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Ethylene glycol solutions can cause severe corrosion in magnesium alloys, leading to safety and stability concerns. The addition of corrosion inhibitors to the environment is a simple and effective protective measure. This study introduces a compound corrosion inhibitor that combines inorganic and organic components, providing resistance to salts, high temperatures, and environmental factors. The corrosion inhibition of AZ91D magnesium alloy using a sodium silicate/triethanolamine compound inhibitor in 50% glycol coolant was investigated through electrochemical analysis, morphology characterization, and weight loss analysis. The results demonstrated that the sodium silicate/triethanolamine inhibitor effectively prevented corrosion of AZ91D magnesium alloy in 50% ethylene glycol, achieving a maximum inhibition efficiency of 96.4% with 2 g/L sodium silicate and 3 mL/L triethanolamine. The inhibitor exhibited continued effectiveness at elevated temperatures and showed minimal impact from external ions, providing strong protection for AZ91D magnesium alloy in glycol coolant. The outstanding performance can be attributed to the synergistic interaction of triethanolamine and sodium silicate, which form a protective film on the alloy’s surface. This compound inhibitor exhibits promising potential for safeguarding AZ91D magnesium alloy in similar environments. Furthermore, the proposed mechanism elucidates how the sodium silicate/triethanolamine mixture mitigates galvanic corrosion in the AZ91D magnesium alloy. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) alloys can be applied in many fields, but their poor corrosion resistance limits their widespread applications. Metal-organic frameworks (MOFs) are often used as fillers in the field of corrosion protection due to their poor adhesion. In order to improve the film-forming performance and adhesion of MOFs coatings, and enhance the corrosion resistance of AZ31 Mg alloys, various MOFs coatings were prepared on the Mg alloy micro-arc oxidation (MAO) coating. The results demonstrated that the MAO facilitated film-forming of MOFs and enhanced their adhesion. Moreover, MOFs crystals can seal the pores of MAO, capture corrosive ions, and form insoluble chelates, significantly improving the corrosion resistance of Mg alloys. Among them, the Ce-MOF exhibited the highest corrosion resistance and the lowest corrosion rate, with a corrosion current density of 8.68 × 10−8 A/cm2 after immersing for 30 min. Moreover, MOFs coatings exhibited good stability and durability, and even after immersing in 3.5 wt% NaCl solution for 14 days, their corrosion protection effects were still superior than MAO. [Display omitted] • Various MOFs coatings were prepared on the Mg alloy MAO coating. • MAO facilitated MOFs film-forming and making them exhibited good adhesion with AZ31. • MOFs crystals can seal the pores of MAO, capture corrosive ions, and form insoluble chelates with the Mg matrix. • Ce-MOF coating exhibited lowest corrosion rate and highest corrosion resistance. [ABSTRACT FROM AUTHOR]

The superhydrophobic composite coating PVB/STA/ZIF-8@SiO 2 has been designed on the surface of AZ31B Mg alloy by using a drop coating method to improve its corrosion resistance. [Display omitted] • The prepared PSZS composite coating showed superhydrophobic (CA＞150°). • The PSZS composite coating exhibited superhydrophobic with wear resistance after 300 cm of friction. • The PSZS composite coating exhibited good corrosion durability after immersing in 3.5 wt% NaCl aqueous environment for 7 days, which can provide long time and effective corrosion protection for Mg alloy. Magnesium (Mg) alloys are susceptible to being attacked by corrosive ions in practical application environments, which limits their widespread application as the most promising engineering material. Herein, the superhydrophobic composite coating PVB/STA/ZIF-8@SiO 2 (PSZS) has been designed on the surface of Mg alloy by using a drop coating method to improve its corrosion resistance. In this study, we provide an approachable decoration strategy for hydrophobic and hierarchical modification of zeolite imidazolate frameworks (ZIF-8) with stearic acid (STA) and SiO 2 , and combined with polyvinyl butyral (PVB) to form a composite coating with excellent performance on the substrate surface. Notably, the PSZS composite coating exhibited superhydrophobic and the contact angle is greater than 150° after 300 cm of mechanical friction. The electrochemical testing of the PSZS composite coating indicated that it greatly protected the Mg alloys from corrosion. Moreover, the PSZS coating displayed highly effective corrosion resistance even after being immersed in 3.5 wt% NaCl aqueous solution for 7 days. Overall, the PSZS composite coating with the advantages of corrosion resistance, corrosion durability, superhydrophobic, abrasion resistance and simple preparation process broadens the horizons of Mg alloy corrosion resistance research. [ABSTRACT FROM AUTHOR]

Magnesium alloys offer an alternative for applications in biodegradable implant devices within human body, eliminating the need for subsequent surgeries to remove metallic parts. Nevertheless, the uniform degradation rate of magnesium (Mg) alloys must be enhanced by applying surface coatings, preferably incorporating bactericidal and biocompatible agents, to improve the implant properties. In this study, magnesium alloys ZK60 (Mg, Zn, and Zr) and ZK60-Mm (Mg, Zn, and Zr with 1.5 % mass of rare-earth elements - mischmetal), both having a specific mass close to the bone, were investigated. The surfaces were coated with ZnO using physical vapor deposition (PVD) in the HiPIMS (High Power Impulse Magnetron Sputtering) mode. The corrosion resistance and degradation of the alloys were studied using electrochemical and immersion tests in simulated body fluid. Surface analysis and microstructures were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and X-ray Diffraction (XRD). The results showed that the ZnO coating favors osseointegration with hydroxyapatite formation after immersion in SBF. Moreover, electrochemical analysis indicates an enhancement in corrosion resistance. On average, the corrosion current density decreases by a factor of four for the ZK60 alloy and two for the ZK60-Mm alloy post-coating. The corrosion rate of ZnO-coated alloys is lower compared to that of uncoated alloys, showcasing the promising utility of this coating. [Display omitted] • Successful HiPIMS ZnO coating of ZK60 and ZK60 alloys with 1.5 % mischmetal. • Corrosion resistance of coatings makes them suitable for use as biomaterials. • Coatings show hydroxyapatite mineralization ability. • ZK60-ZnO coating shows superior corrosion resistance with low current density. [ABSTRACT FROM AUTHOR]

Functionalized carbon materials can act as high-temperature coatings and eco-friendly composite materials. We have studied lanthanum-doped carbon nanotube (La-CNT) material redox behavior, cytotoxicity, and corrosion inhibition efficiency. The La-CNT material has been characterized by different techniques to confirm the presence of functional groups. The Fourier transform infrared (FTIR) and Raman studies were performed to investigate the functional groups and carbon defects. Field emission scanning electron microscopy (FESEM) and tunneling electron microscopy (TEM) studies were used to investigate the carbon nanotube microstructure, La nanoparticles were shown to interact with the carbon nanotube surface. X-ray diffraction (XRD) techniques were used to confirm the crystallinity of composite material. Electrochemical methods were used to investigate corrosion inhibition and redox stabilities. After corrosion study on the Mg alloy its microstructure was analyzed to confirm the composite material inhibition efficiency. The composite material showed significant cytotoxicity, and corrosion inhibition efficiency was shown to be 82 % as compared with pristine epoxy-coated Mg alloy.XPS results are suggested that alloy oxide layer formed. The DFT study supported the experimental findings. The molecular electrostatic potential map of La-CNT (A), Protonated form of La-CNT could trap corrosive ions by physisorption (B). [Display omitted] • Lanthanum nano particles functionalized CNT showed high corrosion resistance 3.5% NaCl • The lanthanum 3+, 2+ cations may controlled aggressive corrosive chlorides ions • Lanthanum nano parctiles acts as a green corrosion additive in near future Lanthanum nanotubes CNT showed excellent cyctotoxicity in cell line [ABSTRACT FROM AUTHOR]

