Rapid transition from superhydrophilic to superhydrophobic of hierarchical Ni-CeO2 coating via vacuum heating on steel substrate for anti-scaling property

Preparation of superhydrophobic surfaces on steel substrate usually required the low-energy material modification. Although some reportedly hierarchically structured coatings achieved superhydrophobicity after only storage in air without low-energy modification, the storage time usually required more than seven days. Herein, the hierarchical Ni-CeO2 coating were prepared on the steel substrate by one-step electrodeposition, and this coating transformed from superhydrophilic to superhydrophobic with the water contact angle of 153° and the roll-off angle of 4.3° by heating treatment under a low vacuum for 12 h. For comparation, we also prepared an electrodeposited Ni coating on the steel substrate. However, it only achieved hydrophobicity with the water contact angle of 129.2° after heating treatment under a low vacuum for 12 h. In this study, the microstructure and addition of cerium dioxide on the adsorption behavior of two coatings were investigated. The transformation process of wettability was analyzed utilizing adsorption theory. The results showed that the Ni-CeO2 coating demonstrated excellent anti-scaling performance under static and dynamic conditions, with a corrosion inhibition rate of greater than 95%. The stability of the coating was also demonstrated to be strong. This research presents a shortened preparation method for the creation of no-modification superhydrophobic surfaces and provides technical and theoretical support for the development of such surfaces. Moreover, the treatment significantly reduced the transition time for wettability without modification.