Silver Alloy Research Articles

Effect of silver and heat treatment on properties of 03Kh17N10M2 austenitic steel wire

The article examines the influence of various heat treatments, their temperature, as well as silver alloying on mechanical properties, phase composition and structure of steel wire from chromium-nickel-molybdenum austenitic stainless steel 03Kh17N10M2. Choice of the amount of silver alloying was based on previous studies of the antibacterial effect of modifying medical steels with silver. Since the antibacterial effect was confirmed on several bacterial strains, for the most efficient operation of alloys, it is necessary to determine the best temperature mode for working with them. Steel for the study was smelted and then transformed into wire through rolling, forging and drawing operations. On the obtained wire samples of different diameters with a silver content (0; 0.2 and 0.5 wt. %) mechanical tests were carried out to determine the elongation, yield strength and tensile strength. Various modes and temperatures of heat treatment were tested on wire of different diameters to study their effect on mechanical properties and structure. Microstructure of the wire samples subjected to heat treatment and obtained after drawing was investigated. A phase analysis was also carried out to determine the effect of silver in various quantities on austenitic steel. According to the results of the phase composition analysis, it was concluded that silver reduces the amount of gamma phase in steel, and this effect increases in proportion to the increase in silver amount. This change correlates with a slight drop in the metal ductility. At the same time, there are no significant changes in the strength characteristics and microstructure from the presence of silver.

Noninvasive µ-XRF Analysis of Ancient Silver Object

Abstract This case study details the noninvasive analysis of an 5000-year-old silver figurine from Iran, now in the collection of The Metropolitan Museum of Art. The The object of this study, a figure of a kneeling bull clothed in a robe with a stepped linear pattern and holding up a spouted vessel, is composed of 15 pieces of worked silver joined together with silver solder. The aim of the study is to apply noninvasive micro-xray fluorescence spectroscopy (μ-XRF) analysis to characterize the silver alloy compositions and compare the new data with previously obtained results from invasive chemical analyses of samples performed by thermal neutron activation.

Morphology, semiconductor properties, and chemical stability of AG(I) oxide anodically formed on silver and silver alloys

Morphology, semiconductor properties, and chemical stability of AG(I) oxide anodically formed on silver and silver alloys

SEM-FEG-EDS, GC-MS, EPR and Vibrational Spectroscopy Analysis of Materials in Baroque-Style Sculpture “Our Lady of Sorrows” from Garopaba, Santa Catarina, Brazil

Materials belonging to the polychromy and gilding of the sculpture ‘Our Lady of Sorrows, which belongs to the collection of a church in Garopaba, Santa Catarina, southern Brazil, were analyzed by multiple techniques. The analysis by μ-Raman and FTIR indicated the use of the ultramarine blue pigment, confirmed by EDS, with calcium carbonate observed in the base of preparation. The results show the use of gold leaf based on a gold and silver alloy, and the use of Armenian bole with clay and traces of manganese, as the base for fixing the gold leaf was characterized. GC-MS analysis suggested the use of plant oil in the painting process. Finally, the EPR analysis showed the presence of Fe3+, Mn2+ and organic radicals from the degradation of the binder, suggesting the formation of complexes with the degradation products, this being one of the first reports in this type of painting.

Facile green synthesis of highly stable, water dispersible carbohydrate conjugated Ag, Au and Ag-Au biocompatible nanoparticles: Catalytic and antimicrobial activity

