3.5 Waterbased Superhydrophobic Coating on Al Alloy with Excellent Anticorrosion Performance
(Room 237-239)
09 Apr 18
4:30 PM
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5:00 PM
Tracks:
Session 3: Functional and Smart Coatings
Aluminum (Al) and its alloys are important engineering materials in modern industry due to their numerous advantages and have been widely used in various fields, including aerospace, marine, civilian industries and so on. However, they are prone to corrosion and contamination under harsh environment conditions, particularly in marine environment when exposed to salty water or moisture for quite a long time, which can adversely affect their aesthetic appearance and desired functionalities or even cause economic losses and serious accidents. To prevent or delay the corrosion, the hydrophilic nature of Al and its alloy surfaces can be transformed to be hydrophobic or superhydrophobic. In this study, we reported an environmentally friendly water-based bio-epoxy superhydrophobic coating (WBSC) without using volatile solvents. The coating is composed of bio-epoxy resin, nano silica, as well as hydrophobic curing agent, applied by spin method on Al alloy substrates. The surface morphology and roughness were characterized by a field emission scanning electron microscope (FESEM) and an atomic force microscope (AFM). The WBSC with 40 wt.% nano silica loading displays a water contact angle (CA) as high as 165.8 ± 3.3° and a sliding angle (SA) as low as 5.3 ± 2.5°. Electrochemical measurement results showed that the as-prepared WBSC has a decrease of 3 orders of magnitude in the corrosion current density (Jcorr) and significant shift from −1.16 V to −0.708 V in the corrosion potential (Ecorr), indicating excellent corrosion resistance. The WBSC was further proven to function well after immersion in common solvents including deionized (DI) water, ethanol and acetone for 48 h. In addition, the as-prepared WBSC also showed good self-cleaning performance. The developed coating is green and no harm to human health and environment. The facile and eco-friendly process is of great importance for many industrial applications which can provide an attractive way towards anti-wetting surfaces for corrosion protection and self-cleaning effect on a variety of engineering substrates.
Key words: Water-based; Bio-epoxy; Superhydrophobic coating; Al alloy; Corrosion resistance; Self-cleaning