Oxygen vacancy induced superhydrophobicity of air plasma spraying deposited Y2O3 coatings

Air plasma spraying (APS) is widely used for preparing superhydrophobic rare earth oxide (SH-REO) coatings due to its advantages of capable for large-scale and fast deployment with low cost. However, the origin of the superhydrophobicity remains unclear, which has impeded the design and development of robust APS-deposited SH-REO coatings. In this work, by studying APS-deposited superhydrophobic yttrium oxide (SH-Y2O3) coatings, we found a close correlation between oxygen vacancy and surface adsorbed species. Our results suggest that oxygen vacancy introduced during APS makes the Y2O3 surface liable to the adsorption of nonpolarized, hydrocarbon molecules, which contributes to a low-energy surface. Therefore, we showed the crucial role of oxygen vacancy in the acquirement of reliable SH-REO coatings.