Corrosion Rate Of Mg Research Articles

Mg ZX10 alloy for biomedical applications: Surface characterization and comparative corrosion studies under simulated biological conditions

Biodegradable magnesium (Mg)-based alloys emerge as potential intracorporeal implants for clinical application in bone tissue, the cardiovascular and the nervous systems. The surfaces of control (non-sterilized) and sterilized (180 °C 1 h) Mg ZX10 alloy were studied. The alloy evolution in SBF (simulated saline solution) and in DMEM (Dulbecco's Modified Eagle Medium) with fetal calf serum (FCS) was investigated using: Raman spectroscopy, FTIR-ATR, electrochemical assays and scanning electron microscopy (SEM). The Mg ZX10 microstructure analysis revealed an average grain size of 23.4 ± 11.02 and 31.6 ± 13.07 μm, considering the minor and major axis, respectively. In addition, the Mg ZX10 microstructure exhibited a homogeneous grain distribution. The contact angle formed between the water and the surface of control Mg ZX10 and sterilized were 32.24° ± 1.53 and 46.76° ± 0.83, respectively. Consequently, both groups of samples exhibited hydrophilic surfaces. Furthermore, the free surface energy of control Mg ZX10 was 63.23 ± 0.72 mN/m and sterilized Mg ZX10 was 52.31 mN/m ± 1.25, those energy values were in agreement with previous reports. Upon immersion in SBF, Raman spectroscopy detected the presence of magnesium oxides-hydroxides, phosphates and carbonates compounds in both groups of samples without significant differences. FTIR spectra of the sterilized alloys, after immersion in DMEM + FCS, showed the presence of amide and carbon-carbon bonds, magnesium-oxides, as well as phosphates and carbonates groups. These findings suggested the deposition of organic and inorganic compounds on the alloy surface. Electrochemical assays carried out in SBF demonstrated a slight reduction in the degradation of the sterilized alloy compared to control Mg ZX10. Moreover, a substantial decrease in the corrosion behavior of the sterilized alloy immersed in DMEM + FCS with respect to the same alloy immersed in SBF was observed. SEM images showed that the alloy, previously immersed in SBF, exhibited degradation cracks. Contrary, the sterilized alloy surface immersed in DMEM + FCS was more homogenous with deposits of structures similar to hybrid nanoflowers. Based on these results, this sterilization process does not alter the chemistry of Mg ZX10 alloy surface and, even, its application exhibits an advantage since the high corrosion rate of Mg in physiological media. Furthermore, the organic-inorganic structures adsorbed, after alloy immersion in DMEM + FCS, could decrease corrosion behavior.

Enhanced corrosion resistance of Mg and Mg alloys with fs-laser printed hydrophobic and periodically microrippled surface for armor application

Magnesium (Mg) and its alloys have properties such as high strength-to-weight ratio and good castability, which make them quite promising in industrial applications. Future widespread application of them needs to overcome the limitations such as the fast corrosion rate of Mg and Mg alloys. In this study, an anticorrosion armor with was printed using femtosecond (fs) laser direct writing method. This protective armor is covered with controllable micro-nano structures. Thus, it has a controllable water contact angle ranged from 68° to 158°. In addition, due to the fs laser energy deposition, a grain refined layer less than 15 μm consisting of nanocrystals forms on the surface. Under the synergistic effects of the superhydrophobic surface and nanocrystal layer, Mg and Mg alloys (AZ91D) exhibit significantly enhanced corrosion voltage and exponentially decreased corrosion current density. In particular, pitting on the surface is largely improved, and the corrosion pits on the surface after laser-treatment are approximately 200 times smaller in depth (<2.5 μm) than those of the pristine surface (531 μm). Therefore, the armor on Mg and Mg alloys with enhanced corrosion resistance can be successfully fabricated by the fs-laser direct printing method, extensively used in Mg and Mg alloys applications.