Owing to the unique active corrosion protection characteristic of hexavalent chromium-based systems, they have been projected to be highly effective solutions against the corrosion of many engineering metals. However, hexavalent chromium, rendered a highly toxic and carcinogenic substance, is being phased out of industrial applications. Thus, over the past few years, extensive and concerted efforts have been made to develop environmentally friendly alternative technologies with comparable or better corrosion protection performance to that of hexavalent chromium-based technologies. The introduction of corrosion inhibitors to a coating system on magnesium surface is a cost-effective approach not only for improving the overall corrosion protection performance, but also for imparting active inhibition during the service life of the magnesium part. Therefore, in an attempt to resemble the unique active corrosion protection characteristic of the hexavalent chromium-based systems, the incorporation of inhibitors to barrier coatings on magnesium alloys has been extensively investigated. In Part III of the Review, several types of corrosion inhibitors for magnesium and its alloys are reviewed. A discussion of the state-of-the-art inhibitor systems, such as iron-binding inhibitors and inhibitor mixtures, is presented, and perspective directions of research are outlined, including in silico or computational screening of corrosion inhibitors. Finally, the combination of corrosion inhibitors with other corrosion protection strategies is reviewed. Several reported highly protective coatings with active inhibition capabilities stemming from the on-demand activation of incorporated inhibitors can be considered a promising replacement for hexavalent chromium-based technologies, as long as their deployment is adequately addressed. [ABSTRACT FROM AUTHOR]

rGO/Mg(OH)2 composite films were fabricated on AZ61 alloy by the hydrothermal method in alkaline solutions containing deionized water and graphene oxide (GO). During the hydrothermal reaction, the Mg(OH)2 nanosheets and GO plates grew freely on the AZ61 substrate without any special orientation, and the GO was simultaneously reduced to rGO. With the increase of GO content in the hydrothermal solution, the corrosion resistance of the prepared composite films showed a trend of increasing first and then decreasing. When the content of GO incorporated in the hydrothermal solution is 5 mg, the corrosion current density (icorr) of the composite coating is reduced to the minimum (4.9 μA/cm2), which is seven times lower than that of the substrate and 3.5 times lower than that of the Mg(OH)2 monolayer. Based on experimental and molecular dynamics simulation results, the enhancement mechanism of the composite film was proposed, which is related to the growth of Mg(OH)2 layer, the "tortuous path" effect of GO and the slowing of chloride ion diffusion by GO functional groups. [ABSTRACT FROM AUTHOR]

High-strength Mg-Zn-Y alloy with a long-period stacking ordered (LPSO) phase was chosen as the base alloy, and different Ca were added to it. The phase component and microstructure of the alloys were examined using diffraction of X-rays (XRD) and scanning electron microscopy (SEM). A new phase, Ca2Mg6Zn3, was found to be formed by the addition of Ca. The hydrogen evolution corrosion method and an electrochemical test showed that the amount of hydrogen evolution without Ca addition was twice that with Ca addition. The corrosion resistance of the magnesium alloy improved when the amount of Ca added was. In order to understand the dynamic corrosion process, we soaked Mg97Zn1Y2-X wt-% Ca (X = 0, 0.1, 0.3, 0.6, 1) alloy in 3.5 wt-% NaCl solution for 2, 6, 12 h. It was observed that with an increase in the Ca content, the degree of corrosion of the alloy gradually decreased, and the amount of granular corrosion products covering the alloy's surface also decreased. [ABSTRACT FROM AUTHOR]

• Multifunctional PEO-coatings with active corrosion protection is formed on Mg alloy. • PEO-coating is modified with corrosion inhibitor – 8-hydroxyquinoline (8-HQ). • The polymer treatment of the PEO-layer does not reduce the inhibitor's efficiency. • The mechanism of corrosion degradation of smart composite coating is established. • The antibacterial activity of the coatings against S. aureus strain is proved. A new method of the formation of composite coatings with the function of active corrosion protection of magnesium alloys was developed using the plasma electrolytic oxidation (PEO) method. Susceptibility of PEO-layers to pitting formation was evaluated using localized electrochemical methods (SVET/SIET). The morphological features and electrochemical properties of composite coatings were studied using SEM/EDX, XRD, micro-Raman spectroscopy and EIS/PDP measurements, respectively. The effect of surface layers impregnation with corrosion inhibitor on their protective properties in a corrosive environment was established. Additional protection was achieved using controllable coating pore sealing with polymer. It was found that the polymer treatment of the PEO-layer does not reduce the inhibitor's efficiency. The formed protective composite inhibitor-and-polymer-containing layers decrease the corrosion current density of a magnesium alloy in a 3 wt.% NaCl solution to three orders of magnitude. This predetermines the prospect of new smart coatings formation that significantly expand the field of application of electrochemically active materials. The mechanism of smart composite coating corrosion degradation was established. The antibacterial activity of the inhibitor-containing coatings against S. aureus methicillin-resistant strain was proved using the in vitro model. These protective layers are promising for reducing the incidence of implant-associated infections. [Display omitted] [ABSTRACT FROM AUTHOR]

The rapid degradation characteristics of magnesium alloys limit its application in the field of orthopedic fracture fixation and cardiovascular stents. This study aimed to improve the corrosion resistance and biocompatibility of AZ31 magnesium alloys and prepare degradable implant materials. Micro-arc oxidation (MAO) was used to change the concentration of yttrium acetate in the electrolyte to prepare coatings with different yttrium content on the surface of AZ31 magnesium alloy. Through characterization, it is proved that the yttrium in the coating mainly exists in the form of Y3+. The polarization potential experiment shows that the micro-arc oxidation coating significantly improves the corrosion resistance of magnesium alloys. With the increase of yttrium acetate concentration in the electrolyte, the corrosion resistance of the coating first increases and then weakens. When the concentration is 0.0035 mol/L, the coating has the highest corrosion resistance. The results of CCK-8 cytotoxicity experiment and cell morphology observation also proved that the cell viability in each group was greater than 140%, and the yttrium-doped coating on the surface of AZ31 magnesium alloy has no cytotoxicity, can promote cell growth, and has good biocompatibility. [ABSTRACT FROM AUTHOR]