Highly stable carbohydrate conjugated silver, gold and bimetallic silver-gold alloy biocompatible and nearly monodisperse nanoparticles (NPs) have been synthesized through bio-reduction of aqueous solution of corresponding metal salt precursors mediated by aqueous extracts of a high altitude lichen, Lobaria retigera. The biomolecule accountable for the reduction, stabilization and capping of the metal nanoparticles is identified to be carbohydrates. The as-synthesized carbohydrate conjugated nanoparticles have excellent dispersibilty in water, phosphate, phosphate-buffered saline, and serum media. The resulting nanoparticles were completely stable for several months in water. The nanoparticles were characterized using UV–visible spectroscopy, TEM, EDX, FT-IR, powder XRD, DLS and CV study. Though mostly spherical in shapes, occasionally truncated triangular and rod shapes were also noted. The average particle sizes of Ag, Au and Ag-Au alloy nanoparticles as determined from TEM analysis are 14.5 nm, 11.7 nm and 16.3 nm, respectively. Cyclic voltammetry pointed to a relatively high electrode potential barrier for the synthesized nanomaterials. The prepared Ag, Au and Ag-Au alloy nanoparticles served as efficient catalysts for the degradation of hazardous pollutant dye, methyl orange (MO) with rate constat of 0.1496 min−1, 0.1049 min−1, and 0.1882 min−1. The bimetallic Ag-Au nanoparticles exhibited the most accelerated reduction with 90.6% degradation efficiency. The reduction kinetics for the reactions followed a pseudo-first order, kAu < kAg< kAu-Ag. The Ag and Ag-Au alloy NPs showed pronounced antimicrobial activity towards selected bacterial strains while AuNPs lacked any such activity.

Studies and Considerations on Forty-Three Gold and Silver Nose Ornaments from the Moche Tomb of the Lady of Cao

The authors studied forty-three beautiful nose ornaments from the Moche tomb of the Lady of Cao, located in the north of Peru, which has been dated to be around 300–400 d.C. Of these items, thirty-nine are composed of a sheet of gold alloy joined together in various manners to a silver alloy sheet, which provides a strong contrast at their interface. Two nose ornaments are on gold alloy and two on silver alloy. These nose ornaments were studied using the following methods: (i) Energy-dispersive X-ray fluorescence (EDXRF); (ii) Transmission of monoenergetic X-rays (XRT) and (iii) X-ray Radiography (RAD). The conclusion, deduced from all applied methods, was that two sheets of gold and silver alloys were joined together with various methods, including gluing, mechanically joining, soldering, smelting with the aid of heating or using mercury to create an amalgam. It cannot be excluded that a few areas, visibly appearing as silver, were obtained by depletion silvering from the base Au-Cu-Ag alloy. By analyzing a fragment from the silver area of a nose ornament and by studying a few other nose ornaments from the tomb of the Lady of Cao in situ, G. Ingo and co-workers concluded that a unique sheet of three-component alloy (Ag-Cu-Au), whichemployed and transformed the surface of the objects to appear to be gold and silver by depletion gilding and silvering.

Microscopic X-ray fluorescence analyses (μ-XRF) of copper-based and silver alloy coins minted in Rhodes, Greece, from the fourth century BCE to the second century CE

The present study provides new data from the analysis of 111 copper-based and 11 silver-alloy coins from the ancient city of Rhodes, Greece. This is the first time that an elemental analysis has been carried out on copper-based coins issued by the Rhodian mint from the mid-4th c. BCE to the 2nd c. CE. Based on the μ-XRF results, three different groups of copper-based alloys are formed, with tin and lead as their major alloying components. The elemental composition shows that most of the coins are binary, leaded and ternary bronzes, while two samples—confirmed as imports—belong to a different technological tradition. All impurities present, such as iron, nickel, cobalt, antimony, or lead, are typical of copper ores, while the diminutive amounts of tin, lead and/or arsenic in some coins could indicate the use of alloys made from copper scrap. Based on a complex and extensive set of compositional data and using silhouette analysis for k-means clustering, we identified the existence of four distinct groups clustered on the basis of similar trace element values. The groups give indication to the raw materials used for minting and provided valuable insights into the technological and origin-related aspects of Rhodian coin production. In the silver coins, four groups of different silver grades can be identified on the basis of the most important alloying elements. Overall, the differences in the composition of the silver coins become clear, but a more extensive sample is needed to better understand the evolution of Rhodian silver coinage.

