We describe the technologically simple route for the fabrication of the superhydrophobic coatings on top of wrought magnesium alloy MA8 based on nanosecond laser processing followed by the chemical vapor deposition of fluorosilane. The chemical and phase composition, surface morphologies, and variation of the coating wettability during prolonged contact with 0.5 NaCl solution or with salt aerosol were characterized using X-ray diffraction, FT-IR spectroscopy, scanning electron microscopy measurements, and the wettability analysis. The as-prepared coatings demonstrate corrosion current of more than eight orders of magnitude lower, while after 30 days of sample immersion into corrosive solution, the current was four orders of magnitude lower than that obtained for a polished sample which was for only 2 h in contact with electrolyte. The mechanisms of the protective activity of fabricated coatings were discussed.

The paper discusses the possibility of obtaining a uniformly inhomogeneous surface of aluminum alloy 6063 as a result of alkaline etching and laser processing. Further surface treatment with ethanol solutions of octadecylphosphonic (ODPA) and stearic acids leads to its superhydrophobization (SHP). The study of the degradation kinetics of SHP coatings in water and under conditions of neutral salt spray showed the high stability of ODPA films obtained on a laser-textured surface with an irregularities height of 9.82 μm. X-ray photoelectron spectroscopy (XPS) results showed that ODPA is chemisorbed on the alloy surface. High corrosion resistance of the surface with superhydrophobic layers confirmed by polarization measurements, electrochemical impedance spectroscopy (EIS) and corrosion tests.

The effect of sodium salts of some higher carboxylates on anodic magnesium dissolution in the borate buffer solution (pH 7.4) has been investigated. It has been demonstrated that the best protective...

—This paper considers the possibility of increasing the stability of SHP layers formed from ethanol solutions of oleic acid (OA) by layer-by-layer modification of the laser-textured surface of D16 alloy with ethanol solutions of trialkoxysilanes (vinyltrimethoxysilane (VS), octyltriethoxysilane (OTES)). It has been shown that OTES is more effective than VS in achieving the SHP state on the alloy surface. The protective ability of the coatings was evaluated by polarization measurements in an aqueous solution of 0.05 M NaCl and corrosion tests in a salt spray chamber. It was found that a two-stage modification of the alloy surface in OTES and OA solutions at C_in = 10 mmol/L enables it to surpass individual components in protective ability, while τ_cor = 498 h. It is significant that the SHP properties of the coating were maintained for 240 h of testing under neutral salt spray conditions.

The adsorption of oleylsarcosine sodium salt (OSS) from a neutral borate buffer solution on a pre-oxidized surface of aluminum alloy D16 at potential E=–0.3 V was studied by ellipsometry and electrochemical impedance spectroscopy (EIS). Adsorption isotherms of OSS have been obtained and can be adequately described by the full Temkin isotherm equation. The standard free energy of adsorption (–ΔG0ads) was calculated by using this equation. According to ellipsometric data, the value of 53.3 kJ/mol suggests the formation of a chemisorption OSS monolayer. Adsorption measurements by the EIS method turned out to be significantly less sensitive and adsorption was detected at higher OSS concentrations Cin≥0.1 mmol·L–1. It is not surprising that the value of ⁠–⁠ΔG0ads in this case does not exceed 30.3 kJ/mol. This value is 23 kJ/mol less than –ΔG0ads obtained by ellipsometric measurements and does not suggest that the EIS method detects OSS chemisorption. Probably, in this case, the formation of a polymolecular OSS film is determined, since the insufficiently sensitive the EIS method can register it only with thicker layers of physically adsorbed inhibitor on an electrode surface.