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In this work, the Ag@Cu particles with yolk–shell nanostructure was prepared by facile solvothermal method, which was modified on glassy carbon electrode (GCE) to fabricate electrochemical sensor for the convenient and fast determination of p-aminobenzoic acid (PABA). The surface morphology and electrochemical properties of the as-prepared Ag@Cu nanocomposite modified electrode were characterized by scanning electron microscopy, transmission electron microscopy, chronocoulometry, and electrochemical impedance spectroscopy. Further, the electrochemical sensing of PABA was performed on the Ag@Cu/GCE using cyclic voltammetry and differential pulse voltammetry techniques, showing high catalytic activity. Under the optimal conditions, the sensor exhibited a wide linear range, high sensitivity, and low detection limit of 0.315 μmol/L for PABA. The developed sensor was also successfully applied for PABA detection in anesthetic and cosmetics with satisfactory results. [ABSTRACT FROM AUTHOR]

The reliability of Sn-Ag-Cu (SAC) solder welded with Cu-organic solderability preservative (OSP) and NiAu- or NiPdAu-coated ball grid array (BGA) package pads has been investigated after isothermal aging. Moreover, the interfacial reaction and diffusion reaction are discussed. The intermetallic compound (IMC) layer was found to be too thick to withstand large stresses, leading to poor reliability of the solder joints on Cu-OSP pads. Additionally, for NiAu-coated pads, not only irregular Au-rich phases but also more diffused Ni without the barrier effect of Pd promoted formation of IMC in the solder balls, resulting in a potential mismatch with the initial solder. Compared with the NiAu-coated pad, the IMC layer that formed between the NiPdAu-coated pads and SAC105 solder was thinner, indicating an effective diffusion barrier effect of the Pd layer in the NiPdAu coating. Hence, SAC105 solder showed superior reliability on BGA package pads coated with NiPdAu. [ABSTRACT FROM AUTHOR]

Investigates the effects of sheath composition and rolling conditions on the microstructural development and superconducting properties of powder-in-tube Ag(Cu)-sheathed tapes. Chemical stability of the Ag(Cu) sheath regions during the partial melting process; Theoretical analysis of Cu[sub2]O precipitate formation and decomposition during thermal processing; Thermal schedule for partial melting.

The heterometallic Ag–Cu compounds easily assemble from the corresponding metal triflates and alkynes in the presence of tris(diphenylphosphanyl)methane (tppm) under basic conditions. The formation of two types of cluster skeletons – heptanuclear [Ag6Cu(C2R)3{HC(PPh2)3}2(CF3SO3)3](CF3SO3) {R = C6H4‐4‐X (X = CF3, 1A; OMe, 2A; NMe2, 3A; NC10H20O4, 4A); CPh2OH, 5A} and decanuclear [Ag6Cu4(C2C6H4‐4‐X)8{HC(PPh2)3}2](CF3SO3)2 (X = CF3, 1B; H, 6B) species is governed by the electronic properties of the alkynyl ligands and the ratio of the starting components. All of the complexes, except 4A, were structurally characterized by single‐crystal XRD analysis. The solid‐state photophysical studies reveal room‐temperature phosphorescence (Φem = 0.3–42.5 %, λem = 556–756 nm), which is dependent on the electron‐donating ability of the alkynyl fragments and the nature of the metal core. Moreover, the geometry of the cluster framework is substantially influenced by the bridging counterions that, together with electronic modulation of organic blocks, allow near‐IR emission. [ABSTRACT FROM AUTHOR]

