Controllable superhydrophobic surfaces with tunable adhesion on Mg alloys by a simple etching method and its corrosion inhibition performance

Through a simple chemical etching and surface modification, superhydrophobic surfaces with tunable water adhesion were prepared on rolled Mg-3Al-1Zn (AZ31) and Mg-9Al-1Zn (AZ91) alloy sheets. The different water adhesion is described by three different wetting model, i.e. Wenzel, Cassie impregnating, and Cassie model. An in-depth investigation on anti-corrosion performances of low adhesive superhydrophobic AZ31 and AZ91 surfaces reveals that dense microstructure can effectively improve the stability of Cassie state, thus facilitating durable anti-corrosion ability. Simultaneously, the superhydrophobic surfaces with tunable water adhesion are demonstrated to be feasible in the application of low-loss transport of microdroplet. In addition, the as-fabricated superhydrophobic surfaces show high-temperature stability and chemical stability in a large range of temperature and pH, respectively. It is expected that this research can shed light on designing new anti-corrosion and tunable adhesive superhydrophobic surfaces, and as-fabricated superhydrophobic Mg alloys are promising in medical instruments, transport systems, micro-fluidic devices, and so on.