Corrosion Of Mg Alloys Research Articles

Corrosion Rate and Mechanism of Degradation of Chitosan/TiO2 Coatings Deposited on MgZnCa Alloy in Hank's Solution.

Overly fast corrosion degradation of biodegradable magnesium alloys has been a major problem over the last several years. The development of protective coatings by using biocompatible, biodegradable, and non-toxic material such as chitosan ensures a reduction in the rate of corrosion of Mg alloys in simulated body fluids. In this study, chitosan/TiO2 nanocomposite coating was used for the first time to hinder the corrosion rate of Mg19Zn1Ca alloy in Hank's solution. The main goal of this research is to investigate and explain the corrosion degradation mechanism of Mg19Zn1Ca alloy coated by nanocomposite chitosan-based coating. The chemical composition, structural analyses, and corrosion tests were used to evaluate the protective properties of the chitosan/TiO2 coating deposited on the Mg19Zn1Ca substrate. The chitosan/TiO2 coating slows down the corrosion rate of the magnesium alloy by more than threefold (3.6 times). The interaction of TiO2 (NPs) with the hydroxy and amine groups present in the chitosan molecule cause their uniform distribution in the chitosan matrix. The chitosan/TiO2 coating limits the contact of the substrate with Hank's solution.

The uniform corrosion of biodegradable Mg alloy induced by protein addition in Hanks’ balanced salt solution

The localized corrosion caused by the interphase potential differences and incompleteness of the corrosion product layer results in the premature failure of Mg alloys. In biomedical applications, understanding about the corrosion behavior of Mg alloys in complex environment is still insufficient. In this work, mechanical tests after corrosion were employed to indirectly but generally reflect the localized corrosion of Mg alloy in the protein-containing electrolytes. The results reveal that protein alters the Mg corrosion mode to uniform corrosion and an appropriate amount of protein is beneficial for maintaining its mechanical bearing capacity. This work is helpful for understanding the corrosion behavior of Mg alloys and consummating degradation evaluation systems for Mg alloys.

Improved corrosion resistance and biocompatibility of magnesium implants by cathode-deposited polypyrrole/dicalcium phosphate dihydrate composite coating

As a new-generation of concerned biomedical metal implants, magnesium (Mg) alloy has the degradability, biocompatibility and mechanical properties close to human bones that inert metals do not have. However, the side effects caused by rapid degradation become the biggest obstacle restricting its practical application. Here, we report that the preparation of polypyrrole/calcium phosphate (PPy/CaP) composite coating on Mg alloy by the application of the cathode deposition twice in a row, which delayed the corrosion of Mg alloy and reduced its corrosion current density, the biocompatibility was also greatly improved. This method is simple to operate, and could get a tightly bonded PPy coating on active metals without passivation treatments. It also avoids the substrate exposure due to the high solubility of the single electrodeposited calcium phosphate coating, and finds the future direction for application of electrodeposited modified Mg alloy.

Quantifying of the Effects of Secondary Phases on Corrosion in Mg-RE Alloys by X-Ray Computed Tomography

The secondary phases of Mg alloys are closely related to corrosion. In this work, the correlation between secondary phases and corrosion in a Mg-6Gd-Y-Al alloy was identified by x-ray computed tomography technology. The influence of aging treatment on secondary phases of Mg alloys during corrosion was studied. The corrosion morphology of Mg alloy was examined in situ using three-dimensional reconstruction techniques. To quantify the effects of secondary phases on the corrosion of Mg alloys, the variation of average number density, average equivalent diameter, and average distance were investigated. The corrosion rate of Mg alloys was measured by electrochemical tests. It was found that after low temperature aging at 95°C, the corrosion rate of Mg alloys decreased by approximately 50%. This is due to the uniform distribution of secondary phases which increases the local overall potential and improves the protection of surface films.