Joining of graphite materials is problematic primarily due to the poor wettability of non-active filler metal on these materials. In an attempt to overcome this problem, magnetron sputtering deposition of Cr film on graphite was performed to modify the surface of the graphite. The wetting and brazing of graphite are carried out using non-active AgCu eutectic filler metals after deposition. The results indicated that surface modification enables wetting and joining of graphite with non-active filler. Cr film reacted with graphite forming Cr-C interfacial reaction layer, which resulted in the decrease of contact angle. Reliable graphite/graphite joints were obtained at temperature from 1113 K to 1233 K for 10 min. The typical interfacial microstructure of the brazed joint is graphite/Cr-C layer/Ag(s,s) + Cu(s,s) eutectic phase/Cr-C layer/graphite. The optimal shear strength of the joint was 13.6 MPa when the brazing parameters were 1173 K for 10 min. [ABSTRACT FROM AUTHOR]

Within the last years, research in the areas of hygiene and healthcare has focused on the resurgence of antimicrobial coatings to prevent infections and control their spreading. We used a physical vapor deposition technology to deposit coatings of either silver or copper individually or as mixtures on flexible polymeric substrates. Five combinations of silver and copper coatings were produced with a thickness of 50 nm. The respective amounts of silver and copper on the coated surfaces were determined using scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDX). The antimicrobial characteristics of silver and copper against Escherichia coli K12 ( E. coli ) were investigated, focusing on the possible synergistic effects of the two metals. The deposited coatings showed homogeneous mixtures of silver and copper clusters. The mixtures of silver and copper as well as pure silver showed antimicrobial properties. In contrast, pure copper did not exhibit antimicrobial effects. The dissolution behavior of copper and silver was determined by incubation of mixed layers in physiological media (synthetic sweat). Copper coatings proofed to be fully dissolvable whereas silver showed lower solubility. With increasing copper content in the mixed coatings, the dissolution of silver increased as well. The observed dissolution behavior was correlated to the results of the antimicrobial activity of the investigated coatings. [ABSTRACT FROM AUTHOR]

In this work, a new technique process for processing Cu-Zn mixed ores containing chalcopyrite and marmatite was proposed to avoid the complex Cu-Zn flotation and extraction separation processes, as well as for the comprehensive utilization of abandoned silver-containing zinc leaching residue (ZLR). In the first step, stepwise bioleaching of Cu-Zn mixed ores in the presence of mixed moderately thermophilic microorganisms and Fe 3 + was conducted for recovering Zn from marmatite. Copper was then efficiently extracted from the copper-containing bioleaching residues through catalytic bioleaching by using ZLR as catalyst. The final bioleaching residues were subsequently leached by thiourea for recovering Ag efficiently. The provided technique process accomplished the stepwise dissolution of Cu-Zn mixed ores and the comprehensive utilization of silver-bearing ZLR. The intermediate species, the electrochemical dissolution process and the electrochemical interactions between chalcopyrite and marmatite were also discussed to interpret the detailed mechanisms of stepwise bioleaching. [ABSTRACT FROM AUTHOR]

Understanding the thermal evolution mechanisms of metal nanoparticles (NPs) at the quantum-dot-scale is arrestive and meaningful for utilization of nanomaterials. Herein, an interesting fusion evolution phenomenon of Ag-Cu NPs induced by in-situ TEM high-energy electron beam illumination has been observed and investigated. It turned out that a rapid fusion process was in progress as reflected by the significant morphological change as the electron beam illumination time increased. The Ag-Cu NPs clusters tended to shrink their overall surface area along with the increase of sintering neck radii and decrease of neck curvature which was dominated by lattice diffusion mechanism. In addition, the necks among three Ag-Cu NPs continuously grew until the three particles became a short nanorod with a relatively uniform lateral diameter of about 20 nm after 300 sʹ illumination. It was also worthy of note that the smaller particles disappeared faster than bigger ones due to their highest surface energy. [ABSTRACT FROM AUTHOR]

