Mg-Ag Alloys Research Articles

Revolutionizing Battery Longevity by Optimising Magnesium Alloy Anodes Performance

This research explores the enhancement of electrochemical performance in magnesium batteries by optimising magnesium alloy anodes, explicitly focusing on Mg-Al and Mg-Ag alloys. The study’s objective was to determine the impact of alloy composition on anode voltage stability and overall battery efficiency, particularly under extended cycling conditions. The research assessed the anodes’ voltage behaviour and internal resistance across magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) electrolyte formulations using a systematic setup involving cyclic voltammetry on the anode and electrochemical impedance spectroscopy. The Mg-Al alloy demonstrated superior performance, with minimal voltage drop and lower resistance increase than the Mg-Ag alloy. The results showed that the Mg-Al alloy maintained over 85% energy efficiency after 100 cycles, significantly outperforming the Mg-Ag alloy, which exhibited increased degradation and efficiency reduction to approximately 80%. These findings confirm that incorporating aluminium into magnesium anodes stabilises the anode voltage and enhances the overall battery efficiency by mitigating degradation mechanisms. Consequently, the Mg-Al alloy is identified as an up-and-coming candidate for use in advanced battery technologies, offering energy density and cycle life improvements. This study lays the groundwork for future research to refine magnesium alloy compositions further to boost battery performance.

On the shear strain associated with T1 precipitation in Al-Cu-Li(-Mg-Ag) alloys

The formation mechanism and the distribution arrangements of T1 precipitate plates in peak-aged samples of an Al-4Cu-1.2Li-0.3Mg-0.4Ag (wt.%) alloy are studied using atomic-resolution high-angle annular dark-field (HAADF) and annular bright-field (ABF) scanning transmission electron microscopy (STEM). The formation of a T1 plate of a single unit-cell thickness from the α-Al matrix is found to be associated with a large shear strain that is equivalent to the formation and glide of two different Shockley partial dislocations on two alternate {111}α planes. The T1 precipitate plates tend to cluster into various configurations, including T-shaped and V-shaped configurations comprising two plates of two different T1 variants, and X-shaped configurations consisting of three or four plates of two different variants. The signature of the shear strain is clearly visible in these configurations. A single T1 plate of one unit-cell thickness is elastically distorted in a T-shaped configuration, and the two T1 plates of the same variant in an X-shaped configuration are displaced with respect to each other. Different types of stair-rods are also formed in the intersection of the paired T1 plates in the V-shaped configurations.

More than the barrier effect: Biodegradable Mg-Ag alloy membranes for guided bone/tissue regeneration

Magnesium (Mg) and its alloys have emerged as promising candidates for guided bone/tissue regeneration (GBR/GTR) due to their good mechanical properties, biosafety, and biodegradability. In this study, we present a pioneering application of Mg-Ag alloys featuring tunable corrosion behaviors for GBR/GTR membranes, showcasing their in vitro antibacterial effects, cell migration, and osteogenic differentiation abilities. Mg-Ag alloys with different Ag contents were engineered to facilitate the cell migration of murine fibroblasts (L929) and the osteogenic differentiation of rat bone mesenchymal stem cells (rBMSCs). The Mg-Ag alloy consisted of recrystallized α-Mg grains and fine Mg4Ag second phases, with an observable refinement in the average grain size to 5.6 µm with increasing Ag content. Among the alloys, Mg-9Ag exhibited optimal mechanical strength and moderate plasticity (tensile yield strength of 205.7 MPa, elongation of 20.3%, and a maximum bending load of 437.2 N). Furthermore, the alloying of Ag accelerated the cathodic reaction of pure Mg, leading to a slightly increased corrosion rate of the Mg-Ag alloys while maintaining acceptable general corrosion. Notably, compared with pure Mg, Mg-Ag alloys had superior antibacterial effects against Porphyromonas gingivalis (P. gingivalis) and Staphylococcus aureus (S. aureus). Taken together, these results provide evidence for the significant clinical potential of Mg-Ag alloys as GBR/GTR membranes.

Effects of Zn, Nd, and Ca addition on the microstructure, mechanical and corrosion properties of biodegradable Mg-Ag alloys

In this study, casting, extrusion, biocorrosion and corrosive wear properties of 0.5 wt.% (Zn, Ca, and Nd) element added Mg-3%Ag alloys were investigated. As a result of the experimental studies, it was observed that the grains in the Zn and Ca added as-cast alloys became thinner, and thus the mechanical properties of the investigated alloys such as yield strength and hardness were improved. At the same time, the applied extrusion process provided an increase in the mechanical properties by refining the grain structure of the investigated alloys. As a result of in vitro tests, larger pitting was observed in as-cast alloys, while smaller and shallower corrosion pits were observed in extruded alloys. In the corrosive wear tests, the wear rate of extruded alloys generally showed a decreasing trend. However, the composition of both as-cast and extruded Mg-3% Ag-0.5%Zn-0.5% Ca was the alloy that exhibited the lowest value in terms of the wear rate.