Anodization and Plasma Electrolytic Oxidation Treatments of AZ91D Mg Alloy in Alkaline Aqueous Solutions

Mg alloys, such as AZ91 (Mg-9mass%Al-1mass%Zn), are lightweight materials with excellent mechanical properties. The applications of Mg alloys in automobiles could significantly contribute to reducing carbon dioxide emissions. Mg alloys are fully recyclable and abundantly available, which increases their desirability in light of rising environmental consciousness. However, the low corrosion resistance of Mg alloys is one of the major limitations to further applications.In Mg alloys, corrosion behavior is known to be related to the microstructure. During the real-time in situ observation of the corrosion process under galvanostatic polarization, filiform corrosion proceeded along the outside of the β phase (in lamellar α + β microstructure and along the α-mother phase 1. Furthermore, the β phase exhibited a higher potential in the OCPs of each phase and a small area with the boundary in 0.1 M NaCl at pH 8.0 2. Thus, the surface films of β phases was thought to suppress the corrosion of Mg alloys. Mg alloys can be treated by anodic oxidation or plasma electrolytic oxidation to obtain excellent corrosion resistance. The latter is similar to anodic oxidation but applies a higher voltage, which causes a discharge on the electrode surface and the resulting plasma modifies the oxide film significantly.In this study, anodic oxidation and plasma electrolytic oxidation were performed on AZ91D Mg alloy in alkaline solutions such as sodium phosphate. This study aims to compare the two methods in the same solution and to produce an Al-rich surface film with excellent corrosion resistance.In anodic oxidation, the size of the electrode area was approximately 1 cm2. The surface of the specimen was coated with epoxy resin, followed by paraffin. The reference electrode was Ag / AgCl (3.33 M KCl). The experiments were performed at 25 ℃. The scan rate of potentiodynamic polarization was set at 23 mV min-1. The starting potential was set at 20 mV lower than the open-circuit potential. The anodic oxidation treatments were terminated at 0 V, 3 V, and 5 V. Plasma electrolytic oxidation was performed with a liquid volume of 500 mL. The sample was mounted on a resin holder. The electrode surface was approximately 50 mm2. A Pt plate was used as the counter electrode. The sample and the counter electrode were fixed at a distance of 0.5 cm. A plasma-generating power supply was used. The solution was cooled down to 20 ℃ while the voltage was applied. The frequency and the pulse interval were adjusted. The voltage and type of solution were changed to produce the film. Z. Shao, M. Nishimoto, I. Muto, and Y. Sugawara, Corrosion Science, 192, 109834 (2021).Z. Shao, M. Nishimoto, I. Muto, and Y. Sugawara, Journal of Magnesium and Alloys, 11, 137-153 (2023).

Effect of ultrasonic shot peening and intermediate cerium salt conversion bath treatment controlling corrosion of Mg-Y-Zn-based alloy in salt water

Ultrasonic shot peening (USP) is often regarded as beneficial in mitigating corrosion of Mg alloys. However, increasing surface roughness induced by USP promotes localized corrosion pitting. Herein, we show that an intermediate phosphate bath treatment (CePT) before USP can minimize the surface roughness and ameliorate corrosion resistance of Mg-4.0Y-4.0Zn-0.5Zr-0.2Ca alloy (wt.%) in 0.1 M NaClsolution. In this regard, WZ44 alloy was subjected to Ce(NO3)3 + NaH2PO4bath treatment followed by USP for 30 s using AISI52100 steel balls and vice versa. The sub-surface features ofspecimens analyzed using XRD, FESEM, surface topography, and Vickers hardness reveal that CePT coating before USP increases microhardness (∼142–149 HV0.05 vs ∼ 125–135 HV0.05) and decreases surface roughness (Ra = 1.91–2.38 μm vs Ra = 2.58–2.76 μm). Potentiodynamic polarizationand electrochemical impedance spectroscopy demonstrate that corrosion current decreased (Icorr ∼ 9.81–13.69 µA/cm2 vs. ∼ 23.82–26.22 µA/cm2), coating (R1), and polarization resistance (R2) increased to ∼ 1704–1907 Ω.cm2,and ∼ 1834–1902 Ω.cm2, respectively,for specimens subjected to USP + CePT treatment together indicating superior corrosion resistance.Overall, an intermediate CePT before USP can effectively minimize corrosion pitting phenomena of WZ44 alloy in chlorinated solution by developing a ceramic coating interlocked with surface acting as a barrier between the metal/solution interface.