Insight of the role of cooling method and soil environment on the corrosion behavior of Mg–2Nd alloys

Understanding the corrosion behavior of Mg alloys in the soil environments is crucial to preventing catastrophic accidents in their facilities due to the soil corrosion. The Mg–2Nd alloys were exposed to the soil after cooling in different ways under the same heat treatment conditions. The corrosion mechanisms of Mg–2Nd alloy in the soil are mainly affected by corrosion micro-batteries and macro-batteries. The more precipitates, the more severe micro-galvanic corrosion are formed. Meanwhile, the corrosion product films are damaged by micro-galvanic corrosion, which have a serious impact on the differential concentration of oxygen and differential infiltration of rainwater corrosion. The Mg–2Nd alloy buried in the soil with high water content and low oxygen permeability in corrosive macro-batteries will be corroded into anodes, thereby accelerating the corrosion rate of Mg–2Nd alloy in this part. Furthermore, the formation of corrosion product MgCO3 reduces the electrochemical activity of the sample surface, thereby reducing the corrosion rate of Mg–2Nd alloy in the soil. Therefore, the Mg–2Nd alloy after water-cooling has the best corrosion behavior in the soil environment.

Exploring the corrosion inhibition of magnesium by coatings formulated with nano CeO and ZrO particles

ABSTRACT. In this study, zirconium oxide (ZrO)-cerium oxide (CeO) based composite coatings were fabricated using doctor blade method to protect pure magnesium from corrosion. The effects of ZrO and CeO on corrosion resistance of magnesium coatings were investigated using Tafel polarization method. Uniform deposition of composite coating without micro-voids was observed from scanning electron microscopy (SEM) analysis. The results exhibit that the addition of CeO show a higher corrosion resistance in comparison with the specimen coated without CeO in the electrolyte and bare Mg, and also it reduces the corrosion rate of Mg up to 3.67 x 10-5 mpy. Surface morphology of the so developed composite coating result a minimum corrosion on the surface. The usage of ZrO/CeO as coating material is a promising anticorrosive measure for Mg and its alloys due to its elevated corrosion resistance and durability.&#x0D; &#x0D; KEY WORDS: Magnesium, Cerium oxide synthesis, composite coating, Tafel polarization, Surface morphology&#x0D; Bull. Chem. Soc. Ethiop. 2023, 37(5), 1299-1306. &#x0D; DOI: https://dx.doi.org/10.4314/bcse.v37i5.20

Characterization and Biocompatibility Assessment of Boron Nitride Magnesium Nanocomposites for Orthopedic Applications.

Magnesium (Mg) has been intensively studied as a promising alternative material to inert metallic alloys for orthopedic fixation devices due to its biodegradable nature inside the body and its favorable biocompatibility. However, the low mechanical strength and rapid corrosion of Mg in physiological environments represent the main challenges for the development of Mg-based devices for orthopedic applications. A possible solution to these limitations is the incorporation of a small content of biocompatible nanoparticles into the Mg matrix to increase strength and possibly corrosion resistance of the resulting nanocomposites. In this work, the effect of adding boron nitride (BN) nanoparticles (0.5 and 1.5 vol.%) on the mechanical properties, corrosion behavior, and biocompatibility of Mg-based nanocomposites was investigated. The properties of the nanocomposites fabricated using powder metallurgy methods were assessed using microstructure analyses, microhardness, compression tests, in vitro corrosion, contact angle, and cytotoxicity tests. A significant increase in the microhardness, strength, and corrosion rates of Mg-BN nanocomposites was detected compared with those of pure Mg (0% BN). Crystalline surface post-corrosion byproducts were detected and identified via SEM, EDX, and XRD. Biocompatibility assessments showed that the incorporation of BN nanoparticles had no significant impact on the cytotoxicity of Mg and samples were hydrophilic based on the contact angle results. These results confirm that the addition of BN nanoparticles to the Mg matrix can increase strength and corrosion resistance without influencing cytotoxicity in vitro. Further investigation into the chemical behavior of nanocomposites in physiological environments is needed to determine the potential impact of corrosive byproducts. Surface treatments and formulation methods that would increase the viability of these materials in vivo are also needed.