Mechanical properties and in vitro biodegradation behavior of GASAR porous Mg-Ag alloy

In this thesis, porous pure Mg and Mg-3 wt%Ag alloys with oriented regular pore structures were prepared by the metal/gas eutectic unidirectional solidification method (GASAR process). The effects of the Ag content on the mechanical properties and early in vitro biodegradation behavior of porous Mg-Ag alloys were investigated. The results of compression experiments showed that Ag addition significantly enhanced the compressive strength and elastic modulus of the porous Mg-Ag alloy. Immersion experiments in SBF at 37℃ showed that although the Mg-3 wt%Ag alloy exhibited a faster corrosion reaction, the addition of Ag facilitated the precipitation of calcium and phosphorus salts, resulting in better osteoinductivity of the samples, which indicates its feasibility as a potential tissue engineering scaffold.

Influences of Extrusion and Silver Content on the Degradation of Mg-Ag Alloys In Vitro and In Vivo.

Binary magnesium-silver (Mg-Ag) alloys were designed as antibacterial materials for biomedical implant applications. In the present study, we focused on the effects of extrusion (extrusion ratio (ER): 1, 7.1, and 72.2) and Ag content (Ag = 0, 3, and 6 wt.%) on the degradation of Mg-Ag alloys in vitro and in vivo via microstructure characterization and corrosion/degradation measurements. The results showed that the Ag promoted a galvanic reaction with the Mg matrix to accelerate degradation or formed a protective oxide mesh texture to inhibit degradation, especially in vivo. Ag might also be beneficial for product crystallization, biomineralization, and organic matter deposition. For pure Mg, extrusion produced a more refined grain and decreased the degradation rate. For the Mg-Ag alloys, a low extrusion ratio (7.1) accelerated the degradation caused by the increase in the proportion of the precipitate. This promoted the release of Mg2+ and Ag+, which led to more deposition of organic matter and calcium phosphate, but also more H2 bubbles, which led to disturbance of product deposition in some local positions or even inflammatory reactions. Extrusion at a higher ratio (72.2) dissolved the precipitates. This resulted in moderate degradation rates and less gas production, which promoted osteogenesis without an obvious inflammation reaction.

Investigation of Microstructure, Mechanical and Corrosion Properties of Biodegradable Mg-Ag Alloys

Investigation of Microstructure, Mechanical and Corrosion Properties of Biodegradable Mg-Ag Alloys

Change in damping capacity arising from twin-boundary segregation in solid-solution magnesium alloys

ABSTRACT The change in twin-boundary mobility that is caused by twin-boundary segregation was investigated in pure magnesium and four binary solid-solution magnesium alloys (Mg-Ag, Mg-Sn, Mg-Y and Mg-Zn alloys). The damping capacity in the vicinity of {} twin boundaries was measured before and after annealing by nano-dynamic mechanical analysis. The subsequent annealing process led to a lower damping capacity in all magnesium binary alloys, which was in contrast to the results in pure magnesium. This is on account of the segregation of solute atoms in incoherent twin boundaries. The alloying elements, which have the characteristic of a low segregation energy for twin boundaries, effectively prevents the damping capacity degradation.

Mechanical Properties of Magnetron Sputtered Free Standing Mg-Ag Alloy Films

Magnesium based alloys gained great interest for medical biodegradable applications. Limitations arise from high corrosion rates and mechanical properties of the Mg based alloys. In recent work it was shown that the corrosion rate of a precipitate free Mg-6Ag thin film can be reduced by a factor of three compared to pure sputtered Mg. As Mg-6Ag combines the very promising corrosion results with a potential therapeutically use of Ag ions, the investigation of their mechanical properties is needed for a full characterization of Mg-Ag alloys as biodegradable material. In this work the Ag content was varied from 2 wt% to 10 wt%. The investigated thin film samples were dog-bone shaped samples with a thickness of 20 µm. The samples were fabricated by a combination of UV lithography, sacrificial layer technique and magnetron sputtering. The mechanical properties were determined using uniaxial tensile test. Compared to pure Mg samples fabricated by the same processing route the yield strength is approximately doubled for Ag containing samples. For films with a Ag concentration up to 8 wt% the elongation at fracture reaches a value of 7%. Further increase of the Ag concentration leads to lower elongation at fracture. Thus, especially due to the low corrosion rate, Mg-6Ag shows the optimum of all investigated alloys, with a yield strength of 310 MPa and an elongation at fracture of 6%.