Understanding the corrosion of Mg alloys in in vitro urinary tract conditions: A step forward towards a biodegradable metallic ureteral stent

Ureteral stents play a fundamental role in modern time urology. However, following the deployment, stent-related symptoms are frequent and affect patient health and quality of life. Using biodegradable metals as ureteral stent materials have emerged as a promising strategy, mainly due to the improved radial force and slower degradation rate expected. Therefore, this study aimed to characterize different biodegradable metals in urinary tract environment to understand their propensity for future utilization as base materials for ureteral stents. The corrosion of 5 Mg alloys – AZ31, Mg-1Zn, Mg-1Y, pure Mg, and Mg-4Ag – under simulated urinary tract conditions was accessed. The corrosion layer of the different alloys presented common elements, such as Mg(OH)2, MgO, and phosphate-containing products, but slight variations in their chemical compositions were detected. The corrosion rate of the different metals varied, which was expected given the differences in the corrosion layers. On top of this, the findings of this study highlighted the significant differences in the samples' corrosion and corrosion layers when in stagnant and flowing conditions. With the results of this study, we concluded that Mg-1Zn and Mg-4Ag presented a higher propensity for localized corrosion, probably due to a less protective corrosion layer; Mg-4Ag corroded faster than all the other four alloys, and Mg-1Y stood out due to its distinct corrosion pattern, that showed to be more homogeneous than all the other four samples, making this one more attractive for the future studies on biodegradable metals.

Revealing anti-corrosion behavior of Mg alloy concrete formwork coated with release agents in Cl−-containing Portland cement paste

Anticorrosion performance of AZ41 Mg alloy coated with three different kinds of release agents was investigated embedded in Portland cement (PC) paste containing 0.6 M NaCl. Surface characterizations were employed to obtain the surface information after coated with release agents before and after embedment. Meanwhile, electrochemical methods were adopted to assess the corrosion resistance embedded in PC paste. Results demonstrated that water-based release agent led to the corrosion of Mg alloy while the oil-based release agent not only protected the Mg alloy but also exhibited the best demolding effect. Oxide films can be generated on the surface of Mg alloy after coated with release agents. The thin film after applying the water-based release agent was magnesium/aluminium oxide and hydroxide with some talcum (3MgO·4SiO2·H2O) particles. Additionally, thin films on the surface of Mg alloy after coated with emulsified and oil-based release agents were magnesium/aluminium oxide and hydroxide.

Isatin Schiff bases: A green and sustainable Mg alloys corrosion inhibitor

Mg alloys have a good application prospect and are a structural material with great application potential. However, the corrosion resistance of Mg alloys are very poor, so it is possible to develop environment-friendly and pollution-free corrosion inhibitor to inhibit the corrosion of Mg alloys and study its inhibition mechanism. Three isatin Schiff bases were synthesized and used as Mg alloys corrosion inhibitors. The results showed that in a 0.5 wt% NaCl solution, all three corrosion inhibitors had a good corrosion inhibition effect on AZ91D. The corrosion inhibition mechanism was studied by various characterization methods.

Phase-field modeling of pitting and mechanically-assisted corrosion of Mg alloys for biomedical applications.

A phase-field model is developed to simulate the corrosion of Mg alloys in body fluids. The model incorporates both Mg dissolution and the transport of Mg ions in solution, naturally predicting the transition from activation-controlled to diffusion-controlled bio-corrosion. In addition to uniform corrosion, the presented framework captures pitting corrosion and accounts for the synergistic effect of aggressive environments and mechanical loading in accelerating corrosion kinetics. The model applies to arbitrary 2D and 3D geometries with no special treatment for the evolution of the corrosion front, which is described using a diffuse interface approach. Experiments are conducted to validate the model and a good agreement is attained against in vitro measurements on Mg wires. The potential of the model to capture mechano-chemical effects during corrosion is demonstrated in case studies considering Mg wires in tension and bioabsorbable coronary Mg stents subjected to mechanical loading. The proposed methodology can be used to assess the in vitro and in vivo service life of Mg-based biomedical devices and optimize the design taking into account the effect of mechanical deformation on the corrosion rate. The model has the potential to advocate further development of Mg alloys as a biodegradable implant material for biomedical applications. STATEMENT OF SIGNIFICANCE: A physically-based model is developed to simulate the corrosion of bioabsorbable metals in environments that resemble biological fluids. The model captures pitting corrosion and incorporates the role of mechanical fields in enhancing the corrosion of bioabsorbable metals. Model predictions are validated against dedicated in vitro corrosion experiments on Mg wires. The potential of the model to capture mechano-chemical effects is demonstrated in representative examples. The simulations show that the presence of mechanical fields leads to the formation of cracks accelerating the failure of Mg wires, whereas pitting severely compromises the structural integrity of coronary Mg stents. This work extends phase-field modeling to bioengineering and provides a mechanistic tool for assessing the service life of bioabsorbable metallic biomedical devices.

Improving hydroxyapatite coating ability on biodegradable metal through laser-induced hydrothermal coating in liquid precursor: Application in orthopedic implants.