Optimizing Tin Electroplating for MEMS Meissner-Effect Transition-Edge Sensors

Electroforming metal features into patterned polymer molds targeting MEMS microfabrication allows for the enhancement of electrical, mechanical, magnetic, and thermal properties1. Uniform and repeatable electroforming processes are important to achieve the final desired metal geometry to optimize performance. MEMS fabrication processes typically rely on average plating rates based on historical depositions to determine future plating rates and offer the user options to vary electroplating time, among other options, to meet the desired device height(s). Process repeatability is often difficult to achieve in these scenarios and can be challenging in R&D applications with limited throughput. Inherent changes from one sample to the next can occur in many forms including a change in active area of lithographically patterned photoresist molds, resistance of substrates/seed layers below electroplated layers, geometry of the layout, chemistry make-up, electroplating setup, and fast deposition rates can all affect plating rates from sample to sample. Some changes can be controlled through careful inspection and tracking, then accounted for. However, some changes cannot be observed, and deposition rates can change from sample to sample leading to ever-changing plating rates.These challenges were encountered during electroplating of tin disks coupled with planar superconducting coils of niobium targeting the microfabrication of Meissner-Effect Transition-Edge Sensor devices (ME-TES)2. We investigated two and three electrode setups using a modified Dow Chemical Solderon make-up chemistry targeting pure tin depositions as opposed to tin and silver alloy depositions. Those changes were coupled with chronopotentiometry, chronoamperometry, and pulse plating experiments to optimize tin electrodeposition. Once found, the optimum tin deposition process was built into a graphical user interface (GUI)3 that predicts electroplating rates and was then successfully applied to microfabricate ME-TES’s. This process methodology could benefit other metal MEMS-based electrodeposition processes such as nickel, copper, gold, magnetic alloys, etc. to optimize electroplating.(1) Buchheit, T. E.; Christenson, T. R.; Schmale, D. T.; Lavan, D. A. Understanding and tailoring the mechanical properties of LIGA fabricated materials. Materials Science of Microelectromechanical Systems (Mems) Devices 1999, 546, 121-126. DOI: Doi 10.1557/Proc-546-121.(2) Finnegan, P. Packaging & Solid-state Materials and Fabrication Processes. In Packaging & Solid-state Materials and Fabrication Processes, June 2023.(3) St. John, C. In-Situ Analysis of Chronopotentiometry Data to Predict Electrodeposition Rates. In 243rd ECS Meeting with SOFC-XVIII, Boston, MA, 2023.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525 SAND2022-10288A

Comparison of the antibacterial properties of Mg, Mg-2Ag, and Ti intramedullary implants in a murine model of Staphylococcus aureus bacteremia -related periprosthetic osteomyelitis

Knowledge on the susceptibility of novel biomaterials to potential challenges in clinical practice is critical to defining the scope of implementation and further improvement of candidate materials. While periprosthetic infections remain a major and most difficult to treat complication in implantation orthopedics, magnesium-based biodegradable alloys are currently under eager attention as alternatives. Many in vitro studies reported profound antibacterial potential of pure magnesium and its alloys with improved bactericidal features. Some animal models with direct inoculation of bacteria or implantation of infected implants confirmed these results in vivo. However, the susceptibility of magnesium and binary alloys of magnesium and silver has not previously been assessed in experimental settings for hematogenous periprosthetic osteomyelitis. In the present study, we compared the antibacterial activity of pure Mg and Mg-2Ag with that of medical grade Titanium using a murine model for Staphylococcus aureus bacteremia –related peri-implant bone infection. The bacteria colonization was inhibited on surfaces of Mg and Mg-2Ag intramedullary implants. However, the bacteria load in surrounding tissue was found to be similar between the three materials. Current findings (i) indicate that biocidal efficacy of a material in vivo can be influenced by contamination route; (ii) aware of a limited antibacterial potential of unmodified magnesium and magnesium-silver implants for patients with elevated risks of bloodstream infections; and (iii) emphasize the need of further improvements/alloy modifications for particular clinical purposes.

Acoustic Studies of the Melting and Crystallization of Eutectic Gallium–Silver Alloys in Porous Glasses

Acoustic Studies of the Melting and Crystallization of Eutectic Gallium–Silver Alloys in Porous Glasses

Electron circular dichroism in hot electron emission from metallic nanohelix arrays.