Electrochemical Studies of Magnesium Coated with Modified Chitosan and Electrosprayed as an Anticorrosive Protection Method in Bone Repair

Magnesium (Mg) is essential for the metabolic reactions of the human body and is known for its biocompatibility, its mechanical and physical properties are similar to human bone, which is why it is considered to have high potential in biomedical applications such as temporary and resorbable implants. Through surface modifications, the high tendency to corrosion of Mg could be controlled, such as biodegradable membranes that prevent the passage of chloride ions present in the human organism. To prepare the membrane, solutions of chitosan modified with gelatin and/or glutaraldehyde are used and by means of the electrospray method applied to protect the Mg. To simulate body fluid conditions a Kokubo saline solution (BFK) was prepared. The study focuses on evaluating the corrosion rate of Mg with a coating made of a chitosan electrosprayed membrane, applying electrochemical measurements of electrochemical impedance spectroscopy and linear polarization resistance. The key additive to improve the behavior of the membranes was observed with the use of gelatin, where the membrane with the best results lowing corrosion rates is the Mg CH+GE+GL system, which it was observed with very good physical integrity in the images of morphological analyzes of the surface after 30 days of exposure.

Electrochemical Study of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;/ Industrial Waste Coating on Mg Substrate via Sol-Gel Method

Industrial waste is primarily handled using landfills in both developed and developing countries. While there has been a significant rise in solid waste reduction, reuse, and recycling, landfill disposal will inevitably remain the most commonly used form of waste management. Although landfilling provides an economic means of waste disposal, it can lead to environmental degradation by releasing various contaminants if not managed properly. In this work, industrial waste from electrostatic precipitators (ESP) will be beneficial for the production of coatings on metal substrates. The sol-gel coating method have been attempted for deposition on pure Mg samples. Using the potentiodynamic polarization (PDP) method and hydrogen evolution analysis, the effectiveness of the coating, which is the corrosion resistance was analyzed. A minimal application of Tetraethyl orthosilicate (TEOS) in the ESP dust solution has been shown to substantially reduce the corrosion rate of Mg. This is likely due to the impact of its concentrations through the sol-gel process that could increase the size of the particle shape or growth.

Insight into microbiologically induced corrosion performance of magnesium in tryptic soy broth with S. aureus and E. coli

In this research, microbiologically induced corrosion (MIC) performance of magnesium in tryptic soy broth with S. aureus or E. coli were systematically explored. The results showed that magnesium in biotic solution presented higher mass loss, thicker degradation product layer and more severe pitting corrosion compared to abiotic solution after 24 h of immersion. Electrochemical measurements including EIS spectra and polarization curve further suggested that the corrosion rate of Mg in biotic solution increased during the early stage owing to the decrease of pH, which was originated from the consumption of glucose and the resulting accumulation of acidic metabolites. However, corrosion rate subsequently decreased because of the reduction of acidic metabolites and production of alkaline compound as well as the corrosion protection provided by the corrosion product and biofilm. Moreover, the corrosion rate of magnesium in high concentration of S. aureus and E. coli solution was larger than that in low concentration of S. aureus and E. coli solution, respectively during the initial stage, but subsequently presented a reverse variation. In addition, more severe corrosion of magnesium was observed in S. aureus solution in comparison with E. coli solution. These results suggested that the MIC performance of magnesium was closely related to the concentration and species of bacteria.

