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This research presents the development of a surface treatment for AZ91D magnesium alloy that exhibits both superhydrophobic and anticorrosive properties. Initially, a zinc-based phosphate film was deposited on the magnesium alloy surface. Subsequently, a composite coating with superhydrophobic properties was produced by surface modification using a fluorosilane-ethanol solution. The composite coating's microstructure, chemical composition, wettability, self-cleaning, and anti-corrosion properties were evaluated using scanning electron microscopy, a contact angle measurement instrument, and an electrochemical workstation. The results demonstrated that the main components of the composite coating were P, O, Zn, F, and C. The static contact angle reached 158°, providing superior self-cleaning and acid and alkali corrosion resistance. Additionally, the charge transfer resistance and coating resistance of the composite coating were significantly higher than those of the magnesium alloy substrate, effectively preventing corrosion and preserving the surface from fouling. [ABSTRACT FROM AUTHOR]

The high corrosion susceptibility of magnesium alloy has become a practical problem which restricts its wide application in many fields. To improve its surface properties, a composite coating has been successfully prepared on the surface of AZ91D magnesium alloy using a one‐step hydrothermal method. The coating surface possesses a dense structure in the form of scales and has an adhesion strength of 3B. The effect of different preparation conditions on the coating thickness and corrosion resistance is discussed. The coating heated at 180°C for 2 h showed the best corrosion resistance in a 3.5 wt% sodium chloride solution, with a reduction in corrosion current density of 5 orders of magnitude compared to the bare sample. This solution significantly improved the corrosion resistance of the magnesium alloy and helped to further realize the application of magnesium alloys in corrosive environments. [ABSTRACT FROM AUTHOR]

Magnesium alloys are widely used due to their excellent properties, but their corrosion resistance is limited by their high chemical activity. This paper proposes a one-step hydrothermal method with a relatively short reaction time and simple experimental steps for synthesising magnesium alloy coatings with good corrosion protection properties. The surface morphology, chemical composition and corrosion resistance of the in situ generated coatings were investigated using measurements such as field emission scanning electron microscopy (SEM), adhesion cross-cut tape (ACCT) test, X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), electrochemistry and immersion test, the results revealed that the corrosion current density (Icorr) of the coatings decreased by approximately four orders of magnitude and had good corrosion resistance. [ABSTRACT FROM AUTHOR]

Magnesium alloy has good application prospects in high-precision industries such as electronics and aerospace due to its low density, high stiffness, and excellent properties. However, the poor corrosion resistance of magnesium alloy limits its wide application. In this study, a corrosion-resistant protective coating of magnesium hydroxide doped with nano-silica was grown in situ on a magnesium alloy substrate by the hydrothermal method. The morphology, composition, structure, and corrosion resistance of the coating were investigated by scanning electron microscopy, FTIR, XRD, and electrochemical processes, respectively. The results showed that the prepared coating had good corrosion resistance, as the corrosion current of the magnesium alloy was reduced by about four orders of magnitude for the bare magnesium alloy substrate. [ABSTRACT FROM AUTHOR]

Nowadays, few works have been undertaken to explore the anti-corrosion coatings with tunable surface colors. In order to further expand the industrial application of magnesium alloy, a facile one-step hydrothermal method was applied to AZ91D magnesium alloy to obtain anti-corrosion coatings with diversified colors. The formation mechanism was discussed, and the corrosion resistance of the coating was assessed by electrochemical tests, immersion tests, and salt spray tests. The results show that different coating colors such as yellow, cyan, blue and red can be obtained by varying the type and concentration of reagents. The adhesion of the coating to the magnesium alloy substrate was great, and the corrosion current density of the sample with the best anti-corrosion effect was reduced by three orders of magnitude. This method has practical significance in promoting the development of surface coloring and industrial applications of magnesium alloys. • Prepared by a simple one-step hydrothermal method, the reagents used are environmentally friendly. • The prepared coating has bright and a wide range of color and the color change is easy to control. • The coating has an excellent adhesion with the substrate. [ABSTRACT FROM AUTHOR]

[Display omitted] • The regular hierarchical micro-nano structures were constructed via one-step etching. • The prepared superhydrophobic surface possesses a CA of 173.3° and a SA below 1°. • The surface prepared within 1h boasts high chemical stability and water resistance. Nowadays, achieving highly effective superhydrophobic surfaces on chemically active magnesium alloys via a straightforward and efficient etching method remains a formidable task. In this study, we have successfully fabricated regular mulriple hierarchical micro-nano structures on AZ91D substrates through a one-step etching process. The resultant nano-chrysanthemums exhibit remarkable biomimicry wherein the extended nanostructures and the protrusions on them further enhance the air–liquid interface contact area. Subsequent to the modification, the contact and sliding angles of the samples achieved exceptional performance surpassing that of previous etching techniques. Furthermore, this low adhesion surface demonstrates commendable chemical stability even when exposed to air, chemically aggressive solutions (including strong acids and bases), and cyclic icing/melting treatments. Moreover, this versatile superhydrophobic surface exhibits exceptional resistance to various forms of contamination. The method employed to generate such advantageous superhydrophobic surfaces necessitates minimal equipment complexity and boasts substantial advantages in terms of affordability and efficiency. These characteristics not only confer promising prospects for widespread application but also render it suitable for large-scale industrial production. [ABSTRACT FROM AUTHOR]