The effect of osteoblasts on the surface oxidation processes of biodegradable Mg and Mg-Ag alloys studied by synchrotron IR microspectroscopy

High-resolution analytical methods, including synchrotron infrared microspectroscopy combined with wavelength-dispersive X-ray emission spectroscopy were applied to study the structure and chemical composition of the oxidized layer of pure and Ag-alloyed Mg exposed to cell culture media without and with osteoblasts. Comparative analysis has been done on pure Mg immersed in two different cell culture media: Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute medium (RPMI), whereas Mg-xAg binary alloys (x = 2, 4, 6, 8 wt%) were studied after immersion in DMEM. It is shown that the physicochemical formation of degradation products as well as the activity of the biological component is influenced by the addition of silver. It could be demonstrated that the presence of Ag in the Mg alloy enhances the chemical reaction between Mg and C to form amorphous and/or crystalline MgCO3 on account of CaCO3. As a consequence, the further available P and Ca react easily to form Mg-poor amorphous calcium phosphate phases. Osteoblasts actively adjusted these phases towards hydroxyapatite-like phases.

Anodic film growth and silver enrichment during anodizing of an Mg-0.6 at.% Ag alloy in fluoride-containing organic electrolytes

Binary Mg-Ag alloys are of interest as antibacterial biodegradable materials. In the present work, the behaviour of silver during galvanostatic anodizing of a sputtering-deposited Mg-0.6 at.% Ag alloy in a fluoride/glycerol electrolyte containing 5 or 60 vol.% water was investigated. Similar alloy compositions have been shown to have potential as biomaterials in in-vitro tests. The resultant barrier-type anodic films were examined using scanning and transmission electron microscopies, glow discharge optical emission spectroscopy and Rutherford backscattering spectroscopy. The films were shown to be nanocrystalline and to contain oxide and fluoride species, with O:F atomic ratios dependent on the amount of water in the electrolyte. Silver species were incorporated into the films, accompanied by loss of silver species to the electrolyte. Notably, silver was enriched in a ≤6 nm thick alloy layer, to concentration of at least 12 at.%.

Influence of the Microstructure and Silver Content on Degradation, Cytocompatibility, and Antibacterial Properties of Magnesium‐Silver Alloys In Vitro

Implantation is a frequent procedure in orthopedic surgery, particularly in the aging population. However, it possesses the risk of infection and biofilm formation at the surgical site. This can cause unnecessary suffering to patients and burden on the healthcare system. Pure Mg, as a promising metal for biodegradable orthopedic implants, exhibits some antibacterial effects due to the alkaline pH produced during degradation. However, this antibacterial effect may not be sufficient in a dynamic environment, for example, the human body. The aim of this study was to increase the antibacterial properties under harsh and dynamic conditions by alloying silver metal with pure Mg as much as possible. Meanwhile, the Mg-Ag alloys should not show obvious cytotoxicity to human primary osteoblasts. Therefore, we studied the influence of the microstructure and the silver content on the degradation behavior, cytocompatibility, and antibacterial properties of Mg-Ag alloys in vitro. The results indicated that a higher silver content can increase the degradation rate of Mg-Ag alloys. However, the degradation rate could be reduced by eliminating the precipitates in the Mg-Ag alloys via T4 treatment. By controlling the microstructure and increasing the silver content, Mg-Ag alloys obtained good antibacterial properties in harsh and dynamic conditions but had almost equivalent cytocompatibility to human primary osteoblasts as pure Mg.

Serrated flow in nanostructured binary Mg-Al alloys

Serrated flow, also known as the Portevin-Le Chatelier effect, has been extensively investigated in binary Mg-alloys such as Mg-Ag, Mg-Y and Mg-Li alloys. Interestingly, however, this effect has not been observed in Mg-Al alloys. In this work, we report the appearance of serrations in nanostructured Mg-Al alloys processed by cryomilling and spark-plasma-sintering during in-situ SEM microcompression tests at room temperature and strain rates between 2×10−3 and 10−1s−1. The observed serrated stress-strain behavior is attributed to the dynamic strain aging by which interstitial O and/or N impurities introduced during cryomilling diffuse and interact with in-grown dislocations during deformation.