Clinical applications of bio-absorbable magnesium (Mg) and its alloys can be enhanced by increasing their corrosion resistance, using surface modification and functionality. In this study, we synthesized graphene oxide (GO) through improved Hummers' method and deposited it on biodegradable AZ31B Mg alloy for further characterization. Different suspensions of GO were prepared in various solvents, like deionized water, ethanol, and acetone by ultra-sonication. Electrophoretic deposition (EPD) was used to develop GO coatings on AZ31B Mg using different GO suspensions. Effect of various solvents on corrosion behavior, as well as in vitro biocompatibility, was studied. The optimized EPD parameters were 3 volts and 90 s for coating. Different characterization techniques were used to study GO and prepared coatings. Atomic force microscopy found that the average thickness of GO was ~1 nm. Electrochemical behavior of coatings was studied through electrochemical impedance spectroscopy (EIS) and Tafel analysis in Ringer's lactate solution. Tafel analysis revealed that GO coatings deposited by GO water suspension increased corrosion protection efficiency of AZ31B Mg alloy by ~94%. After 72 h incubation in MC3T3-E1 osteoblast cells extract, in vitro analysis was performed to determine the cell viability and biocompatibility of the GO- coated and bare Mg samples. GO coatings deposited by GO water suspension demonstrated ~2× cell viability, as well as nontoxicity and better biocompatibility compared to the bare and other GO-coated Mg samples. [ABSTRACT FROM AUTHOR]

This work analyzes the Tungsten Inert Gas (TIG)welded joint of AZ31 magnesium alloy and the pitting corrosion stress field at different depths under tensile load via the ANSYS finite element method. The strengths of the stress and strain fields inside the corrosion pit were substantially higher than the average strength level of the matrix. Therefore, under the influence of the applied load, the corrosion pit will fail first. Based on the study of pitting corrosion, a model was developed to explain how pitting corrosion cracks propagate in magnesium alloy welded joints. Finally, the variation of residual strength was revealed to study the corrosion dynamic mechanism of the joints. [ABSTRACT FROM AUTHOR]

In this study, corrosion and stress corrosion behaviors of AZ31, AZ61, and AZ91 magnesium alloys coated with aluminum by the electric arc spray method were investigated in 3.5 wt.% NaCl solution. Structural properties of coated materials were investigated by scanning electron microscopy (SEM), energy dispersive X‐ray analysis, and X‐ray diffraction. Electrochemical properties were determined using the potentiodynamic polarization method in 3.5 wt.% NaCl solution. Potentiodynamic polarization curves showed that corrosion current density values did not change with coating in aluminum‐coated samples by the electric arc spray method. In contrast, corrosion potential value increased toward positive values. Slow strain rate test (SSRT) was used to determine the stress corrosion behavior and stress corrosion indexes (ISCC), ultimate tensile strength (UTS), and elongation of AZ31, AZ61, and AZ91 magnesium (Mg) alloys were determined. As a result of the SSRT, the aluminum coating process decreased significantly the stress corrosion indexes of AZ31, AZ61, and AZ91 Mg alloys. The fracture of surface images was also examined in the SEM, and both intergranular and transgranular stress corrosion cracking were observed in all three alloys. [ABSTRACT FROM AUTHOR]

The study of corrosion of magnesium and its alloys has emerged a hot topic in the applications of lightweight structural materials. The inherently high electrochemical activity of bare magnesium surfaces still lacks a convincing mechanism to describe the observed experimental characteristics, and it has prompted the development of various types of protective coatings with the aim of slowing metal dissolution. In recent years, new instruments and techniques have been developed to study with spatial resolution the local corrosion processes that occur in metallic materials in general, and for magnesium and its alloys in particular, both for bare surfaces and coated. Scanning microelectrochemical techniques, such as local electrochemical impedance spectroscopy (LEIS), scanning electrochemical microscopy (SECM), scanning vibrating electrode technique (SVET), scanning ion-selective electrode technique (SIET) and scanning Kelvin probe (SKP) can provide information about the local electrochemical activity of metallic surfaces. In the present work, the applications of these techniques in corrosion studies of magnesium and its alloys are reviewed. Assessment of corrosion mechanisms, barrier properties of conventional coatings and active corrosion behavior of self-healing coatings are examined. Limitations and future developments in this area are discussed. [ABSTRACT FROM AUTHOR]

Superhydrophobic coating has been widely studied for its great applicational potential, such as for corrosion protection of magnesium alloys while it has been restrained by expensive materials, sophisticated preparation process and infirm rough structures. In this study, the electrochemical method was adopted by using a two-electrode system for rapid hydrophobic modification to obtain superhydrophobic kaolin. By mixing the modified superhydrophobic kaolin with commercial epoxy resin and polydimethylsiloxane glue, a paint can be formed and easily used on various substrates for preparation of superhydrophobic coating via spraying method. The influence factors on wettability of the modified kaolin and the mixing ratio of each component of the coating were explored. Also, the wettability, durability and anticorrosion of the prepared coating were evaluated comprehensively. The coating was able to maintain superhydrophobic after immersed in HCl solution at pH 1, the NaOH solution at pH 14, and 3.5 wt.% NaCl solution for 16, 21, 30 days, respectively. In addition, the coating exhibited 4A grade adhesion, high hydrophobicity after abraded for 200 cycles on a 600-mesh sandpaper with 100 g weight, and 99.86% anticorrosion efficiency after soaked in 3.5 wt.% NaCl solution for 20 days, demonstrating a good robustness and anti-corrosion property. Furthermore, the coating showed good transparency, flexibility and was easy to make in a large scale by the spraying method, which is of great significance to promote the practical application of superhydrophobic coatings and the anticorrosion Mg alloys. [Display omitted] [ABSTRACT FROM AUTHOR]

Corrosion behavior of AZ31 magnesium alloy in NH 4 +-bearing chloride solution with controlled pH was investigated by weight loss experiment, hydrogen collection, and electrochemical test combined with surface morphology and topography observation. The results show that NH 4 + and pH of the solution can affect the corrosion of AZ31 magnesium alloy. The existence of NH 4 + affects the formation and dissolution of corrosion products, which makes the protective effect of the corrosion product layer weaker. The change of pH value not only affects the corrosion mechanism of AZ31, but also alters the concentration of NH 4 + ions in the solution, which further influences the corrosion product layer of AZ31, and finally makes the corrosion of AZ31 change significantly. [ABSTRACT FROM AUTHOR]

Nowadays, there is a great demand for increasing the strength and corrosion resistance of magnesium alloys for their wider use in machine engineering, oil industry, and medicine. This paper is devoted to a study on the effects of the combined process of reduction and equal channel angular pressing, as well as the subsequent ultrasonic irradiation on the structure, strength, and corrosion properties of the Mg-Al-Zn alloy. Deformation processing results in an increase of the strength up to 280 ± 10 MPa. A fine-grained structure is formed with a grain size of 10–20 µm and small recrystallized grains 1–2 µm in size. The corrosion resistance in the HCl medium falls down significantly. Action of ultrasound on the deformed specimen leads to an increased fraction of high-angle boundaries, in particular, the fractions of special, fully overlapping Σ13a boundaries and twin boundaries of Σ15b and Σ17a systems. Due to the ultrasonic treatment, the strength of the Mg-Al-Zn alloy increases up to 310 ± 5 MPa, while the corrosion resistance in HCl almost doubles. [ABSTRACT FROM AUTHOR]