The paper focuses on the development and characterization of bionanocomposite films based on fish skin gelatin (FSG) and bimetallic Ag-Cu nanoparticles (Ag-Cu NPs). Effects of Ag-Cu NPs loadings on the thermal, mechanical, rheological, structural, and antibacterial properties of the gelatin-based films were investigated. An increase in tensile strength (TS), and a decrease in elongation at break (EAB) recorded while nanocomposite (NC) films were loaded with 2% (w/w) NPs. Nevertheless, both parameters (TS and EAB) dropped drastically with further addition of NPs ( p < 0.05). Oscillatory rheological data also established that 2% NPs loading improved the mechanical property of the FSG/Ag-Cu nanocomposites. The NC films showed lower transparency, yellowness, and the total color difference over the control FSG film ( p < 0.05), whereas the UV barrier property improved substantially. An interaction between NPs and gelatin matrix in the film was evidenced through Fourier transform infrared (FTIR) spectroscopy. Both differential scanning calorimetric (DSC) and thermogravimetric (TGA) analyses confirmed the incorporation of NPs significantly improved the glass transition temperature ( T g ), and thermal stability of the NC films. X-ray diffraction (XRD) demonstrated a change in the crystallinity of FSG films with incorporation of NPs. However, the NC films became coarse with added NPs as indicated by scanning electron microscopy (SEM) micrographs. The NC films exhibited a strong antibacterial activity against both Gram-positive and Gram-negative bacteria. Overall, the NC films could be used as an active food packaging materials for food preservation by controlling foodborne pathogens and spoilage bacteria. [ABSTRACT FROM AUTHOR]

Plasticized polylactic acid (PLA) based nanocomposite films were prepared by incorporating polyethylene glycol (PEG) and two selected nanoparticles (NPs) [silver–copper (Ag–Cu) alloy (<100 nm) and zinc oxide (ZnO) (<50 and <100 nm)] through solvent casting method. Incorporation of Ag–Cu alloy into the PLA/PEG matrix increased the glass transition temperature ( T g ) significantly. The crystallinity of the nanocomposites (NCs) was significantly influenced by NP incorporation as evidenced from differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. The PLA nanocomposite reinforced with NPs exhibited much higher tensile strength than that of PLA/PEG blend. Melt rheology of NCs exhibited a shear-thinning behavior. The mechanical property drastically reduced with a loading of NPs, which is associated with degradation of PLA. SEM micrographs exhibited that both Ag–Cu alloy and ZnO NPs were dispersed well in the PLA film matrix. [ABSTRACT FROM AUTHOR]

In this study, Ag-Cu nano-particles (NPs) with face-centered cubic crystal structure have been synthesized through a facile one-step approach. The statistical design of experiment has been employed to optimize the process parameters and find significant factors that affect the particle size of Ag-Cu NPs. Results showed that the reaction temperature, reaction time, and binary interaction of them have played a significant role in affecting the particle size. The increase in reaction time drove the particle size to increase heavily under the high level of reaction temperature. Furthermore, a mathematical model of particle size corresponding to factors was obtained by analysis of variance and regression fitting. Repetitive experimental verification showed that the average size of Ag-Cu NPs could be controlled within 10-15 nm under the optimal combination of 0 °C of reaction temperature, 5 min of reaction time, 2 of the molar ratio of Ag/Cu, 4 of the molar ratio of reductant/precursors, and 1000 rpm of stirring speed. Lower temperature can result in high nucleation rate and prevent the further growth of Ag-Cu NPs as well. This study provides a new thought and guidance for the synthesis of bimetallic NPs. [ABSTRACT FROM AUTHOR]

We present a new methodology to create colorful textile antennas that can be embroidered within logos or other aesthetic shapes. Conductive threads (e-threads) have already been used in former embroidery unicolor approaches as attributed to the corresponding conductive material, viz. silver or copper. But so far, they have not been adapted to 'print' colorful textile antennas. For the first time, we propose an approach to create colorful electronic textile shapes. In brief, the embroidery process uses an e-thread in the bobbin case of the sewing machine to embroider the antenna on the back side of the garment. Concurrently, a colorful assistant yarn is threaded through the embroidery needle of the embroidery machine and used to secure or 'couch' the e-threads onto the fabric. In doing so, a colorful shape is generated on the front side of the garment. The proposed antennas can be unobtrusively integrated into clothing or other accessories for a wide range of applications (e.g., wireless communications, Radio Frequency IDentification, sensing). [ABSTRACT FROM AUTHOR]