The influence of SrCl2 on the corrosion behavior of magnesium

Abstract The influence of SrCl2 on the corrosion behavior of magnesium (Mg) in 3.5 wt.% NaCl was evaluated by immersion testing, electrochemical measurement and the examination of the corrosion morphology. A small addition of SrCl2 decreased the corrosion rate of Mg. In contrast, an excess of SrCl2 increased the corrosion rate of Mg, even higher than that in 3.5 wt.% NaCl. There is a competition effect of the SrCl2 on the corrosion behavior of Mg in 3.5 wt.% NaCl. The Sr2+ can improve the protection of corrosion product film through the formation of SrCO3. While the Cl− can damage the protection of the corrosion product film. The Mg specimen achieved the best corrosion resistance in 3.5 wt.% NaCl + 0.005 mol L−1 SrCl2.

Electrochemical techniques for monitoring the biodegradability of nanocomposite Mg-alloy/HA for repairing bone fracture

Mg and its composites are considered attractive candidates for supplying biomedical implantation. Mg-alloys are gaining popularity for biomedical implant applications, particularly bone regeneration because they have characteristics that are like those of natural bone. Simulated body fluid (SBF) is an electrolyte that is often utilized in vitro corrosion investigations. Using each SBF module individually and in combination, this research evaluates the corrosion effects on the system. pH alterations hasten the degeneration of the organism's pH and it was decided to explore the corrosion of Mg in an SBF. In this study, the effect of pH changes on the corrosion rate of Mg immersed in standard SBF solution was investigated in detail. According to previously published research, the corrosion process of Mg has been substantiated by scanning electron microscopy examinations of damaged surface morphology. In this investigation, pH 7 was determined to be the optimal pH for physiological fluids since it is neutral. To accomplish these aims, researchers examined Mg–2 wt.% Zn–0.5 wt.% Ca (ZC21) alloy pins microstructurally and mechanically, as well as the degradation of the alloy pins and their interactions with the SBF solution. The degradation of bone and its cytocompatibility with other substances. The degradation control of Mg-alloy occurred at a much slower rate than that of Mg alone. Bone cell development on the applied nano alloy is visible on SEM-EDS charts, demonstrating that this alloy is extremely compatible with human bone and that its usage as a stent for bone fracture is highly suggested in this study.

The influence of the protein bovine serum albumin (BSA) on the corrosion of Mg, Zn, and Fe in Zahrina’s simulated interstitial fluid

We evaluated the corrosionof biodegradable metals Mg, Zn, and Fe in Zahrina’s interstitial fluid (ZIF P) for treatment of pelvic organ prolapse. The corrosion rates for Mg alloys EV31A and WE43 were similar to literature values 0.20–0.33 mm/y for in vivo subcutaneous implantation, indicating that ZIF P was a good model for Mg. ZIF P was not a good model for Zn. There is not enough in vivo data for Fe to make an assessment. BSA increased the corrosion rate of Mg attributed to BSA chelation, inhibited the corrosion of zinc, and had little effect on iron.

Improvement of Corrosion Resistance and Biocompatibility of Biodegradable Mg–Ca Alloy by ALD HfZrO2 Film

Polycrystalline HfZrO2 (HZO) film can be fabricated on as-extruded Mg–Ca alloy, which is identified by the results of XRD and TEM. HZO film can improve the corrosion resistance of as-extruded Mg–Ca alloy to further result in a decrease in the corrosion rate of Mg–Ca alloy. Corrosion current density, pH value evaluation, and the corrosion surface image provide evidence of improvement in corrosion rate. Compared with ZrO2 film, HZO film shows better short-term corrosion resistance. The results of WST-1 assay and LDH assay show that HZO film has low toxicity and is suitable for the protective coating of biological implants.