Chamberprotection of metals from atmospheric corrosion is a variety of vapor-phase inhibition. It is based on the effect of adsorption films formed in the vapors of low-volatile corrosion inhibitors at elevated temperatures. The paper analyzes the specific features of the chamber protection of a magnesium alloy with chlorobenzotriazole. It has been found that the protective properties of surface films formed in hot vapors of this compound increase upon exposure of the metal to air. The processes of structuring of protective films that occur in this case have been studied by a set of corrosion, electrochemical and physical methods. It has been shown that chamber treatment of the alloy is accompanied by chlorobenzotriazole adsorption and uniform thickening of the surface oxide-hydroxide layer. In this case, the corrosion processes slow down by a factor of up to 10. Prolonged exposure of the samples in air after the chamber treatment results in additional oxidation of magnesium and hydroxylation of the oxide. However, the oxide-hydroxide layer does not grow on the entire surface, but as separate islets. Such a change in the structure of the surface films results in an additional 10-fold increase in the corrosion resistance of the magnesium alloy. [ABSTRACT FROM AUTHOR]

This study aims to prepare hydroxide films on the surface of ZK60 magnesium alloy to improve the corrosion resistance of the latter. The hydroxide films were fabricated with a facile hydrothermal method using Mg(NO3)2 and Mn(NO3)2 aqueous solutions. The treatment temperature was maintained at 353 K, while the treatment time was 6 h, 12 h, and 24 h. X-ray diffraction (XRD) and Fourier transform-infrared (FT-IR) spectroscopy demonstrated that the films were composed of a mixture of Mg(OH)2 and Mn(OH)2. As revealed by scanning electron microscopy (SEM), each film grew from an incomplete lamellar structure to a thick lamellar structure at changing treatment times. The corrosion current density of the 12 h film sample immersed in a simulated body fluid (SBF) reached 3.07 × 10−7 A·cm−2, which was approximately two orders of magnitude lower than that of the ZK60 magnesium alloy substrate (3.04 × 10−5 A·cm−2). In addition, the hydrogen evolution experiment showed that, even after 168 h of immersion, the 12 h film sample could still provide protection for the substrate. [ABSTRACT FROM AUTHOR]

Graphene and its derivatives have attracted much interest as corrosion-resistant coatings for magnesium alloys since 2014, when the first reports appeared in the literature. The interest in the use of such carbonaceous compounds to protect magnesium and its alloys from corrosion relies on a set of attributes such as chemical inertness, and high surface area. To support the development of optimized graphene-based films it is imperative to expand the current knowledge toward a deeper understanding of corrosion mechanisms and their interaction with practical aspects related to coating deposition and morphology. In the present work, graphene-based coatings for magnesium alloys are reviewed. We explored the correlation between coating architecture, deposition methods and materials selection using the Ashby approach. The results of the materials selection process revealed that composite coatings consisting of an inorganic matrix obtained by plasma electrolytic oxidation of magnesium alloys and graphene oxide nanosheets as blocking agents can provide surfaces with high corrosion resistance in sodium chloride solution. For biomedical applications, composite coatings consisting of a mixture of organic matrices such as chitosan and graphene oxide as reinforcing particles are attractive candidates. The results are discussed based on coating architecture and its interplay with the corrosion properties. [ABSTRACT FROM AUTHOR]

The corrosion resistance of magnesium alloys can be effectively improved by surface treatment. In this study, a hydrophobic two-dimensional (2D) TiO2/MoS2 nanocomposite coating was fabricated on AZ31B magnesium alloy by an electrophoretic deposition method. The corrosion resistance of the coating was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy analyses. After being modified by a silane coupling agent (KH570), the TiO2/MoS2 coating changed from hydrophilic to hydrophobic, and the static water contact angle increased to 131.53°. The corrosion experiment results indicated that the hydrophobic 2D TiO2/MoS2 coating had excellent anticorrosion performance (corrosion potential: Ecorr = −0.85 VAg/AgCl, and corrosion current density: Icorr = 6.73 × 10−8 A·cm−2). TiO2/MoS2 films have promising applications in magnesium alloy corrosion protection. [ABSTRACT FROM AUTHOR]

Fluorinated hydroxyapatite-titanium dioxide coating (F-doped HA-TiO2) was deposited in situ onto AZ31 Mg alloy using electrodeposition method. XRD and EDS confirmed the crystal structure and composition of the coating. SEM images showed that the F-doped HA-TiO2 coating on the surface of AZ31 Mg alloy was extremely uniform and the thickness of coating was reflected by the cross-sectional image. Corrosion behavior of the coating modified Mg alloy was tested by electrochemical and immersion experiments. Compared to the corrosion current density (Icorr) of the uncoated AZ31 Mg alloy in Hank's solution, the Icorr of F-doped HA-TiO2 coating was decreased almost 4 orders. The coated AZ31 Mg alloy showed superior biocompatibility, which was strongly demonstrated by the amounts of cells increased in cell culture. The results of hemolysis tests also illustrated that the F-doped HA-TiO2 coating met the requirements of biomedical materials. [ABSTRACT FROM AUTHOR]

Due to lattice reorientation, grain segmentation, induced recrystallization, twins play a very important role in regulating texture, refining grains, improving mechanical properties and corrosion resistance, and has received more extensive attention. Numerous studies have shown that {10-12}<10-11> tensile twins (TTWs) are easily activated in large quantities due to the lower critical resolve shear stresses (CRSS). Introduction of TTWs under uniaxial compression improved the strength, ductility, and formability of magnesium (Mg) alloys. Moreover, TTWs produced by multi-directional impact forging (MDIF) can optimize the microstructure by dividing grains and promoting recrystallization, resulting in significant improvement of mechanical properties. Although {10-11}<10-12> compressive twins (CTWs) and {10-11}-{10-12} double twins (DTWs) can promote dynamic recrystallization (DRX), they are also favorable nucleation sites for cracks. In addition, the type and volume fraction of twins can affect the corrosion resistance, and they also play different roles in the corrosion process of different Mg alloys. Twins have shown great potential for improving structure and properties, but a comprehensive and critical discussion of twins in Mg alloys is still lacking. Therefore, based on previous studies, this article reviews the common types and variants of twins in Mg alloys, influencing factors, and their effects on the microstructure, mechanical properties and corrosion resistance. In addition, some interesting ideas are being proposed for further research. [ABSTRACT FROM AUTHOR]

Magnesium alloys are regarded as potential candidates in industrial and biomedical applications because of their excellent mechanical properties and biodegradability. However, the excessive degradation rate of magnesium alloys can cause a premature disintegration of mechanical integrity, which is the main bottleneck that limits applications. Inspired by nature, various novel surface designs provide a clever strategy to regulate the corrosion behavior of magnesium alloys. This review extensively discusses bioinspired surface designs to reduce corrosion resistance and realize functionalization, so as to offer new ideas with great potential for biomedical applications. Future research on corrosion resistance is expected to benefit greatly from the bioinspired surface designs. [ABSTRACT FROM AUTHOR]