Silver(I) and copper(II) complexes of 4-amino-N-(4,6-dimethyl-2-pyrimidinyl) benzenesulfonamide (smz) have been synthesized and characterized by elemental analysis and infrared (IR),1H NMR, and UV–vis spectroscopy. [Ag(smz)(pyridine)] (1) crystallizes in monoclinic system with space groupP21/candZ = 4, while [Cu(smz)2(pyridine)2]·H2O (2) crystallizes in triclinic system with space groupP-1andZ = 2. X-ray analysis revealed that silver in1is four-coordinate exhibiting distorted tetrahedral geometry, while copper in2is coordinated to six nitrogens leading to a highly distorted octahedral geometry. The molecular structures of both1and2are stabilized by N–H⋯O and C–H⋯πintermolecular and C–H⋯O intramolecular interactions. Water plays a significant role in crystal packing by forming strong N–H⋯Owaterintramolecular as well as Owater–H⋯N intermolecular interactions in2. The results of IR, UV–vis,1H NMR spectral data and thermal analysis for1and2suggest that the binding of silver and copper to the sulfonamidic nitrogen is in agreement with the crystal structure determination. Antimicrobial activities of silver (1) and copper (2) complexes of sulfamethazine are studied by the dilution method againstStaphylococcus aureusandEscherichia colistrains. Two new transition metal (Ag and Cu) complexes of sulfamethazine with different stoichiometries and coordination environments are synthesized, characterized, and tested as antimicrobial agents. [ABSTRACT FROM AUTHOR]

The microstructure and bonding strength of vacuum-brazed C/C composite and C/C composite with inactive AgCu foil are studied. The interface structure of the brazed joint consists of the TC4/Ti 2 Cu+Ti(ss)/Ti 2 Cu/TiCu/Ag(ss)+Ti 3 Cu 4 /TiC/C/C composites. The maximum shear strength of the joint is 33 MPa at 880 °C for 10 min and Ti diffusing from TC4 into the filler improves the wettability on the C/C composite. The interface evolution during the brazing process and associated mechanism are discussed. [ABSTRACT FROM AUTHOR]

The paper is devoted to the investigation of the thermodynamic properties of Ag - 28% Cu powders processed by mechanical alloying route at two different milling times (20 and 80 h). Thermodynamic properties represented by the heat capacity ( C p ) and the enthalpy increment ( H T − H 298 ) have been obtained in the temperature range from ambient to 1073 K by drop calorimetry using a multi-detector high temperature calorimeter SETARAM MHTC-96. A critical comparison of the isothermal enthalpy measurements with the dynamic differential scanning calorimetric (DSC) results has been made to reveal the occurrence of the micro-relaxation process, as well as of the correlative effects of decomposition and growth processes. New features related to the effect of the milling time and crystallite size on the thermal behavior and energetic parameters were evidenced. The correlation between thermal stability and microstructure of the sample obtained after 80 h processing has been investigated by the evaluation of the in situ controlled annealing powder X-ray diffraction patterns (XRD). [ABSTRACT FROM AUTHOR]

Solar cells devices based on inorganic/polymer heterojunction can be a possible solution to harvest solar energy and convert to electric energy with high efficiency through a cost-effective fabrication. The solution-process method can be easily used to produce large area devices. Moreover, due to the intrinsic different charge separation, diffusion or recombination in various semiconductors, the interfaces between each component may strongly influence the inorganic/polymer heterojunction performance. Here we prepared a n-type Ag 3 CuS 2 (Eg = 1.25 eV) nanostructured film through a room-temperature element reaction process, which was confirmed as direct bandgap semiconductor through density function theory simulation. This Ag 3 CuS 2 film was spin-coated with an organic semiconducting poly(3-hexythiophene) (P3HT) or polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) film, which formed an inorganic/polymer heterojunction. After constructing it to a solar cell device, the power conversion efficiencies of 0.79% and 0.31% were achieved with simulated solar illumination on Ag 3 CuS 2 /P3HT and Ag 3 CuS 2 /PTB7, respectively. A possible mechanism was discussed and we showed the charge separation at interface of inorganic and polymer semiconductors played an important role. [ABSTRACT FROM AUTHOR]