Magnesium alloys have been widely used as a new medical metal implant material because of their good physicochemical properties, biodegradability and biocompatibility. But magnesium alloys are very chemically active and easily corroded after being implanted in the human body. In this paper, a hydroxyapatite/fatty acid salt superhydrophobic composite film was prepared on the surface of magnesium alloys by hydrothermal method. By testing, the water contact angle of the prepared composite film layer reaches 154.5°, and the corrosion current density is reduced by two orders of magnitude, which effectively improves the corrosion resistance of magnesium alloys. The hydrophobic properties of the prepared superhydrophobic composite membrane show good chemical stability. This preparation method can have good application prospects in industry and medical materials because of its simplicity and efficiency. [ABSTRACT FROM AUTHOR]

A one-step in-situ hydrothermal method (HT) was performed on magnesium alloys to prepare Mg(OH) 2 -SiO 2 -Al(OH) 3 (MSA) composite coatings with strong corrosion resistance. In this study, the aluminum-rich Mg(OH) 2 was used as the bottom layer, and SiO 2 -Al(OH) 3 microsphere particles generated by self-assembly of strip monomers were the top layers, which together prevented the penetration of corrosive ions (Cl−) into the AZ91D surface. Due to the in-situ growth process, the adhesion between the film and the substrate stays strong, and the generation of silicate during HT further enhanced the stability of the coating, which improved its potential for practical application. Electrochemical experiments showed that the MSA composite multilayer film strengthened the corrosion resistance of AZ91D, and the corrosion current density decreased by about five orders of magnitude. The connection between particle morphology and different preparation conditions was also discussed. MAS composite coatings provide a new approach to corrosion protection of metal substrates. • The MSA3170 composite coatings with strong corrosion resistance were synthesis by in-situ one step hydrothermal method. • The formation of silicate aids in the interconnection of Mg(OH) 2 and spherical particles. • The formation mechanism and the differences in surface morphology are discussed. [ABSTRACT FROM AUTHOR]

Superhydrophobic surface was obtained on pretreated magnesium alloy substrates via Nano silver deposition and electroless Ni-P plating followed by stearic acid modification. The surface with hierarchical structure had a water contact angle of 157.8° and exhibited excellent superhydrophobicity. The surface morphology of the sample, the chemical compositions and wettability were characterized by scanning electron microscopy (SEM), XRD (X-ray diffraction), Fourier transformed infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. The potential polarization curves revealed the corrosion resistance of superhydrophobic sample was enhanced as the corrosion current density decreased by 2 orders of magnitude. [ABSTRACT FROM AUTHOR]

At present, it is still a challenge to efficiently and environmentally prepare corrosion-resistant coating with good adhesion on magnesium alloy. In this paper, the composite coating of ammonium magnesium carbonate tetrahydrate (AMCT) and calcium carbonate (CC) was prepared on AZ91D magnesium alloy by a simple one-step in-situ growth process. The surface morphology and composition of the samples were characterized. The corrosion resistance of the sample in 3.5 wt%NaCl solution was evaluated, and the electrochemical test results showed that the I corr of the coated samples decreased by 3 orders of magnitude compared with that of the Mg substrate, and the corrosion resistance was significantly improved. In addition, the forming mechanism and adhesion properties of the coating are also discussed. The results show that the ratio of AC/CG in the reaction solution and the reaction time are important factors to determine the coating formation. When the molar ratio of AC/CG is 5:1 and the reaction time is 89 h, the prepared coating has good adhesion to the substrate and the best corrosion resistance. The method does not use expensive drugs and instruments, and does not need complicated pretreatment, so it has great advantages in reducing cost and improving efficiency. • We developed a new method to prepare corrosion-resistant coating on magnesium alloy surface. • The method is efficient and environment-friendly, and expands the application of magnesium alloy anticorrosive coating. • The prepared coating has excellent corrosion protection and good adhesion. [ABSTRACT FROM AUTHOR]

Micro-arc oxidation is a low-cost and environmentally friendly technology for improving the corrosion resistance of magnesium alloys. However, the inherent porous structure limits the application of magnesium alloy micro-arc oxidation coatings in corrosion resistance. Herein, we investigated the corrosion resistance and friction resistance of the magnesium alloy micro-arc oxidation coating after being sealed by hydrothermal treatment and heat treatment. SEM, FTIR, XRD and XPS were performed to investigate the surface morphology and chemical composition of the prepared coating. The potentiodynamic polarization curve and electrochemical impedance spectroscopy confirmed that the prepared sample has good corrosion resistance in 3.5 wt% NaCl aqueous solution. In addition, the samples with coating also exhibit good friction resistance. After friction test, the samples still maintain good corrosion resistance. This method not only promotes the application of magnesium alloys in corrosive environments, but also has great potential for industrial production. • A pore-sealing coating was prepared on the surface of micro-arc oxidized AZ91D magnesium alloy by hydrothermal treatment and heat treatment. • The potentiodynamic polarization curve and EIS confirmed that the prepared sample has excellent corrosion resistance in 3.5 wt% NaCl solution. • After friction test, the corrosion rate of the samples is basically the same as that of the samples without friction. [ABSTRACT FROM AUTHOR]

The application of superhydrophobic materials has been handicapped by complex processes and poor environmental friendliness. Magnesium alloys are widely used in daily production due to their low density and good casting properties. A facile and environmentally friendly method was proposed to prepare a superhydrophobic layer with coral-like microstructure on the surface of AZ91D magnesium alloy by high temperature heating. The prepared superhydrophobic surface has a contact angle of 159.1° and a rolling angle of 4.8°. The corrosion current of superhydrophobic surface has been reduced by about two orders of magnitude relative to the magnesium alloy substrate and its inhibition efficiency is 96.94%, which demonstrates its great corrosion resistance. In addition, the superhydrophobic surface has great thermal stability. When the temperature rises to 190 °C, the contact is still above 150°. Excellent self-cleaning and advantages in preparation efficiency, environmental protection and cost-effectiveness will boost its good application prospects. [ABSTRACT FROM AUTHOR]