Modified embedded-atom potential for B2-MgAg

Interatomic potentials for pure Ag and Mg–Ag alloy have been developed in the framework of the second nearest-neighbors modified embedded-atom method (MEAM). The validity and the transferability of the Ag potential were obtained by calculating physical, mechanical, thermal, and dislocation related properties. Since the {1 1 1}-generalized stacking fault energy curves obtained from first-principle calculations was used to develop the Ag potential, the critical resolved shear stress to move screw dislocations in Ag single crystal is in good agreement with the experimental data. By combining the ability of the potential to predict the surface energies with its accuracy in describing dislocation properties, the potential is thought to be a predictive model for analyzing the fracture properties of Ag. In addition, the performance of the potential was tested under dynamics conditions by predicting the melting temperature, where a good agreement with experimental value was found. The Ag-MEAM potential was then coupled to an existing Mg-MEAM potential to describe the properties of the binary system MgAg. While the heat of formation, the elastic constants, and the (1 1 0) γ-surface of the MgAg compound in the B2 phase were used to parameterize the potential, heat of formation for MgAg alloys with different stoichiometry, thermal properties of the B2-MgAg compound, as well as dislocation related properties in B2-MgAg compound were tested to validate the transferability of the potential. The heat of formation of Mg5Ag2, MgAg, and MgAg3, the elastic constants and the thermal properties of B2-MgAg obtained with the proposed potential align with first-principles and experimental data. In addition, the core structure of both 〈0 0 1〉 and 〈1 1 1〉 dislocations in {1 1 0} are in agreement with theoretical predictions, and the magnitudes of the critical resolved shear stress obtained at 0 K for both slip systems partially validate the slip behavior of B2-MgAg. Furthermore, the interaction between silver solute element and dislocations from the basal plane is correctly captured by the potential.

Qualitative and quantitative analysis during corrosion of biodegradable magnesium-silver wires

Event Abstract Back to Event Qualitative and quantitative analysis during corrosion of biodegradable magnesium-silver wires Petra Maier1*, Kelim V. Herrera2, Gabor Szakács3*, Carla Vogt2* and Norbert Hort3* 1 University of Applied Sciences Stralsund, School of Mechnaical Engineering, Germany 2 Institute of Inorganic Chemistry, Leibniz University Hannover, Germany 3 Helmholtz-Zentrum Geesthacht, Magnesium Innovation Center, Germany Magnesium wires have recently gained interest in the area of biodegradable metallic materials for biomedical application: either for pins, rods and clips for temporary fixation of bone fracture with a wire diameter in an mm range or for forming stents with much smaller diameters around a few 100 µm or less as fine wires. In this research a warm drawn Mg6Ag wire of a diameter of 1.6 mm has been investigated. Due to recrystallization during or after their complex forming processes, this wire shows a fine grained microstructure resulting in high strength and ductility. Binary Mg-Ag alloys are designed as antibacterial material to treat infections in an implant site and it has been indicated that Mg-Ag alloys have satisfactory corrosion properties under cell culture condition and much better mechanical properties than pure Mg. Focus of this study is not the remaining strength after corrosion or the corrosion morphology, but the analysis of the corroded wires and the corrosion products changing as the function of exposure time. Analysis included qualitative and quantitative SEM imaging with EDX, XRD, Raman, μ-XRF and IR spectroscopy and ICP-OES. The Mg6Ag wire of this study corrodes under forming Mg(OH)2, CaCO3 and AgCl showing strong weight loss and pitting corrosion. Keywords: in vitro, Implant, biomedical application, Biodegradable metal Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Anti-infective biomaterials Citation: Maier P, Herrera KV, Szakács G, Vogt C and Hort N (2016). Qualitative and quantitative analysis during corrosion of biodegradable magnesium-silver wires. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.01598 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. * Correspondence: Dr. Petra Maier, University of Applied Sciences Stralsund, School of Mechnaical Engineering, Stralsund, Germany, Email1 Dr. Gabor Szakács, Helmholtz-Zentrum Geesthacht, Magnesium Innovation Center, Geesthacht, Germany, gabor.szakacs@hzg.de Dr. Carla Vogt, Institute of Inorganic Chemistry, Leibniz University Hannover, Hannover, Germany, vogt@acc.uni-hannover.de Dr. Norbert Hort, Helmholtz-Zentrum Geesthacht, Magnesium Innovation Center, Geesthacht, Germany, norbert.hort@hzg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Petra Maier Kelim V Herrera Gabor Szakács Carla Vogt Norbert Hort Google Petra Maier Kelim V Herrera Gabor Szakács Carla Vogt Norbert Hort Google Scholar Petra Maier Kelim V Herrera Gabor Szakács Carla Vogt Norbert Hort PubMed Petra Maier Kelim V Herrera Gabor Szakács Carla Vogt Norbert Hort Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Antibacterial biodegradable Mg-Ag alloys