Magnesium-Zinc-Zirconium (Mg-Zn-Zr) alloys have caught considerable attention in medical applications where biodegradability is critical. The combination of their good biocompatibility, improved strength, and low cytotoxicity makes them great candidates for medical implants. This research investigation is focused on providing further insight into the effects of equal channel angular processing (ECAP) on the corrosion behavior, microstructure evolution, and mechanical properties of a biodegradable ZK30 alloy. Billets of Mg-3Zn-0.6 Zr (ZK30) alloy were processed through ECAP up to 4 passes of route Bc (rotating the billets 90° in the same direction between the subsequent passes) at 250 °C. Electron back-scatter diffraction (EBSD) was utilized to investigate the microstructural evolution as well as the crystallographic texture. Several electrochemical measurements were carried out on both a simulated body fluid and a 3.5% sodium chloride (NaCl) solution. Mechanical properties such as Vicker's hardness and tensile properties were also assessed. The as-annealed (AA) microstructure was dominated by equiaxed coarse recrystallized grains with an average grain size of 26.69 µm. After processing, a geometric grain subdivision took place due to the severe plastic deformation. Processed samples were characterized by grain refinement and high density of substructures. The 4-passes sample experienced a reduction in the grain size by 92.8% compared with its AA counterpart. The fraction of high-angle grain boundaries increased significantly after 4-passes compared to the 1-pass processed sample. With regards to the crystallographic texture, the AA condition had its {0001} basal planes mostly oriented parallel to the transversal direction. On the other hand, ECAP processing resulted in crystallographic texture changes, such as the shifting of the ZK30 shear plane to be aligned at 45° relative to the extrusion direction (ED). Furthermore, the maximum texture intensity was reduced from 14 times random (AA billets) to 8 times random after ECAP processing through 4-passes. The corrosion rate of the 4-passes sample was tremendously reduced by 99% and 45.25% compared with its AA counterpart in the simulated body fluid and the NaCl solution, respectively. The pitting corrosion resistance of ZK30 showed notable improvements in the simulated body fluid by 471.66% and 352% during processing through 1-pass and 4-passes, respectively, compared with the 3.5% NaCl findings. Finally, significant improvements in the tensile strength, hardness, and ductility were also achieved. [ABSTRACT FROM AUTHOR]

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• A multifunctional coating was constructed on ZE21B alloy for biodegradable vascular stents. • MgF 2 layer and hydrophilic polymers in the functional coating could effectively protect ZE21B alloy from overfast degradation. • Anticoagulant ACH 11 peptides and ECs-selective REDV peptides in the functional coating could dramatically enhance the hemocompatibility and pro-endothelialization capacity of ZE21B alloy. • The functional coating systematically improved the corrosion resistance and biocompatibility of ZE21B alloy in vitro and in vivo. Biodegradable magnesium alloy stents (MAS) have great potential in the treatment of cardiovascular diseases. However, too fast degradation and the poor biocompatibility are still two key problems for the clinical utility of MAS. In the present work, a functional coating composed of hydrophilic polymers and bioactive peptides was constructed on magnesium alloy to improve its corrosion resistance and biocompatibility in vitro and in vivo. Mg-Zn-Y-Nd (ZE21B) alloy modified with the functional coating exhibited moderate surface hydrophilicity and enhanced corrosion resistance. The favourable hemocompatibility of ZE21B alloy with the functional coating was confirmed by the in vitro blood experiments. Moreover, the modified ZE21B alloy could selectively promote the adhesion, proliferation, and migration of endothelial cells (ECs), but suppress these behaviors of smooth muscle cells (SMCs). Furthermore, the modified ZE21B alloy wires could alleviate intimal hyperplasia, enhance corrosion resistance and re-endothelialization in vivo transplantation experiment. These results collectively demonstrated that the functional coating improved the corrosion resistance and biocompatibility of ZE21B alloy. This functional coating provides new insight into the design and development of novel biodegradable stents for biomedical engineering. [ABSTRACT FROM AUTHOR]

The use of the magnesium alloy AZ31 is common in aviation and biomedicine; however, this alloy has poor friction and corrosion resistance. Here, mechanical grinding, ultrasonic rolling, and ultrasonic rolling + ion implantation were performed on the magnesium alloy surface to study the effect of the treatment process on the friction and corrosion resistance of the magnesium alloy surface. The results show that the surface roughness of the magnesium alloy treated by ultrasonic rolling + ion injection is reduced more than mechanical grinding and ultrasonic rolling. The friction coefficient is the lowest, the wear resistance is the best, and new phase nitrogen compounds appear on the surface. The results of SBF (simulated body fluid) solution immersion showed that the sample treated via this composite process had the lowest corrosion rate, which was 62.45% and 58.47% lower than that of the mechanically ground samples. The surface was relatively intact after the corrosion test, and the corrosion resistance was the best. These results can provide a new strategy for magnesium alloy surface protection. [ABSTRACT FROM AUTHOR]

• A novel maleic hydrazide derivative has been successfully synthesized and characterized, which can provide effective protection for AZ31 magnesium alloy in 3.5 % NaCl. • The complexes formed by the derivative molecules with Mg2+, together with the deposited Mg(OH) 2 , form protective barriers at the interface. • Adsorption involves both electrostatic attraction and electron donation/acceptance and fits the Langmuir isotherm. • The N atoms of the hydrazide group and the adjacent O atoms are the main reaction sites for adsorption. A novel maleic hydrazide derivative containing multiple active groups (NOMAM) has been synthetized and characterized. Electrochemical tests revealed that it can provide effective protection for AZ31 magnesium alloys in 3.5 % NaCl. The best inhibition was achieved at 0.2 g·L−1. The observation results of the surface morphology also confirmed its excellent corrosion inhibition performance. Density functional theory (DFT) calculations and molecular dynamics simulations (MDS) revealed that maleic hydrazide derivative molecules adsorb onto magnesium alloy surfaces via a combination of physisorption and chemisorption with heteroatoms as active sites. The complexes formed by derivative molecules with Mg2+, together with the deposited Mg(OH) 2 , form protective barriers at the interface. The synthesized derivative has many advantages, such as low cost, simple processing and low toxicity. This study can contribute to the search for green corrosion inhibitors for magnesium alloys. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • ZIF-8@PDA smart nanocapsules, 250–350 nm in size, were fabricated. • The nanocapsules in epoxy resin enhanced anti-corrosion and self-healing properties. • Incorporating 1.0 wt% nanocapsules showed the optimal comprehensive properties. This study lies in the first-time incorporation of polydopamine (PDA)-modified zeolitic imidazolate framework-8 (ZIF-8) smart nanocapsules (ZIF-8@PDA) with epoxy resin, systematically improving the comprehensive performance of magnesium alloy coatings and proposing a novel anti-corrosion mechanism based on physical barrier and dual self-healing characteristics. The PDA coating formed on the ZIF-8 surface creates a uniform, dense, and relatively impermeable barrier layer, which enhances the stability of ZIF-8 within the coating matrix. Electrochemical impedance spectroscopy (EIS) tests demonstrate that while the overall electrochemical impedance of the pure epoxy coating decreases, the ZIF-8@PDA 1.0wt% /EP coating exhibits a significant increase in impedance between 10–12 h after being scratched, indicating remarkable self-healing capabilities. After 50 days of immersion in a 3.5 % NaCl solution, the low-frequency impedance value (|Z| 0.01 Hz) of the pure epoxy coating rapidly declines to 0.15 MΩ·cm2, whereas the ZIF-8@PDA 1.0wt% /EP sample shows a much smaller decrease, maintaining an impedance of 50 MΩ·cm2, and the charge transfer resistance (R ct) of the ZIF-8@PDA 1.0wt% /EP coating is three orders of magnitude higher than that of pure EP coating, underscoring the exceptional corrosion inhibition performance. This study introduces a groundbreaking approach to developing smart epoxy coatings with superior corrosion resistance for magnesium alloys. [ABSTRACT FROM AUTHOR]