We investigate the electron emission from 3D chiral silver alloy nanohelices initiated by femtosecond laser pulses with a central photon energy of hν = 1.65eV, well below the work function of the material. We find hot but thermally distributed electron spectra and a strong anisotropy in the electron yield with left- and right-circularly polarized light excitations, which invert in signbetween left- and right-handed helices. We analyze the kinetic energy distribution and discuss the role of effective temperatures. Measurements of the reflectance and simulations of the absorbance of the helices based on retarded field calculations are compared to the anisotropy in photoemission. We find a significant enhancement of the anisotropy in the electron emission in comparison to the optical absorption. Neither simple thermionic nor a multiphoton photoemission can explain the experimentally observed asymmetries. Single photon deep-UV photoemission from these helices together with a change of the work function suggests a contribution of the chirally induced spin selectivity effect to the observed asymmetries.

Prevention of urinary tract infection using a silver alloy hydrogel-coated catheter in critically ill patients: A single-center prospective randomized controlled study

BackgroundA new type of silver alloy hydrogel-coated (SAH) catheter has been shown to prevent bacterial adhesion and colonization by generating a microcurrent, and to block the retrograde infection pathway. However, these have only been confirmed in ordinary patients. This study aims to evaluate the effectiveness of a SAH catheter for preventing urinary tract infections in critically ill patients. MethodsThis was a prospective single-center, single-blind, randomized, controlled study. A total of 132 patients requiring indwelling catheterization in the intensive care unit (ICU) of the First Affiliated Hospital of the University of Science and Technology of China between October 2022 and February 2023 and who met the study inclusion/exclusion criteria were randomly divided into two groups. Patients in the SAH catheter group received a SAH catheter, while patients in the conventional catheter group received a conventional siliconized latex Foley catheter. The main outcome measure was the incidence of catheter-associated urinary tract infections (CAUTIs). Secondary outcome indicators included urine positivity for white blood cells and positive urine cultures on 3 days, 7 days, 10 days, and 14 days after catheterization, number of viable bacteria in the catheter biofilm on day 14, pathogenic characteristics of positive urine cultures, length of ICU stay, overall hospital stay, ICU mortality, and 28-day mortality. All the data were compared between the two groups. ResultsA total of 68 patients in the conventional catheter group and 64 patients in the SAH catheter group were included in the study. On day 7 after catheter placement, the positivity rate for urinary white blood cells was significantly higher in the conventional catheter group than in the SAH catheter group (33.8% vs. 15.6%, P=0.016). On day 10, the rates of positive urine cultures (27.9% vs. 10.9%, P=0.014) and CAUTIs (22.1% vs. 7.8%, P=0.023) were significantly higher in the conventional catheter group than in the SAH catheter group. On day 14, the numbers of viable bacteria isolated from the catheter tip ([3.21±1.91]×106 colony-forming units [cfu]/mL vs. [7.44±2.22]×104 cfu/mL, P <0.001), balloon segment ([7.30±1.99]×107 cfu/mL vs. [3.48±2.38]×105 cfu/mL, P <0.001), and tail section ([6.41±2.07]×105 cfu/mL vs. [8.50±1.46]×103 cfu/mL, P <0.001) were significantly higher in the conventional catheter group than in the SAH catheter group. The most common bacteria in the urine of patients in both groups were Escherichia coli (n=13) and Pseudomonas aeruginosa (n=6), with only one case of Candida in each group. There were no significant differences between the two groups in terms of ICU hospitalization time, total hospitalization time, ICU mortality, and 28-day mortality. ConclusionSAH catheters can effectively inhibit the formation of catheter-related bacterial biofilms in critically ill patients and reduce the incidence of CAUTIs, compared with conventional siliconized latex Foley catheters; however, regular replacement of the catheter is still necessary.