The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solution (T4) and aging (T6) heat treatment. The metallurgical analysis and phase identification showed that all alloys contained Mg4Ag as the dominant β phase. After heat treatment, the mechanical properties of all Mg-Ag alloys were significantly improved and the corrosion rate was also significantly reduced, due to presence of silver. Mg(OH)₂ and MgO present the main magnesium corrosion products, while AgCl was found as the corresponding primary silver corrosion product. Immersion tests, under cell culture conditions, demonstrated that the silver content did not significantly shift the pH and magnesium ion release. In vitro tests, with both primary osteoblasts and cell lines (MG63, RAW 264.7), revealed that Mg-Ag alloys show negligible cytotoxicity and sound cytocompatibility. Antibacterial assays, performed in a dynamic bioreactor system, proved that the alloys reduce the viability of two common pathogenic bacteria, Staphylococcus aureus (DSMZ 20231) and Staphylococcus epidermidis (DSMZ 3269), and the results showed that the killing rate of the alloys against tested bacteria exceeded 90%. In summary, biodegradable Mg-Ag alloys are cytocompatible materials with adjustable mechanical and corrosion properties and show promising antibacterial activity, which indicates their potential as antibacterial biodegradable implant materials.

Damage Tolerance Capability of an Al-Cu-Mg-Ag Alloy (2139)

The effects of dispersoid forming elements on the mechanical properties of Al-Cu- Mg-Ag alloys are examined. It is found that a small amount of Zr addition is detrimental to the damage tolerance of Al-Cu-Mg-Ag alloys in artificially aged temper, while Mn addition is beneficial. The superior damage tolerance capability of Alloy 2139 is demonstrated by comparing it to other high performance alloys used for DT critical applications

Effects of cold work on precipitation in Al-Cu-Mg-(Ag) and Al-Cu-Li-(Mg-Ag) alloys

A study has been made of the effects of cold work prior to aging on precipitation hardening in selected Al-Cu-Mg-(Ag) and Al-Cu-Li-(Mg-Ag) alloys. General aging characteristics have been determined by differential scanning calorimetry, and response to hardening has been correlated with microstructure using transmission electron microscopy (TEM), selected area electron dif-fraction (SAED), and quantitative stereology. Particular attention has been given to the phases Ω andT 1 that form on the {111 }α planes, although information on the precipitates θ′,S′ (orS), and δ′ is also reported. Although Ω andT 1, have similar morphologies and habit planes, their response to cold work prior to aging is different. Deformation promotesT 1 formation at the expense of the δ′ phase in Al-Cu-Li alloys and at the expense of δ′, θ′, andS′ in Al-Cu-Li-Mg-Ag alloys. On the other hand, in Al-Cu-Mg-Ag alloys, deformation assists precipitation of θ′ at the expense of Ω phase, and some decrease is recorded in the hardening response. Prior cold work is also found to reduce the response during natural aging in most alloys. These results are discussed in terms of the role of particular alloying additions.

The influence of the structure of cast Mg-Ag alloys on the structure of silver powders

The influence of the structure of cast Mg-Ag alloys on the structure of silver powders

Hybridization and screening effects in the MgKL1VAuger spectra of Mg-Ni, Mg-Cu, Mg-Zn, Mg-Pd, Mg-Ag, and Mg-Al alloys

Mg ${\mathrm{KL}}_{1}V$ Auger spectra from Mg-Ni, Mg-Cu, Mg-Zn, Mg-Pd, Mg-Ag, and Mg-Al alloys are presented. Mg-Ni, Mg-Cu, Mg-Pd, and Mg-Ag Auger spectra show peaks to high binding energy which increase in prominence with increasing transition- or noble-metal content and which arise from hybridization of the Mg $s$ and $p$ bands with $d$ bands of the other metals. The positions of these features are shown to be consistent with the positions of similar features in the ${L}_{2,3}V$ soft-x-ray emission spectra of corresponding Al alloys: This agrees with the prediction of the equivalentcores model that the local density of states around a core-ionized Mg atom should correspond to that around a neutral Al atom in the same environment. In Mg-Zn and Mg-Al alloys, $d$-band hybridization is not important and the high-binding-energy peaks in the Mg ${\mathrm{KL}}_{1}V$ spectra lose intensity with decreasing Mg content, as do the corresponding features in the Al ${L}_{2,3}V$ x-ray spectra observed from comparable Al alloys.