Medical magnesium-based alloys have great potential in the development of new-generation biodegradable intravascular stents, however, the inferior in vivo corrosion resistance and poor biocompatibility usually cause early loss of mechanical properties, as well as complications such as thrombosis and excessive intimal hyperplasia, severely retarding their clinical applications. To address these issues, we constructed a bioactive coating on the magnesium-based alloy surface that can augment anticorrosion properties and improve biocompatibility through the released NO and CO on the surface. This coating could significantly enhance the surface hydrophilicity of magnesium alloys and endow them with the ability to promote albumin adsorption selectively. The results of electrochemical corrosion and degradation behaviors showed that the bioactive coating could significantly improve the thermodynamic stability of the pristine magnesium alloy and reduce the corrosion rate, thereby significantly enhancing the anticorrosion. Due to the excellent corrosion resistance and surface bioactivities, as well as the introduction of bioactive substances (including heparin, chitosan, etc.), this coating could significantly heighten the hemocompatibility and promote endothelial cell (EC) growth on the surface. Meanwhile, our results demonstrated that under the circumstance of the catalytic release of NO and CO, the anticoagulant and EC growth were significantly enhanced compared to the uncatalyzed state. With the increase of CO-releasing molecules in the coating, the biocompatibility was improved significantly, proving that the released CO can synergistically enhance the biocompatibility with NO. Therefore, the strategy of preparing bioactive coatings that can release NO/CO gases in the present study lays the foundation for the development of magnesium alloy stents with synergistic improvement of biocompatibility. [Display omitted] • A bioactive coating that can catalytically release NO and CO was constructed on the Mg surface. • The NO/CO-gases releasing coating can simultaneously improve corrosion resistance and biocompatibility of magnesium alloy. • Both the catalytic release of NO and CO can enhance the anticoagulant and EC growth. • The released CO can synergistically enhance the biocompatibility of magnesium alloy with NO. [ABSTRACT FROM AUTHOR]

Dilute Mg–Al–Mn–Ca–Gd alloy with extraordinary corrosion resistance (P H = 0.21 mm/year) comparable to that of high-purity Mg was prepared. The Gd addition promoted the second phase transformation from the Al–Mn phase to the Al 8 Mn 4 Gd and Al 2 Gd phases with decreased potential difference with Mg matrix, thus weakening the micro-galvanic corrosion. The homogeneous distribution of nano-sized second phases effectively inhibited localised corrosion, contributing to the integrity of surface film. Furthermore, Gd alloying promoted the formation of compact corrosion products mixed with Gd 2 O 3 and embedded with the nano-sized Al 2 Gd phase, resulting in a stable and protective surface film. [Display omitted] • Dilute Mg alloy with corrosion resistance comparable to high-purity Mg is prepared. • Gd promotes the transformation of Al-Mn phase to less noble Al 8 Mn 4 Gd and Al 2 Gd phase. • The uniform distribution of dense nano-sized phase inhibits localised corrosion. • The surface film containing Gd 2 O 3 and nano-sized Al 2 Gd is more protective to matrix. [ABSTRACT FROM AUTHOR]

• Laser treatment can modulate the morphology, thickness and density of HA coating. • Microstructures and thin oxide layers promote nucleation and deposition of HA. • Adhesion strength of HA coating to Mg alloy substrate is 31.86 ± 1.71 MPa. • Coating effectively reduces the corrosion rate of magnesium alloys to 0.146 mm/y. • Coating with good biological activity can promotes osteoblasts proliferation. Magnesium and its alloys have attracted attention as medical bone implant materials due to their excellent biocompatibility, bone-like mechanical properties, and degradability. However, the clinical application of magnesium is limited by the fact that it corrodes too quickly in body fluids, leading to premature mechanical failure. Surface hydroxyapatite coatings can significantly reduce the initial corrosion of magnesium alloys, but suffer from the problems of non-dense coatings, many defects and poor adhesion strength to the substrate. In this study, we propose femtosecond laser construction of microemulsion cone structures on the surface of magnesium alloys to significantly enhance the densities and thicknesses of the coatings, as well as to improve the bonding strength of the coatings to the substrate, which ultimately reduces the corrosion rate. The corrosion rate of modified hydroxyapatite coating in simulated body fluid is only 0.146 mm/y, and it has the ability to rapidly induce hydroxyapatite mineralization and promote osteoblast proliferation. Furthermore, the surface morphology, chemical composition, and wettability of the laser-modified Mg alloy were analyzed. It was demonstrated that the microstructure and thin oxide layer formed on the surface of the magnesium alloy could provide more sites for HA nucleation, which promotes the deposition and growth of HA and the existence of a mechanical interlocking effect with the substrate. The application of femtosecond laser surface modification represents a rapid and efficacious approach to enhance the quality of hydroxyapatite coatings. This method has successfully controlled the corrosion rate of magnesium alloys with excellent biocompatibility, thereby overcoming potential obstacles to the use of magnesium alloys in clinical applications. [ABSTRACT FROM AUTHOR]

In this study, biodegradable magnesium alloys were produced using the high pressure die casting (HPDC) technique. Effects of Y addition on microstructure, mechanical properties and corrosion behaviors of as-cast Mg–4Sn–xY (x = 0, 1, 2, 4 wt.%) alloys are investigated. The surface morphology of the alloys was examined using field emission scanning electron microscopy (FE-SEM) and the microstructure was examined using energy dispersive spectroscopy (EDS), respectively. Tensile and hardness tests were carried out to examine the mechanical properties. Microstructural studies have shown that the addition of yttrium causes a reduction in the grain size of the alloy and the formation of Sn3Y5 and MgSnY intermetallic compounds with high melting temperature, as well as Mg2Sn intermetallic. While, the maximum tensile strength value is achieved with the addition of 1% yttrium by weight, the increase in yield strength, elongation percentage and hardness values continue with the addition of more yttrium. Corrosion tests have shown that the addition of yttrium to the Mg–Sn alloy increases the corrosion resistance of the alloys due to microstructural changes. The Mg–4Sn–4Y alloy is found to be a promising biodegradable magnesium alloy especially for orthopedic applications. [ABSTRACT FROM AUTHOR]

