Preparation of Superhydrophobic Coating on Aluminum Alloy by Dip - Coating Method and Its Corrosion Resistance

Abstract

For improving the corrosion resistance of aluminum alloy, a superhydrophobic coating was prepared on the surface of 6063 aluminum alloy by dip - coating method. The microscopic morphology, composition and roughness of the coating were analyzed by scanning electron microscope, energy dispersive spectrometer and 3D optical profiler. Meanwhile, the bonding performance of the coating to the substrate was evaluated by tape test, and the corrosion behavior of the coating was studied by electrochemical potentiodynamic scanning polarization curve and AC impedance spectroscopy. Results showed that the coating had a micro/nano structure and showed a superhydrophobic characteristic with a water contact angle up to 152.1°. The corrosion resistance of the coating was excellent in 3.5% NaCl solution. In comparison with the substrate, the corrosion potential of the coating shifted positively 407 mV, the corrosion current density decreased by three orders of magnitude, and the impedance modulus in the low - frequency region increased by seven orders of magnitude, indicating that the superhydrophobic coating could significantly improve the corrosion resistance of 6063 aluminum alloy.

Keywords

• aluminum alloy|dip - coating method|fluorocarbon coating|superhydrophobicity|corrosion resistance