Activity of electrodeposited rhodium in acidic and basic water electrolysis

Hydrogen (H2) is increasingly seen as a future fuel and a potential alternative to fossil fuels, as it is the cleanest and ideal energy carrier. Water electrolysis is one of the easiest methods to produce H2, offering the advantage of simplicity. Rhodium (Rh) is considered one of the best electrocatalysts for water electrolysis. This research was conducted to investigate the activity of electrodeposited Rh for its potential electrocatalytic application in acidic and basic water electrolysis. The electrode was fabricated from a 5 g/L solution of rhodium sulfate [Rh2(SO4)3] electrodeposited at 3.0 V for 3 min in a 92.5% silver (Ag) alloy substrate. Electrochemical characterizations were performed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) in a three-electrode set-up. The acidic electrolyte was a sulfuric acid (H2SO4) solution while the basic electrolyte was a sodium hydroxide (NaOH) solution. Stability tests were done on a 48-h continuous run of water electrolysis. Results showed onset potentials of 1.4 V and −0.2 V for acidic oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively, while 0.6 V and −0.9 V for basic OER and HER, respectively. A consistent absolute value of limiting current, 8.00 × 10−3 A was observed for both reactions of the two electrolytes. Electrodeposited Rh as an anode showed excellent stability on both acidic and basic media but may fail as a cathode in long-term water electrolysis. The stability was observed to decrease with increasing electrolyte concentration at a higher rate on an acidic medium.

Acoustic Studies of the Melting and Crystallization of Eutectic Gallium–Silver Alloys in Porous Glasses

The paper presents the results of acoustic studies of the melting and crystallization of Ag–Ga alloys with a silver content of 1.5 and 3 at % embedded into porous glasses with an average pore size of 13 nm. The temperature dependences of the velocity of longitudinal ultrasonic waves are measured by a modified pulse-phase method at a frequency of 7 MHz in the 200–325 K range for complete and partial cooling–heating cycles. The temperature dependences of the ultrasonic velocity showed regions corresponding to phase transitions. Significant changes in the phase diagram of the bulk alloy due to nanostructuring have been revealed. It is shown that segregates with different crystal structures are formed in the pores for alloy of different compositions.

Synthesis of Bimetallic Silver and Copper Alloy Nanoparticles Embedded with Styrene-Methyl Methacrylate Copolymer Nanosphere (SMMA@Ag-Cu) as a Potential Surface Enhanced Raman Scattering (SERS) Substrate

Synthesis of Bimetallic Silver and Copper Alloy Nanoparticles Embedded with Styrene-Methyl Methacrylate Copolymer Nanosphere (SMMA@Ag-Cu) as a Potential Surface Enhanced Raman Scattering (SERS) Substrate

STUDY OF THE INFLUENCE OF SILVER ALLOYING ON THE MICROSTRUCTURE AND PROPERTIES OF MAGNESIUM ALLOY NZ30K FOR IMPLANTS IN OSTEOSYNTHESIS

Purpose. Study of the influence of silver alloying of magnesium alloy NZ30K on its mechanical properties for use in the manufacture of biodegradable implants. Research methods. The tensile strength and relative elongation of the samples were determined on a P5 tensile machine at room temperature. The microstructure of the samples was studied using a “Carl Zeiss” optical electron microscope using the “Observer.D1m” software. Samples were used after etching with a reagent containing 1 % nitric acid, 20 % acetic acid, 19 % distilled water, and 60 % ethylene glycol. Fractographic analysis of sample fractures was performed on a JSM-6360LA scanning electron microscope. The phase analysis of the structural components of magnesium alloys was studied using an electron microscope – a microanalyzer with an energy dispersive attachment РEMMA 202М and РЕМ 16I. Research on biocorrosion was carried out by keeping the samples in a solution of gelofusin – an artificial blood substitute for 2, 4, 6 weeks, using a TC-20 MICROmed thermostat. Results. The study showed that silver was a part of the complex alloyed intermetallic phases, which were additional crystallization centers. In this case, the average grain size decreases by almost three times compared to the original alloy. It was found that the optimal set of properties is achieved by the introduction of 0.1 % Ag, while the tensile strength increases by 7.9 % and the relative elongation almost doubles. It was found that the magnesium alloy with silver (0.1 %) slows down biocorrosion processes and helps to maintain a high level of tensile strength (σB = 205 MPa) after 6 weeks of exposure to a solution of helofusine. Thus, silver is a promising material for improving the structure and increasing the mechanical properties of biodegradable magnesium alloy implants. Scientific novelty. The silver content for alloying the NZ30K alloy was determined to be 0.1 % Ag, which forms the optimal ratio of strength and ductility, grain structure refinement, and slowing down biocorrosion processes. Practical value. NZ30K alloy with the addition of 0.1 % silver is promising for use in the manufacture of implants. The studied alloy provides the required level of properties until complete fracture consolidation.