During the past decade, there has been extensive research toward the possibility of exploring magnesium and its alloys as biocompatible and biodegradable materials for implantable applications. Its practical medical application, however, has been limited to specific areas owing to rapid corrosion in the initial stage and the consequent complications. Surface coatings can significantly reduce the initial corrosion of Mg alloys, and several studies have been carried out to improve the adhesion strength of the coating to the surfaces of the alloys. The composition of hydroxyapatite (HAp) is very similar to that of bone tissue; it is one of the most commonly used coating materials for bone-related implants owing to favorable osseointegration post-implantation. In this study, HAp was coated on Mg using nanosecond laser coating, combining the advantages of chemical and physical treatments. Photothermal heat generated in the liquid precursor by the laser improved the adhesion of the coating through the precipitation and growth of HAp at the localized nanosecond laser focal area and increased the corrosion resistance and cell adhesion of Mg. The physical, crystallographic, and chemical bondings were analyzed to explore the mechanism through which the surface adhesion between Mg and the HAp coating layer increased. The applicability of the coating to Mg screws used for clinical devices and improvement in its corrosion property were confirmed. The liquid environment-based laser surface coating technique offers a simple and quick process that does not require any chemical ligands, and therefore, overcomes a potential obstacle in its clinical use.

Influence of oxalic acid on the corrosion behavior of AZ91D magnesium alloy in deionized water

Due to its light weight, Mg alloy can be applied to automotive engines and cooling systems to reduce vehicle weight, energy consumption and exhaust pollution. However, ethylene glycol-type coolants can be oxidized into oxalic acid, glyoxylic acid and other substances at high temperature, which can cause the damage of Mg alloy. In this paper, electrochemical methods, hydrogen evolution and surface analysis methods were used to study the influence of oxalic acid on the corrosion behavior of AZ91D magnesium alloy in deionized water. The results indicated that the oxalic acid accelerated the corrosion of Mg alloy, and its corrosion rate increased with the concentration of oxalic acid. However, interestingly, the corrosion rate of Mg alloy in oxalic acid solution slowed as the immersed time lengthened, which could be related to the accumulation of corrosion products and the consumption of hydrogen ions. The main corrosion product of the corrosion of Mg alloy in oxalic acid solution was composed of magnesium oxalate.

Multifunctional coating on magnesium alloy: Superhydrophobic, self-healing, anti-corrosion and wear-resistant

Superhydrophobic coating (SHC) was fabricated on magnesium (Mg) alloy by sequential surface etching, in-situ growth of MgAl-layered double hydroxides (LDHs), and modification of octadecyl-trimethoxy-silane (OTMS). The so-fabricated SHC possessed high contact angle above 150° and low sliding angle below 10° by using the probe droplet of aqueous solution of HCl (pH = 2), NaOH (pH = 13), NaCl (3.5 wt.%) or others such as milk, cola, and tea. The lubricant behavior as well as wear resistance was enhanced by such a SHC as compared with the bare Mg alloy. Moreover, corrosion of Mg alloy was greatly slowed by such a SHC which maintained long-term hydrophobic property after corrosion immersion in aqueous solution of NaCl for 6 weeks. The scratch on the SHC could be self-healed by immersing into water due to the hydrolytic polycondensation of silane and corrosion decomposition of LDHs within 8 days.

Bioabsorbable WE43 Mg alloy wires modified by continuous plasma electrolytic oxidation for implant applications. Part II: Degradation and biological performance

The corrosion, mechanical degradation and biological performance of cold-drawn WE43 Mg wires were analyzed as a function of thermo-mechanical processing and the presence of a protective oxide layer created by continuous plasma electrolytic oxidation (PEO). It was found that the corrosion properties of the non-surface-treated wire could be optimized by means of thermal treatment within certain limits, but the corrosion rate remained very high. Hence, strength and ductility of these wires vanished after 24 h of immersion in simulated body fluid at 37 °C and, as a result of that rather quick degradation, direct tests did not show any MC3T3-E1 preosteoblast cell attachment on the surface of the Mg wires. In contrast, surface modification of the annealed WE43 Mg wires by a continuous PEO process led to the formation of a homogeneous oxide layer of ≈8 μm and significantly improved the corrosion resistance and hence the biocompatibility of the WE43 Mg wires. It was found that a dense layer of Ca/P was formed at the early stages of degradation on top of the Mg(OH)2 layer and hindered the diffusion of the Cl− ions which dissolve Mg(OH)2 and accelerate the corrosion of Mg alloys. As a result, pitting corrosion was suppressed and the strength of the Mg wires was above 100 MPa after 96 h of immersion in simulated body fluid at 37 °C. Moreover, many cells were able to attach on the surface of the PEO surface-modified wires during cell culture testing. These results demonstrate the potential of thin Mg wires surface-modified by continuous PEO in terms of mechanical, degradation and biological performance for bioabsorbable wire-based devices.