We report a novel promising semiconductor of Ag3CuS2 serving as absorber material in inorganic–organic solid-state solar cells for the first time, and the device (ITO/ZnO/Ag3CuS2/P3HT/Pt) exhibits a power conversion efficiency of 2.01%. This study opens up an available method to develop various ternary absorber materials for tertiary generation solar cells. [ABSTRACT FROM AUTHOR]

The effect of braze interlayer thickness on the strength of alumina brazed with silver-copper oxide reactive air braze (RAB) alloys was evaluated using a four point bend test configuration. The brazed samples had an average fracture strength of 180 MPa or approximately 60% of the average monolithic alumina strength. The joint strength values obtained exceeded the yield strength and ultimate tensile strength of the silver interlayer indicating strong ceramic to metal adhesion and the development of a triaxial stress state in the braze interlayer. The average fracture strength was relatively constant (190 ± 60 MPa) in the thickness range of 0.030-0.230 mm for all test conditions. The braze fracture strength then decreased to 100 ± 30 MPa as the braze thickness increased from 0.230 to 0.430 mm indicating a loss of triaxial constraint with increasing interlayer thickness. In addition, four different fracture modes were observed. [ABSTRACT FROM AUTHOR]

Abstract: An investigation has been carried out for arsenic removal from a silver–copper ore. The copper ore was roasted in air, in nitrogen atmosphere and in vacuum at high temperature. It was found that arsenic was more easily removed in vacuum at lower temperature with shorter time. By suitably adjusting the main reaction conditions, almost 98.97% arsenic could be removed, while most of the sulfur was particularly retained in the copper ore. It was illustrated that arsenic could be completely removed on anaerobic conditions. After arsenic was removed, the copper ore with higher economic value could be used for feeding to the smelter. [Copyright &y& Elsevier]

Abstract: This anthracological study of fuel wood used in the Faravel mines is part of a doctorate research programme conducted on the interrelationship between mines and forests of the Southern Alps during the Middle Ages. The study area is situated in the upper Durance valley, a major mining region from the 11th to the end of the 13th century. Man sought and extracted silver-bearing ore from the valley bottoms to the summit of the mountains. He employed firesetting to attack the hard gneiss bedrock. The study of residual charcoal has been used to measure the impact of the mining economy on the development of mountain forests. The example of the small district of Faravel situated in an upper mountainous region (1900–2150 m altitude), illustrates a supply anchored at subalpine level with a gradual extension of the source area towards the timberline. The anthracological spectra document extinction of Pinus cembra L. at subalpine level and the lowering of the upper limit of the dense forest dominated by Larix decidua Mill. These changes are the result of agropastoral and mining pressure, as testified by both surviving manuscripts and archaeology. [Copyright &y& Elsevier]

Spectral properties of silver-copper phthalocyanine (CuPc) nanocomposites prepared by thermal vacuum evaporation were studied. The samples differed from each other in the number of silver nanolayers and the thickness of intervening CuPc films. A long-wavelength shift of the surface plasmon resonance absorption band maximum and enhancement of the optical density per unit thickness of these films were observed as the thickness of the CuPc films decreased from 20 to 10 nm. This effect could be explained by the fact that the local field was stronger throughout practically the whole thickness of the thinner CuPc films due to contributions of both granular Ag nanolayers neighboring the CuPc film. [ABSTRACT FROM AUTHOR]

