/SH-SiO2 coating is kept within 5%, which helps to further promote the practical application of superhydrophobic coatings. Electrochemical impedance spectroscopy tests were used to comprehensively evaluate the corrosion resistance of the coating. The results showed that in a 3.5 wt% NaCl solution, the impedance of the Ni/SH-SiO2 coating is an order of magnitude increase over the other two coatings. Overall, the Ni/SH-SiO2 coatings have excellent corrosion resistance, good hardness and hydrophobicity, and their simple preparation method has positive implications for the large-scale production of superhydrophobic coatings.