The performance of hybridized nano-ceramics on the microstructure and corrosion of Mg alloy in an auto-engine cooling system

This current novel research focuses on developing a hybrid magnesium-based composite through the spark plasma sintering process with an interest in the improvement of mechanical properties and corrosion resistance of Mg Alloy in an auto-cooling system. AZ91D was selected as the primary Mg alloy and it was reinforced with hybridized AlN-VB at a sintering temperature of 500 °C, a heating rate of 75 °C/min, a pressure of 30 MPa, and a dwell time of 5 min. The microstructure of the sintered composite at varying weight constituents shows a homogenous dispersion of the reinforcing material and refinement of the inherent eutectic β-Mg17Al12 phase. The refinement of the phase yielded a small grain size of 16.6 ± 0.20 μm by the MgAZ91D-8wt%AlN-8wt%VB composite compared to the coarse grain size of 36.1 ± 0.9 μm by the unreinforced MgAZ91D. likewise, a higher microstrain value of 7.57E-2 was achieved by the composite with the highest reinforcing constituents. The load-displacement curve shows a gradual shift to the left following the inclusion of the reinforcing substances, this implies a higher resistance to penetration as a result of higher nanohardness and elastic modulus. The corrosion behavior of the sintered composite was examined in a simulated auto-engine cooling system using ethylene-glycol and corrosive water. The Unreinforced MgAZ91D shows a high corrosion rate (Cr) of 2.2217 mm/year, a higher degree of disorderliness (n) of 0.8829, and a low charge resistance transfer (Rct) of 4.6143 kΩcm2. However, the corrosion rate decreases rapidly to 0.0475 mm/year and the Rct to 20.9543 kΩcm2 at MgAZ91D-8wt%AlN-8wt%VB composite.

Corrosion behavior of severely plastically deformed Mg and Mg alloys

Magnesium (Mg) alloys have several advantages, such as low density, high specific strength and biocompatibility. However, they also suffer weak points, such as high corrosion, low formability and easy ignition, which makes their applications limited. Many studies have been conducted to overcome these disadvantages and further improve the advantages of Mg alloys. Severe plastic deformation (SPD) is one of the most important techniques and has great effects on the microstructure refinement of Mg alloys and improvements in their strength and formability. Several researchers have studied the corrosion behavior of SPD-processed Mg alloys in recent decades. However, these studies have reported some controversial effects of SPD on the corrosion of Mg alloys, which makes the research roadmap ambiguous. Therefore, it is important to review the literature related to the corrosion properties of Mg alloys prepared by SPD and understand the mechanisms controlling their corrosion behavior. Effective grain refinement by SPD improves the corrosion properties of pure Mg and Mg alloys, but control of the processing conditions is a key factor for achieving this goal because texture, dislocation density, size and morphology of secondary phase also importantly affects the corrosion properties of Mg alloys. Reduced grain size in the fine grain-size range can decrease the corrosion rate due to the increased barrier effect of grain boundaries against corrosion and the formation of a stable passivation layer on the surface of fine grains. Basal texture reduces the corrosion rate because basal planes with the highest atomic planar density are more corrosion resistant than other planes. Increased dislocation density after SPD deteriorates the corrosion resistance of the interior grains and thus proper annealing after SPD is important. The fine and uniform distribution of secondary phase particles during SPD is important to minimize the micro-galvanic corrosion effect and retain small grains during annealing treatment for removing dislocations.

The Initial Corrosion Behavior of AZ31B Magnesium Alloy in Chloride and Sulfate Solutions

The initial corrosion of Mg alloys is important for the conversion coating treatment, by which the conversion coating is formed in a few minutes of immersion in the conversion solution. This study detailed the initial corrosion of AZ31B Mg alloy in chloride and sulfate solutions by acquiring the open circuit potential, optical image and hydrogen evolution, together with the post-immersion TEM and XPS characterization. Before the breakdown of the surface film, more hydrogen evolved in the SO4 2− solution than in Cl− solution, and the corrosion products formed in the former were thicker than in the latter. The initial corrosion of AZ31B was thus more severe in SO4 2− solution than in Cl− solution, which is different from the typical role of Cl− ions in metal corrosion. Local attack at nanometric scales was observed in Cl− solution, but not in SO4 2− solution. The presence of SO4 2− in Cl− solution mitigated local attack and the corrosion products were more uniform, due to the competitive adsorption effect of SO4 2−.

