Theoretical, fundamental and experimental study of Liquid-repellency and corrosion resistance of fabricated superamphiphobic surface on Al alloy 2024

Abstract A superamphiphobic surface was fabricated on Al alloy 2024 (AA 2024) by a four-step process including electroetching, anodizing, sealing, and surface chemical modification. Hydrophobicity of the surface was investigated by water contact angle (WCA) and sliding angle (SA) tests and results of 176.1° and 3.1° were obtained, respectively. Furthermore, oil-repellency of the surface was considered by measurement of oil contact angle and sliding angles of glycerol (163.9°–4.4°), ethylene glycerol (157.6°–4.9°), hexadecane (155.3°–5.4°), n-decane (152.7°–7.2°), and octane (150.4°–8.1°). The effect of time and voltage of anodization on the superamphiphobicity of the surface was studied and optimal operating conditions of 30 V and 3 min were determined respectively. The surface was further characterized by FESEM and AFM. Furthermore, the corrosion resistance of the superamphiphobic surface was investigated through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The superamphiphobicity of the surface enhanced the corrosion resistance of the AA 2024 due to the decrease in corrosion rate from 0.1456 (mpy) for untreated AA 2024 to 0.0092 (mpy) and increase of impedance from 2.91 × 10+5 to 6.11 × 10+8 Ω.cm2 respectively for the superamphiphobic AA 2024 sample.