Tuning the Activity of Silver Alloys for the Oxygen Reduction Reaction in Alkaline Media

Tuning the Activity of Silver Alloys for the Oxygen Reduction Reaction in Alkaline Media

A trade-off between mechanical strength and electrical conductivity of Al–Zn–Mg–Cu alloy via Ag alloying and retrogression re-aging heat treatment

The effects of silver (Ag) alloying and a retrogression re-aging heat treatment on the mechanical properties and electrical conductivity of the Al–Zn–Mg–Cu aluminum alloy were studied by means of tensile test, electrical conductivity test, and transmission electron microscopy (TEM). A trade-off between the mechanical strength and electrical conductivity was achieved, with the former reaching 558 MPa and the latter reaching 45.1 IACS. The alloy was prepared through a retrogression re-aging heat treatment (120 °C/6 h + 160 °C/7 h + 220 °C/0.5 h + 120 °C/24 h) performed on the solution and quenched samples. Furthermore, through TEM analysis of the sample solution treated at Temperature Ⅰ (420 °C/3 h + 470 °C/2 h) and Temperature II (420 °C/3 h + 480 °C/2 h), indicates that the Ag interacts with zinc or magnesium to form small clusters, which can act as precursors for η′ precipitates. η–type precipitates were the dominant precipitated phase, and the precipitation sequence was supersaturated solid solution (SSS)→ small clusters → Guinier–Preston (GP) zone → η′ → η. Furthermore, after the retrogression re-aging heat treatment, a large amount of GP (Ⅱ) and η′ precipitated in the matrix. GP (Ⅱ) and the η′ phase are related to the precipitation of {111} Al crystal plane, it is thus speculated that the interaction between the η′ phase and GP (Ⅱ) or nanosized Al3Zr dispersoids contributes to the strength of the alloy. Moreover, the retrogression re-aging heat treatment promotes the precipitation of the second phase, which can purify the matrix and reduce lattice distortion, thus improving the conductivity of the alloy.

Enkomi Cup: macrophotographic damage assessment

Macrophotographs of the Enkomi Cup have been examined to assess the cracking damage in the Cup metal, a silver alloy. The resulting interpretations and their implications indicate that the cracks are most probably due to long-term stress corrosion that stopped well before excavation and restoration. It is concluded that no additional restoration and conservation measures are needed.

Two-Step Synthesis of Large Gold–Silver Alloy Nanoparticles via the Combination of Seeded Growth and Citrate Co-reduction

We report a novel two-step method for the synthesis of uniform quasi-spherical and monodisperse gold–silver alloy nanoparticles with diameters of approximately 80 nm. In step one, gold–silver alloy seeds (G0) with diameters of approximately 30 nm are synthesized by citrate co-reduction of gold acetate and silver nitrate. In step two, the seeds grow into large alloy nanoparticles with diameters of approximately 80 nm by the combination of seeded growth and citrate co-reduction of gold and silver precursors. Our method makes use of gold acetate (rather than chloroauric acid) as a gold precursor to avoid the formation of silver chloride precipitates during synthesis. To our knowledge, we are the first to prepare gold–silver alloy nanoparticles with diameters of above 70 nm using gold acetate as a gold precursor. The alloy seeds and seed-grown nanoparticles show good control of size and composition, which enables tuning of the plasmonic band of these gold–silver alloy nanoparticles. Gold and silver are distributed uniformly within the cores of all Au-Ag alloy nanoparticles, while the surface is enriched in silver. This silver-enriched surface layer is thicker and more prominent for 25% Au alloy nanoparticles than for 50% and 75% Au alloy nanoparticles.