Fabrication of electroactive poly(γ‐glutamic acid) coating for improving corrosion resistance and cytocompatibility of magnesium alloy

AbstractAlthough magnesium (Mg) and its alloys are promising biodegradable materials for orthopedic implants, rapid and uncontrollable degradation of Mg is still a challenge for clinical applications. In this work, electroactive polymer coatings were prepared to improve the corrosion resistance and cytocompatibility of Mg alloys. Amphiphilic electroactive tetraaniline (TANi)‐conjugated poly(γ‐glutamic acid) (γ‐PGA) with various TANi modification rates (γ‐PGA–TANi10, γ‐PGA–TANi20, γ‐PGA–TANi27) were first synthesized. γ‐PGA–TANi colloidal particles, prepared by a self‐assembly method, were then coated on Mg alloys by electrophoretic deposition. The prepared γ‐PGA–TANi coatings showed a homogeneous surface and good adhesion on AZ31 Mg alloys. Electrochemical analysis and in vitro immersion tests revealed that γ‐PGA–TANi‐coated Mg exhibited superior corrosion resistance, which was mainly attributed to the electroactivity of the γ‐PGA–TANi coatings, leading to the rapid formation of a passivation layer to prevent the further corrosion of Mg alloys. Furthermore, the γ‐PGA–TANi alloy coatings efficiently regulated Mg2+ release and pH value of coated Mg alloy during immersion for 40 days. In comparison with bare Mg alloy, the coated Mg alloy also showed better cytocompatibility, where L929 cells emerged with a good cell adhesion and viability. These results indicate that electroactive γ‐PGA–TANi coatings have promising potential for corrosion resistance of Mg alloys. © 2022 Society of Industrial Chemistry.

Designing attapulgite-based self-healing superhydrophobic coatings for efficient corrosion protection of magnesium alloys

Magnesium (Mg) and its alloys are susceptible to corrosion, which affects their large-scale applications. The traditional superhydrophobic coatings for corrosion protection of Mg substrates are particularly fragile and easily damaged after prolonged exposure to harsh conditions. Herein, a superhydrophobic ODA/PDA/APT-Ce3+ (OPA-Ce3+) coating with corrosion inhibition and self-healing properties was proposed to prevent corrosion of Mg alloy via combining the cerium nitrate loaded attapulgite (APT), polydopamine (PDA) and octadecylamine (ODA). Once the OPA-Ce3+ coating was corroded, the Ce3+ adsorbed by the APT were released to form insoluble cerium oxide and hydroxides, thereby inhibiting the penetration of the corrosive substance and preventing further occurrence of corrosion. Furthermore, the OPA-Ce3+ coating exhibited favorable self-healing ability against chemical damage, which could recover its superhydrophobicity under solar exposure after O2 plasma etching. The impedance modulus (|Z|0.01 Hz) of OPA-Ce3+ coating was about 3 orders of magnitude higher than that of Mg substrate after being exposed to 3.5 wt% NaCl solution for 15 days, showing outstanding long-lasting anticorrosion performance. Moreover, the abrasion resistance and chemical stability of the as-fabricated coating were also excellent. This work is expected to provide a new perspective for preparing cost-effective and durable anticorrosion coating on metal substrates.

Research advances of magnesium and magnesium alloys worldwide in 2021

More than 4000 papers in the field of Mg and Mg alloys were published and indexed in Web of Science (WoS) Core Collection database in 2021. The bibliometric analyses indicate that the microstructure, mechanical properties, and corrosion of Mg alloys still are the main research focus. Mg ion batteries and hydrogen storage Mg materials have attracted much attention. Significant contributions to the research and development of magnesium alloys were made by Chongqing University, Shanghai Jiaotong University, and Chinese Academy of Sciences in China, Helmholtz Zentrum Hereon in Germany, Ohio State University in the United States, the University of Queensland in Australia, Kumanto University in Japan, and Seoul National University in Korea, University of Tehran in Iran, etc.. This review is aimed to summarize the progress in the development of structural and functional Mg and Mg alloys in 2021. Based on the issues and challenges identified here, some future research directions are suggested.