Superhydrophobic conversion coatings have attracted increasing attention in corrosion protection field due to their exceptional water-repellent properties. However, the retention of protective properties with surface wettability dynamics remains a significant challenge. Herein, a superhydrophobic coupling cerium coating with hierarchical structure is fabricated via cerium-doped deep eutectic solvent pretreatment and modification to extend corrosion resistance duration. The synergistic enhancement between hydrophobicity and active protection can significantly improve the anti-corrosion characteristics of magnesium alloys, resulting in a decrease in corrosion current density by an order of magnitude. The superhydrophobic surface can prevent the metal from corrosive media by reducing the contact area and thus slow down the corrosion rate. The cerium compound within the coating can form a cerium protective layer during the corrosion reaction of magnesium alloy, inhibiting the further corrosion process. Furthermore, the density functional theory (DFT) calculation revealed the corrosion protection mechanism of superhydrophobic coatings. Combining experimental investigations with theoretical calculations, this work provides a new strategy for enhanced anti-corrosion protection of superhydrophobic coatings. • A novel superhydrophobic coupling cerium conversion coating was designed by combining the cerium hierarchical structure with the superhydrophobic surface. • The cerium hierarchical structure was prepared cerium-doped deep eutectic solvent pretreatment. • The coating consists of an active protective primer and a superhydrophobic topcoat. • The corrosion mechanisms are explained through experimental studies, analytical insights, and DFT calculations. [ABSTRACT FROM AUTHOR]

Magnesium alloy is a potential biodegradable metallic material characterized by bone-like elastic modulus, which has great application prospects in medical, automotive, and aerospace industries owing to its bone-like elastic modulus, biocompatibility, and lightweight properties. However, the rapid corrosion rates of magnesium alloys seriously limit their applications. This study collected magnesium alloys' corrosion data and developed a model to predict the corrosion potential, based on the chemical composition of magnesium alloys. We compared four machine learning algorithms: random forest (RF), multiple linear regression (MLR), support vector machine regression (SVR), and extreme gradient boosting (XGBoost). The RF algorithm offered the most accurate predictions than the other three machine learning algorithms. The input effects on corrosion potential have been investigated. Moreover, we used feature creation (transforming chemical component characteristics into atomic and physical characteristics) so that the input characteristics were not limited to specific chemical compositions. From this result, the model's application range was widened, and machine learning was used to verify the accuracy and feasibility of predicting corrosion of magnesium alloys. [ABSTRACT FROM AUTHOR]

Magnesium alloys show broad application prospects as biodegradable implanting materials due to their good biocompatibility, mechanical compatibility, and degradability. However, the influence mechanism of microstructure evolution during forming on the mechanical properties and corrosion resistance of the magnesium alloy process is not clear. Here, the effects of rolling deformation, such as cold rolling, warm rolling, and hot rolling, on the microstructure, mechanical properties, and corrosion resistance of the WE43 magnesium alloy were systematically studied. After rolling treatment, the grains of the alloy were significantly refined. Moreover, the crystal plane texture strength and basal plane density decreased first and then increased with the increase in rolling temperature. Compared with the as-cast alloy, the strength of the alloy after rolling was significantly improved. Among them, the warm-rolled alloy exhibited the best mechanical properties, with a tensile strength of 346.7 MPa and an elongation of 8.9%. The electrochemical experiments and immersion test showed that the hot working process can greatly improve the corrosion resistance of the WE43 alloy. The hot-rolled alloy had the best corrosion resistance, and its corrosion resistance rate was 0.1556 ± 0.18 mm/year. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) and its alloys, which have good mechanical properties and damping capacities, are considered as potential candidate materials in the industrial field. Nevertheless, fast corrosion is the main obstacle that seriously hinders its wide applications. Surface modification is an available method to avoid the contact between corrosive media and Mg substrates, thus extending the service life of Mg-based materials. Generally, manufacturing a dense and stable coating as physical barriers can effectively inhibit the corrosion of Mg substrates; however, in some complex service environments, physical barrier coating only may not satisfy the long-term service of Mg alloys. In this case, it is very important to endow the coating with suitable functional characteristics, such as superhydrophobic and self-healing properties. In this review, the various surface treatments reported are presented first, followed by the methods employed for developing superhydrophobic surfaces with micro/nanostructuring, and an overview of the various advanced self-healing coatings, devolved on Mg alloys in the past decade, is further summarized. The corresponding preparation strategies and protection mechanisms of functional coatings are further discussed. A potential research direction is also briefly proposed to help guide functional strategies and inspire further innovations. It is hoped that the summary of this paper will be helpful to the surface modification of Mg alloys and promote the further development of this emerging research field. [ABSTRACT FROM AUTHOR]

Magnesium alloy, as an absorbable and implantable biomaterial, has been greatly developed in the application field of biomaterials in recent years due to its excellent biocompatibility and biomechanics. However, due to the poor corrosion resistance of magnesium alloy in the physiological environment, the degradation rate will be unbalanced, which seriously affects the clinical use. There are two main ways to improve the corrosion resistance of magnesium alloy: one is by adding alloying elements, the other is by surface modification technology. Compared with adding alloy elements, the surface coating modification has the following advantages: (1) The surface coating modification is carried out without changing the matrix elements of magnesium alloy, avoiding the introduction of other elements; (2) The corrosion resistance of magnesium alloy can be improved by relatively simple physical, chemical, or electrochemical improvement. From the perspective of corrosion resistance and biocompatibility of biomedical magnesium alloy materials, this paper summarizes the application and characteristics of six different surface coating modifications in the biomedical magnesium alloy field, including chemical conversion method, micro-arc oxidation method, sol-gel method, electrophoretic deposition, hydrothermal method, and thermal spraying method. In the last section, it looks forward to the development prospect of surface coating modification and points out that preparing modified coatings on the implant surface combined with various modification post-treatment technologies is the main direction to improve biocompatibility and realize clinical functionalization. [ABSTRACT FROM AUTHOR]

To study the abnormal failure of magnesium anodes for buried pipelines in marine engineering in the unique environment of mudflats, a strain of a sulfate–reducing prokaryote (SRP) was isolated from pipe–laying soil, and identified as Desulfovibrio sp. HQM3. Weight–loss test, electrochemical measurements, SEM, EDS, XRD, and CLSM techniques were used to study the effect of corrosion on the AZ31B magnesium alloy. Under the influence of SRP, the magnesium alloy corroded severely at rates up to 1.31 mm/year in the mudflat environment. SRP accelerated corrosion by 0.3mm/year. Pitting occurred on the samples in both abiotic and biotic systems. The pitting depth reached 163.47 μm in the biotic system after 14 days. The main composition of a petal–like corrosion product was Mg(OH)2. The results show that a mudflat environment can lead to an accelerated corrosion of magnesium alloys. [ABSTRACT FROM AUTHOR]