Abstract: Petrogeochemical investigations at the Sahlabad region have revealed that epigenetic listvenite veins occur in sheared zones of metaophiolitic suites of Cretaceous age. The listvenite mineralization developed in three forms, namely (1) the silica-listvenite veins which are chiefly composed of chalcedony, opal, quartz, pyrite, chalcopyrite, serpentine and relicts of chrome spinels, magnetite and fuchsite; (2) the carbonate listvenite veins which are comprised principally of magnesite, dolomite, calcite, siderite, pyrite, chalcopyrite, serpentine and relicts of fuchsite, chrome spinels and magnetite; and (3) the silica-carbonate listvenite veins which include opal, quartz, dolomite, magnesite, pyrite, chalcopyrite, serpentine and relicts of chrome spinels and magnetite. The absence of mineralized granitoids and the frequent occurrences of clearcut non-metamorphosed veins indicate that the mineralizing fluids were rich in CO2, H2O, H2S and H4SiO4 and possibly formed as a result of metamorphic dehydration and decarbonation reactions of the oceanic crust at the amphibolite–greenschist facies. Geochemically, the listvenites are enriched in SiO2, MgO, CaO, CO2, LOI, Cr, Ni, Co, Au, Cu, Ag, Hg, and Pt. Also, the veins contain high values of LOI, indicating the H2O–CO2-rich metamorphogenic fluids. The high Cr content and detectable values of K2O, Al2O3 and Na2O in the listvenite veins possibly indicate the presence of fuchsite and chrome spinels. The geochemical signatures attest that the hydrothermal fluids probably derived from a metamorphosed ultramafic protolith. The maximum values for gold, copper, mercury and silver in the listvenites are about 1.9ppm, 5.4 %, 8ppm and 6.5ppm, respectively and provide a unique exploration guide for further gossan sampling, remote sensing mapping, isotopic and fluid inclusion studies in the Iranian metaophiolites. [Copyright &y& Elsevier]

Thin films of Ag2Cu2O3 were formed on glass substrates by RF magnetron sputtering technique under different oxygen partial pressures in the range 5 × 10-3 - 8 × 10-2 Pa using mosaic target of Ag70Cu30. The influence of oxygen partial pressure on the core level binding energies, crystallographic structure, and electrical and optical properties of the deposited films was studied. The atomic ratio of copper to silver in the films was 0.302. The oxygen content was in correlation with the oxygen partial pressure maintained during the growth of the films. The films formed at oxygen partial pressures < 2 × 10-2 Pa was mixed phase of Ag2Cu2O3 and Ag. The films deposited at 2 × 10-2 Pa were single phase of Ag2Cu2O3. The crystallite size of the films formed at 2 × 10-2 Pa was 12 nm, while those films annealed at 473 K was 16 nm. The nanocrystalline Ag2Cu2O3 films formed at oxygen partial pressure of 2 × 10-2 Pa showed electrical resistivity of 8.2 Ωcm and optical band gap of 1.95 eV. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Abstract: The Ag–CuO x system is being investigated as potential filler metals for use in air brazing high temperature electrochemical devices such as solid oxide fuel cells and gas concentrators. The current study examines the effects of palladium addition on the high temperature joint strength of specimens prepared from yttria stabilized zirconia (YSZ) bars brazed with the binary Ag–CuO x , and 15Pd–Ag–CuO. It was found that while the binary Ag–CuO x system exhibits stronger room temperature strength than the 15Pd system the strength is reduced to values equivalent of the 15Pd system at 800 °C. The 15Pd system exhibits a lower ambient temperature strength that is retained at 800 °C. In both systems the failure mechanism at high temperature appears to be peeling of the noble metal component from the oxide phases and tearing through the noble metal phase whereas sufficient adhesion is retained at lower temperatures to cause fracture of the YSZ substrate. [Copyright &y& Elsevier]

