Robust superhydrophobic SiO2/epoxy composite coating prepared by one-step spraying method for corrosion protection of aluminum alloy: Experimental and theoretical studies

• Published in: Materials & design 2023-04, Vol.228, p.111833, Article 111833
• Main Authors: Zhang, Xue-Fen, Li, Xu-Dong, Wang, Ning, Liu, Yong-Jiang, Tian, Feng, Wang, Chen-Xiang
• Format: Article
• Language: English
• Subjects: Corrosion resistance; Mechanical resistance; Molecular dynamics simulation; SiO2; Superhydrophobic
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2023.111833

[Display omitted] •Robust superhydrophobic SiO2/epoxy coating was prepared by a one-step spraying strategy.•The superhydrophobic coating shows improved mechanical resistance and corrosion inhibition.•The mechanisms of performance enhancement were revealed through experiments and molecular simulations.•The superhydrophobic coating exhibits good chemical stability and hydrophobic repair properties. In this work, a robust epoxy adhesive (EP) @ superhydrophobic SiO2 (SH-SiO2)-based superhydrophobic coating was prepared on the aluminum substrate by a simple one-step spraying strategy. The prepared EP@SH-SiO2 coating exhibits hierarchical micro/nanostructures and is capable of maintaining a contact angle of more than 150° after 1000 cm of abrasion length and 80 tape-peeling repetitions. Molecular dynamics (MD) simulations and quantum mechanics calculations show that the improved mechanical resistance is attributed to the enhanced interfacial interaction between the EP@SH-SiO2 coating and the underlying substrate induced by the epoxy adhesive. Electrochemical measurements in 3.5 wt% NaCl solution show the corrosion inhibition efficiency of the EP@SH-SiO2 coating reaches up to 99.99%, and even after 8 days of immersion, the low frequency impedance modulus of the EP@SH-SiO2 sample is still ∼1 order of magnitude higher than that bare aluminum, demonstrating excellent long-term corrosion protection. The diffusion behavior of the corrosive medium in the EP@SH-SiO2 coating was revealed by MD simulation to support the experimental results. Additionally, the EP@SH-SiO2 coating exhibits good chemical stability and hydrophobic repair properties. This work will provide a new perspective for the preparation and study of robust superhydrophobic aluminum for corrosion protection properties.