Cailiao Baohu (Jan 2024)
Study on Preparation and Corrosion Resistance of Cu-MOF-SA Superhydrophobic Films on AZ31 Magnesium Alloy
Abstract
Corrosion is one of the key technical challenges affecting the large-scale application of magnesium and its alloys.Superhydrophobic surfaces are an effective way to improve the corrosion resistance of magnesium alloys，as they can effectively isolate direct contact between the metal substrate from the corrosive medium，thereby reducing the corrosion rate.A superhydrophobic film composed of Copper-Metal Organic Framework-Stearic Acid (Cu-MOF-SA) was successfully fabricated on an AZ31 magnesium alloy substrate using a one-step electrodeposition method.Comprehensive studies were conducted on the corrosion resistance，chemical stability and thermal stability of the superhydrophobic film.Results showed that the water contact angle of the superhydrophobic film surface reached up to 158°；the sample coated by superhydrophobic film exhibited good corrosion resistance in a 3.5%NaCl solution.Compared with the AZ31 magnesium substrate，the corrosion potential of the superhydrophobic film increased by 0.24 V，and the corrosion current density was reduced by one order of magnitude.The water contact angle of the superhydrophobic film remained larger than 135° after being immersed in solutions with a pH of 1～14 for 24 h.The corrosion potential of superhydrophobic film after being immersed in solution with a pH of 1 for 24 h was 0.21 V higher than that of the AZ31 magnesium substrate.After being insulated in air at 20 ～90 ℃for 24 h，the water contact angle of the Cu-MOF-SA superhydrophobic film’s surface remained above 154°.Additionally，after being insulated in air at 80 ℃for 24 h，the corrosion potential of the superhydrophobic film was 0.22 V higher than that of the AZ31 magnesium substrate.The corrosion current density of the superhydrophobic film was one order of magnitude smaller than that of AZ31 magnesium alloy substrate.In brief，the Cu-MOF-SA superhydrophobic film fabricated in this study demonstrated excellent superhydrophobicity and corrosion resistance.