We report on the performance characteristics of GaN-based light-emitting diodes (LEDs) fabricated with Ag-alloy p-type reflectors including AgNi, AgCu, and AgAl. Compared to the reference LEDs fabricated with Ag, LEDs fabricated with AgNi and AgCu produced smaller forward voltages and higher light output power. Under optimized thermal annealing conditions, the forward voltages obtained were 3.56, 3.29, 3.28, and 3.44 V, the light output powers were 14.38, 15.73, 14.40, and 12.77 mW, and the power efficiencies were 20.2%, 23.91%, 21.95%, and 18.45% for LEDs fabricated with Ag, AgNi, AgCu, and AgAl, respectively. The surface morphology of Ag-alloy was also found to be smoother than that of Ag, suggesting that Ag-alloy reflectors, particularly AgNi, are very promising for practical applications. [ABSTRACT FROM AUTHOR]

Abstract: The increasing demand for portable electronics has led to the shrinking in size of electronic components and solder joint dimensions. The industry also made a transition towards the adoption of lead-free solder alloys, commonly based around the Sn–Ag–Cu alloys. As knowledge of the processes and operational reliability of these lead-free solder joints (used especially in advanced packages) is limited, it has become a major concern to characterise the mechanical performance of these interconnects amid the greater push for greener electronics by the European Union. In this study, bulk solder tensile tests were performed to characterise the mechanical properties of SAC 105 (Sn–1%wt Ag–0.5%wt Cu) and SAC 405 (Sn–4%wt Ag–0.5%wt Cu) at strain rates ranging from 0.0088s−1 to 57.0s−1. Solder joint array shear and tensile tests were also conducted on wafer-level chip scale package (WLCSP) specimens of different solder alloy materials under two test rates of 0.5mm/s (2.27 s−1) and 5mm/s (22.73 s−1). These WLCSP packages have an array of 12×12 solder bumps (300μm in diameter); and double redistribution layers with a Ti/Cu/Ni/Au under-bump metallurgy (UBM) as their silicon-based interface structure. The bulk solder tensile tests show that Sn–Ag–Cu alloys exhibit higher mechanical strength (yield stress and ultimate tensile strength) with increasing strain rate. A rate-dependent model of yield stress and ultimate tensile strength (UTS) was developed based on the test results. Good mechanical performance of package pull-tests at high strain rates is often correlated to a higher percentage of bulk solder failures than interface failures in solder joints. The solder joint array tests show that for higher test rates and Ag content, there are less bulk solder failures and more interface failures. Correspondingly, the average solder joint strength, peak load and ductility also decrease under higher test rate and Ag content. The solder joint results relate closely to the higher rate sensitivity of SAC 405 in gaining material strength which might prove detrimental to solder joint interfaces that are less rate sensitive. In addition, specimens under shear yielded more bulk solder failures, higher average solder joint strength and ductility than specimens under tension. [Copyright &y& Elsevier]

We have developed a Cu−Ag-based mixed metal conductive ink from which highly conductive tracks form on a flexible substrate after annealing at low temperature. Addition of small Ag particles significantly improves the particle packing density by filling the interstices formed between the larger Cu particles, which in turn facilitates better conductivity compared to pure Cu metal film. The particle size and volume ratio of the Ag particles added should be carefully controlled to achieve maximum packing density in the bimodal particle system, which is consistent with the theoretical considerations of the Furnas model. In addition, we demonstrate direct writing of complex patterns that exhibit high conductivity upon annealing at sufficiently low temperature (175−210 °C) to not damage the transparent plastic substrate such as polyethersulphone (PES). [ABSTRACT FROM AUTHOR]

