Preparation of anti-corrosion superhydrophobic coatings by an Fe-based micro/nano composite electro-brush plating and blackening process

Superhydrophobic coatings with high strength and corrosion resistance on hard metal surfaces have been attracting significant attention in recent years. In this paper, a quick and easy method using Fe-based micro/nano composite electro-brush plating and subsequent modification with stearic acid was established for fabricating superhydrophobic surfaces on A3 steel plates. The processing parameters including the working voltage, the brushing speed and the micro-TiO2 particle concentration were studied to determine their influences on the wettability. A blackening process was conducted to further improve the corrosion resistance of the Fe-based plating layer with high water repellency. The surface morphology and chemical composition were analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Corrosion resistance ability was measured using an electrochemical workstation. The results suggested that: the rough structure of the superhydrophobic coatings can be successfully fabricated by electro-brush plating technology with appropriate parameters; after post-treatment by stearic acid, the contact angle of the composite coating was up to 156 degrees and the sliding angle was even as low as 1 degrees under the optimal process. Meanwhile blackening treated superhydrophobic coatings still maintained excellent superhydrophobicity and the self-corrosion potential improved by 0.116 V compared to the untreated brush plating layer and the prepared superhydrophobic coatings achieved an excellent long term anti-corrosion performance.