Biomimetic hydroxyapatite (HAp) coatings on pure Mg and their physiological corrosion behavior

The deposition of bioactive hydroxyapatite (HAp) coatings on pure magnesium (Mg) surfaces was studied. A modification of the biomimetic deposition method was used, which consisted in the incorporation of a supersaturated calcification solution (SCS). Different preparation parameters were modulated to obtain HAp and/or doped apatite coatings with different characteristics. The influence of the surface pre-treatments and soaking time in SCS on the physicochemical properties and the corrosion performance of the biomimetic HAp coatings were evaluated. Two different pre-treatments were explored to condition the sample’s surface for the biomimetic HAp deposition. After the surface pre-treatments, the Mg samples were covered with HAp coatings by soaking in SCS during two immersion periods specifically chosen for this study: 2 h and 6 h, respectively. Scanning electron microscopy, coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman Spectroscopy, and Fourier transform infrared (FTIR), were applied for the chemical, morphological, and structural characterization of the resulting biomimetic HAp-coatings. The in vitro corrosion behavior was studied by open circuit potential (OCP) measurements and electrochemical impedance spectroscopy (EIS) during immersion tests in Ringer’s physiological solution for up to 14 days. The results showed that HAp coatings were successfully deposited on the pure Mg substrates. Furthermore, the corrosion studies in Ringer’s solution showed that HAp coating behavior depends not only on the pre-treatment type but also on the immersion time in SCS. These results open the door to propose different strategies to control—on demand—the corrosion rate of Mg coated with biomimetic HAp. These systems could be a promising alternative for designing and developing new temporary implants for the human body.

A new generation of highly customized Mg alloy-based implants

In the last years, the precision and personalized medicine is pushing the biomedical research efforts towards the direction of implant surgery requiring only 1-step approach: this goal has been achieved after the introduction of resorbable implants. The resorbable prosthetic support is indicated for temporary prosthetic applications, such as bone fractures fixation, or all those conditions usually treated with metal implants then removed with a second surgery, just after the healing of the bone defect. Biodegradable, bioactive and customizable implants for the treatment of bone fractures, both efficient in bearing the functional loads, and showing good biocompatibility and degradation properties matching the bone tissue healing, are still lacking. These premises have led to consider Magnesium (Mg) and its alloys as very promising candidates for the development of temporary, resorbable implants. However, the very high corrosion rate of Mg is the main problem, not yet solved. The material needs to be properly treated/coated, as well as manufactured, in order to design the most suitable duration of the temporary prosthesis permanence in situ. An innovative and interdisciplinary approach has been developed within the M. Era-Net ISIDE project and it is here briefly detailed with a special focus on the highlighted application fields.

Corrosion process of Mg–Sn alloys revealed via in situ synchrotron X-ray radiography

Corrosion process of Mg–Sn alloys is investigated via in situ synchrotron X-ray radiography, and corrosion rates are compared under potentiostatic and static immersion conditions. The occurrence and extension of corrosion pits are directly observed. The fine grains and higher volume of Mg2Sn in Mg–9Sn alloy reduce the anodic current density at −1.5 V potentiostatic polarization. However, the peeling of Mg2Sn phases off the alloy matrix increases the corrosion, and the corrosion rate of Mg–Sn alloys depends on the cathodic reaction rather than anodic current density in static immersion condition.

Microstructural Evolution and Biodegradation Response of Mg–2Zn–0.5Nd Alloy During Tensile and Compressive Deformation

The effect of deformation behavior on the in vitro corrosion rate of Mg–2Zn–0.5Nd alloy was investigated experimentally after uniaxial tensile and compressive stress. The microstructure and texture were characterized using electron backscattered diffraction and X-ray diffraction, while potentiodynamic polarization and immersion tests were used to investigate the corrosion response after deformation. The result reveals that applied compressive stress has more dominant effect on the corrosion rate of Mg–2Zn–0.5Nd alloy as compared to tensile stress. Both tensile and compressive strains introduce dislocation slip and deformation twins in the alloy, thereby accelerating the corrosion rate due to the increased stress corrosion related to dislocation slips and deformation twins. The {10 $$\bar{1}$$ 2} tension twinning and prismatic slip were the major contributors to tensile deformation while basal slip, and {10 $$\bar{1}$$ 2} tension twin were obtainable during compressive deformation. The twinning activity after deformation increases with the plastic strain and this correlates with the degradation rate.

