Antireflection Property and Corrosion Resistance of Black Ceramic Superhydrophobic Coatings on Aluminum Alloy

Abstract

In this article, a black ceramic coating is produced on the surface of 7075 aluminum alloy by plasma electrolytic oxidation (PEO) in a silicate electrolyte containing ammonium metavanadate (NH4VO3). The PEO processed sample is further subjected to hydrothermal treatment (HT) and fluorination treatment (FT) to obtain a superhydrophobic PEO/HT/FT coating. The 21‐day air durability test and the tape stripping test show that the superhydrophobic surface shows excellent air durability and mechanical durability. The antireflection test study shows that the average antireflection of the PEO/HT/FT coating is as high as 96.6% in the wavelength range between 400 and 1000 nm. Furthermore, electrochemical test results show that the corrosion current density of the PEO/HT/FT coating decreases to 2.49 × 10−6 A cm−2, three orders of magnitude lower than the aluminum substrate, and the anticorrosion efficiency is as high as 99.87%. The preparation of PEO/HT/FT coating provides more methods for the wide application of Al alloy in aerospace field.