Superhydrophobic Surfaces on Light Alloy Substrates Fabricated by a Versatile Process and Their Corrosion Protection

Abstract

After hydrothermally treated in H2O (for Mg alloy and Al alloy) or H2O2 (for Ti alloy), microstructured oxide or hydroxide layers were formed on light alloy substrates, which further served as the active layers to boost the self-assembling of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) and finally endowed the substrates with unique wettability, that is, superhydrophobicity. For convenience, the so-fabricated superhyrdophobic surfaces (SHS) were abridged as HT-SHS. For comparison, SHS coded as CE-SHS were also prepared based on chemical etching in acid and succedent surface passivation with PFOTES. To reveal the corrosion protection of these SHS, potentiodynamic polarization measurements in NaCl solution (3.5 wt %) were performed. Moreover, to reflect the long-term stability of these SHS, SHS samples were immersed into NaCl solution and the surface wettability was monitored. Experimental results indicated that HT-SHS was much more stable and effective in corrosion protection as compared with CE-SHS. The enhancement was most likely due to the hydrothermally generated oxide layer by the following tow aspects: on one hand, oxide layer itself can lower the corrosion due to its barrier effect; on the other hand, stronger interfacial bonding is expected between oxide layer and PFOTES molecules.

Superhydrophobic surfaces for corrosion protection: a review of recent progresses and future directions

“…53,54 Hydrothermal method Similar to the two methods above, the hydrothermal method is another important top-down approach for fabrication of superhydrophobic anticorrosive surfaces. [55][56][57][58][59][60][61] Here, the surface microstructures are synthesized from an aqueous environment under elevated heat and/or pressure. Hydrothermal methods are considered more environmentally friendly since the chemical used to create surface microstructures is only H 2 O or dilute H 2 O 2 .…”

“…Hydrothermal methods are considered more environmentally friendly since the chemical used to create surface microstructures is only H 2 O or dilute H 2 O 2 . 58 Li et al, reported a hydrothermal method to produce superhydrophobic zinc surface using a two-step approach: (1) autoclaving zinc in pure water at 120°C for surface roughening; (2) immersing in ethanol solution containing 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) for surface hydrophobization. 57 From the viewpoint of corrosion protection, hydrothermal methods are also more favored than chemical etching because of the formation of oxide or hydroxide protective layers.…”

“…For example, Ou et al used hydrothermal methods to prepare oxide or hydroxide layers on the surface of light alloys, such as magnesium, aluminum, and titanium alloys and grafted with PFOTES to endow superhydrophobicity. 58 Separately, they applied the acid etching method to produce roughness on the surface of these alloys. After treatment with perfluorooctyl trichlorosilane (PFOTS), superhydrophobic surfaces were also obtained.…”

Composite coating with synergistic effect of biomimetic epoxy thermoset morphology and incorporated superhydrophobic silica for corrosion protection

“…In order to facilitate the corrosion protection of various metallic substrates, versatile alternative practical coatings are being continuously developed such as conducting/ electroactive polymers, [10,11] conventional polymers containing filler with large aspect ratio [12,13] and polymer coatings with superhydrophobic surface [14,15]. Recently, great attention is paid to the potential of applications on bio-mimetic materials with super-hydrophobic surfaces structure due to their diverse potential and unprecedented hierarchical surfaces [16][17][18][19][20][21][22][23][24][25][26].…”

UV-curable nanocasting technique to prepare bioinspired superhydrophobic organic-inorganic composite anticorrosion coatings

“…Water drops on such surfaces cannot penetrate the micro-or nanostructures and wet the surface, resulting in extremely high contact angles; thus, these naturally occurring leaves exhibit considerable superhydrophobicity. Numerous methods, including photolithography [6], plasma treatment [7], templates [8], chemical deposition [9], solgel processes [10], chemical vapor deposition (CVD) [11], casting, and chemical etching [12], have been utilized to fabricate superhydrophobic surfaces. Several studies have been reported on using polymers and polymer nanocomposites for various applications such as fabricating hydrophobic/superhydrophobic surfaces [13][14][15][16][17][18][19][20][21].…”