Alloying and brushite coating improve corrosion resistance of magnesium in a simulated physiological environment

While magnesium (Mg) and its alloys have been regarded as encouraging orthopaedic implant materials, the high corrosion rate limits their application. This study determines how alloying and brushite coating affected the corrosion rate of Mg in vitro. The corrosion behaviours of pure Mg, Mg-Nd-Zn-Zr alloy (Jiao Da Bio-Mg, JDBM) and brushite coated JDBM in a simulated physiological environment were comparatively evaluated. The evaluation included the surface morphology, roughness, chemical composition, structure, phase composition and functional groups of the corrosion products with the corrosion rate, pH value, Mg2+ concentration and osmotic pressure of the immersion solution. The following corrosion resistance trends were found: brushite coated JDBM > uncoated JDBM > pure Mg. The main corrosion product of the Mg alloys in the cell culture medium was MgCO3·3H2O. Compared with the pure Mg, the corrosion form of the JDBM alloys was uniform corrosion. The results showed that the addition of the Nd, Zn and Zr elements and brushite coating effectively improved the corrosion resistance of metal Mg. In addition, the power law function formula Δm = ρAtB was applied successfully to predict the mass loss of the JDBM alloy in an in vitro immersion test.

Electrochemical and corrosion behaviors of the wrought Mg–Y–Zn based alloys with high Y/Zn mole ratios

The electrochemical behaviors and corrosion resistance of the wrought Mg–Y–Zn based alloys with high Y/Zn mole ratio have been investigated in details. The results show that the corrosion resistance of the investigated Mg–Y–Zn based alloys are dependent on the modified arrangement of LPSO phase by adjusting Y/Zn mole ratios. Increasing the Y/Zn mole ratio not only greatly decreases the size of LPSO phase plates, but also leads to the precipitation of Mg 24 Y 5 phase. The corrosion rate of Mg–Y–Zn based alloys greatly increases from 7.4 mg·cm −2 ·day −1 to 11.3 mg·cm −2 ·day −1 with increasing the Y/Zn mole ratio up to 3. It should be attributed to the decreasing size of LPSO phase plates as cathodes, further increasing the hydrogen evolution kinetics. The related corrosion mechanism is discussed in details.

Review of Mg alloy corrosion rates

A review of the literature confirmed that the intrinsic corrosion rate of high-purity Mg as measured by weight-loss is 0.3 mm/y in a concentrated chloride solution. Atmospheric corrosion of Mg alloys has produced corrosion rates of Mg-Al alloys an order of magnitude lower than the intrinsic corrosion rate of Mg in a concentrated chloride solution of 0.3 mm/y. The only successful strategy to produce a Mg alloy with a corrosion rate in a concentrated chloride solution substantially less than the intrinsic corrosion rate as measured by weight loss of Mg of 0.3 mm/y has been to improve the protectiveness of the corrosion product film.

Assessment of magnesium calcium alloys improved by rare earths addition for medical implants

Biodegradable materials are used as alternative implants for orthopedic applications due suitable strength, fatigue resistance, ductility and biocorrosion resistance which are features for biodegradable implants. Mechanical properties can be improved by adding alloying elements. The decrease of the corrosion rate of Mg can be induced by modifying the structure and phase distribution. Thus, Mg alloys have been designed to meet the requirements of bone repair implant materials by adding = Calcium and Yttrium or Gadolinium. Mg based alloy with Ca and Y/Gd had been proved to be a biocompatible material, osteoconductive and biodegradable and can be used in bone repairs. The system is defined as Mg100-(n+x) Ca(n) RE(x), varying the RE concentration in order to slow the degradation process. Beside morphological combining characterization SEM, EDX, with non-invasive testing is required to be carried out the determination of mechanical characteristics. The interest in this study is to analyze the influence of RE over elastic properties of these alloys in order to choose the best values appropriate with human bones, using Resonant Ultrasound Spectroscopy and ultrasound method.