Preparation of cerium myristate (super)hydrophobic coating by one-step electrodeposition and its protective properties on aluminum alloys

This paper prepared cerium myristate coating on a 6061 aluminum alloy surface using a one-step cathode electrodeposition method under different deposition times and deposition current densities. The results show that the corrosion resistance of the aluminum alloy covered with the obtained coating is higher than that of the blank aluminum alloy. Moreover, the corrosion resistance of the coatings obtained at different deposition current densities increases first and then gradually stabilizes with the deposition time and finally shows a similar protection effect to the aluminum alloy. Then, the coating obtained at a lower deposition current density (0.5 mA/cm²) was systematically studied from an energy-saving perspective. Potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS) results show that the aluminum alloy's corrosion rate and corrosion trend in 3.5 wt% NaCl solution are reduced after the coating is covered. The protective effect of the coating on aluminum alloy reaches its maximum when the deposition time is 15 min. At this time, the corrosion current density of aluminum alloy is three majority orders lower than that of blank aluminum alloy, and the total corrosion resistance is two majority orders higher. Corrosion and pitting potential are about 140 mV more positive than blank aluminum alloy. The SEM and water contact angle (WCA) results show that the coating gradually transforms from a smooth and dense layer into a rough and loose porous layer with the extension of deposition time. When the deposition time reaches 15 min, the WCA of the coating can be 157.5°, showing superhydrophobicity. The stability test also found that the obtained coating has good mechanical wear resistance, UV light resistance stability, and anti-corrosion durability. Finally, based on the changes in morphology and corrosion resistance of the coatings obtained at the deposition current density of 0.5 mA/cm² under different deposition times, it is speculated that the superhydrophobic coatings obtained by electrodeposition may consist of a dense inner layer and a loose porous outer layer.