In order to increase the corrosion resistance of magnesium alloy AZ91 in corrosion environments containing chlorides, the alloy surface has been modified by plasma electrolytic oxidation (PEO). The chemical composition of electrolyte in the PEO process consisted of 12 g/L Na3PO4·12 H2O and 1 g/L KOH, and a direct current was applied to the sample. The corrosion resistance of PEO coating and as-cast AZ91 (sample without PEO coating) was assessed using two different electrochemical methods: electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation (PDP) in 0.1 M NaCl at laboratory temperature. In addition to the electrochemical methods, the morphology of the oxidic coating was observed in the cross-sectional and top surface view by using the SEM technique. For better determination of the microstructure and PEO coating, chemical composition EDX analysis was used. The results of the experiments show that the formation of the PEO coating on AZ91 alloy has a more positive effect on the corrosion resistance in 0.1 M NaCl based on electrochemical methods than in the case of the formed coating on AZ31 alloy from the previous study. Based on electrochemical measurements in the selected environment, the formation of PEO coating on AZ91 was accompanied by a significant increase in polarisation resistance after short-term exposure compared to the as-cast surface. The EIS results showed a 73 times higher Rp value for PEO coated AZ91 when compared to the as-cast AZ91. Correspondingly, a 27 times lower icorr value was observed for PEO coated AZ91 than in the case of substrate AZ91 in 0.1 M NaCl. At the same time, the typically porous and inhomogeneous structure of the formed PEO coating on the magnesium alloy AZ91 was demonstrated. [ABSTRACT FROM AUTHOR]

The corrosion behavior of EW75 magnesium alloy in the Research Vessel KEXUE (RV KEXUE) during the ocean voyage was researched. The weight loss, corrosion depths, corrosion morphologies, and corrosion products were all analyzed. The mean weight loss rate of EW75 alloy Extrusion Surface was 0.0672 mg cm−2 y−1 (0.0903 mm y−1) after exposure corrosion tests, whereas that of Cross-section Surface was 0.0938 mg cm−2 y−1 (0.1537 mm y−1). Both extrusion direction and transverse direction of magnesium alloy samples occurred the brittle fracture in the harsh marine environment, and the mechanical strength fell precipitously after the exposure tests. The corrosion resistance of EW75 magnesium alloys obviously showed the anisotropy, which was due to the texture of the magnesium alloy in the microstructure. High salinity and high humidity environment led to a severe corrosion of EW75 magnesium alloys during exposure in the RV KEXUE during the ocean voyage. This study will provide the effective data for the service of magnesium alloys in typical marine atmospheric environment. [ABSTRACT FROM AUTHOR]

To enhance the mechanical properties and poor corrosion resistance of magnesium alloy in vitro, the as‐cast Mg–2Zn–0.5Zr–1.5Dy (mass%) magnesium alloy was subjected to two types of extrusion treatment, one is hot extrusion (denoted as ET alloy), the other is heat treatment followed by hot extrusion (denoted as HE alloy). The microstructure, mechanical properties, and corrosion behaviors of these extruded alloys are assessed. The results show that the HE alloy has superior mechanical properties and a slower corrosion rate than the ET alloy. The yield strength and elongation of the HE alloy reach 287 ± 10 MPa and 17.6 ± 0.5%, respectively, and its corrosion rate is only 0.59 ± 0.16 mm year−1. After hot extrusion, microscale and nanoscale second‐phase exist in the extruded alloys, and the nanoscale second‐phase can improve their mechanical properties by second‐phase strengthening. However, the presence of microscale second phase can cause galvanic corrosion and result in poor corrosion resistance. The HE alloy has good properties due to it containing more nanoscale second‐phase and fewer microscale second‐phase. [ABSTRACT FROM AUTHOR]

Metallic biomaterials have been widely used in the field of medical implants for replacement purposes and/or for regeneration of tissue. Metals such as stainless steel (316 L), cobalt-chromium alloys and titanium alloys (Ti-6Al-4 V) are widely used as metallic implants today. However, they often exhibit unsatisfactory results such as stress shielding, the release of toxic ions and are often permanent and invasive – where a second surgery is required to remove the implant once the bone is fully healed. Magnesium as a biomaterial have attracted much attention recently due to its excellent biocompatibility, similar mechanical properties to bone and biodegradability. Unlike other metals and bio ceramics, the ability for magnesium alloys to undergo biodegradation eliminates the requirement for a second surgery to remove the implant. Additionally, the degradation of magnesium releases Mg2+ ions, which stimulates metabolism as they are a cofactor in numerous numbers of enzymes. Despite the advantages of magnesium alloys, the rapid degradation of magnesium proved to be challenging as the implant is unable to retain its structural integrity sufficiently enough to act as an implant. To improve the corrosion resistance of magnesium alloys, researchers have been working on the synthesis and characterization of Mg-based bulk metallic glasses, which can significantly improve the corrosion resistance of Mg-based alloys. This paper is a comprehensive review that compiles, analyzes and critically discusses the recent literature on the latest understanding of the processing, mechanical and biological characteristics of Mg-based bulk metallic glasses. [ABSTRACT FROM AUTHOR]

The rapid degradation of Mg alloy was reduced by incorporating titanate on a fluorine-based anodized layer. The coating shows (i) excellent biomineralization ability, (ii) improved local and periodical corrosion behavior and (iii) enhanced expression of osteogenic factors (Runx2, Col 1, OCN and OPN) along with (iv) the antibacterial property. The fluoride and magnesium ions dissolution from the anodized layer is responsible for the better expression of osteogenic factors and antibacterial behavior. The preparation of the titanate incorporated anodized Mg alloy (Ti-AMg) is a facile solution to overcome the implant-associated bacterial infections with required biological functions including progression of bone ingrowth and biocompatibility. [ABSTRACT FROM AUTHOR]

This can help to prevent the build-up of corrosion products on the surface of the substrate and can significantly reduce the risk of corrosion. For example, this Special Issue will discuss the various types of coatings available for corrosion protection, including organic coatings (e.g., paints, lacquers), inorganic coatings (e.g., ceramics, metallic coatings) [[9]], and composite coatings (e.g., metal-matrix composites) [[11]]. Corrosion is a costly and dangerous phenomenon that affects many industries, leading to significant economic losses and, in some cases, catastrophic failures. Overall, advanced corrosion protection through coatings and surface rebuilding is an important and effective way to protect metals from corrosion. [Extracted from the article]

In this research work, the analysis of mechanical and metallurgical properties of AZ91D + XCe + XLi cast magnesium (Mg) alloys in adding cerium (Ce) and lithium (Li), where X can be varied. The destructive tests viz. mechanical test, tensile strength test, and microhardness test are used to investigate mechanical properties of AZ91D alloy in adding various weight percentages viz. 0.5, 1, 2, of Ce and Li. This result of this present investigation reveals that there will be refinement of grain size on AZ91D alloy in adding Ce and Li. The formation of second phase Al2Ce that has superior melting point, changes the distribution of the phase Mg17Al12 from a continuous network morphological transition to a tiny and dispersive distribution along the grain boundary. Furthermore, adding Li to the AZ91D magnesium alloy lowers the corrosion current density in a 3.5 percent NaCl solution, improving the alloy's corrosion resistance. The results show that the AZ91D magnesium alloy, which contains 0.5 percent Ce + 1.0wt.%, outperforms other magnesium alloys. [ABSTRACT FROM AUTHOR]