The phase diagram of the Ag-Ni binary system has been evaluated by using the calculation of phase diagrams (CALPHAD) method based on experimental data of the phase equilibria and thermodynamic properties. Gibbs free energies of the liquid and fcc phases were described by the subregular solution model with the Redlich-Kister equation. On the basis of the thermodynamic parameters of the Ag-Ni, Ag-Cu, and Cu-Ni systems, and experimental information of the phase equilibria in the Ag-Cu-Ni system, the thermodynamic assessment in the Ag-Cu-Ni system was carried out. The calculated results in both the Ag-Ni and Ag-Cu-Ni systems are in reasonable agreement with experimental data. [ABSTRACT FROM AUTHOR]

Abstract: As a means of increasing the use temperature of ceramic–ceramic and ceramic–metal air brazes, palladium was investigated as possible ternary addition to the currently employed silver–copper oxide system. The silver component was directly substituted with palladium to form the following series of alloys: (100− y)[(100− z)Pd−(z)Ag]−(y)CuO x where y =0–34mol% CuO x and z =50–100mol% silver and where x =0, 0.5, or 1, respectively, denotes copper metal, Cu2O, or CuO. From differential thermal analysis, it was determined that the addition of palladium causes an increase in the solidus and liquidus temperatures of the resulting Pd–Ag–CuO brazes. In general, the liquidus was found to increase by approximately 220°C for the (100− y)(25Pd−75Ag)−(z)CuO x filler metal compositions relative to comparable Ag–CuO x alloys. Likewise, the solidus was found to increase for these alloys, respectively, by 185 and 60°C, respectively, for CuO x contents of y =0–1mol% and 4–10mol%. For the (100− y)(50Pd−50Ag)−(y)CuO x alloys, the solidus increased between 280 and 390°C over a copper oxide compositional range of x =0–8mol%. It was determined from sessile drop experiments conducted on alumina substrates that in all cases the palladium causes an increase in the wetting angle relative to the corresponding binary braze. Alloy compositions of (100− y)(25Pd−75Ag)−(y)CuO x displayed increased wetting angles of 5–20° relative to comparable binary compositions. (100− y)(50Pd−50Ag)−(y)CuO x alloys exhibited an increase in contact angle of 10–60° and compositions containing less than 10mol% CuO x were not able to wet the substrate. Metallographic analysis indicated that the microstructure of the braze consists of discrete CuO x precipitates in an alloyed silver–palladium matrix. In both the binary and ternary filler metal formulations, a reaction layer consisting of CuAlO2 was observed along the interface with the alumina substrate. This reaction product appears to be beneficial in promoting wetting by the remaining braze filler metal. However the formation of this layer is hindered as the concentration of palladium in the filler metal is increased, which appears to be the primary cause of poor wettability in these compositions, as indicated by the substantial amount of porosity found along the braze/substrate interface. [Copyright &y& Elsevier]

Cu–Ag filamentary microcomposites with various Ag contents, alloying additions and ingot annealing processes were prepared by vacuum casting and cold drawing. The strength and conductivity were measured at different drawing strain degrees. High conductivity tends to connect to low strength for the microcomposites with different Ag content, alloying addition and annealing process. Increasing Ag concentration, adding constituents Zr and Cr, or using low ingot annealing temperature can improve the strength but impair the conductivity. Alloying additions or ingot annealing processes affect the relationships between the strength and conductivity more significantly than that of Ag concentration. The strengthening benefit is mainly from interface obstacle and dispersive precipitation while conducting loss is mainly from lattice distortion and interface scattering. An approximate expression to predict the relationships between the strength and conductivity is deduced from the interface strengthening and scattering model. [ABSTRACT FROM AUTHOR]

We have studied the reactions between supercritical isopropanol and salts of various elements (silver, copper, gold, zinc, iron, nickel, cobalt, manganese, europium, ruthenium, antimony, bismuth, and tellurium) infiltrated into opal photonic crystals. According to transmission electron microscopy data, the diameter of the SiO2 spheres in the opal crystals is 260 nm, and the nanoparticles of the metals and incomplete reduction products range in size from 2 to 80 nm, i.e., are no greater in size than the opal pores. [ABSTRACT FROM AUTHOR]

Abstract: Tensile characteristics of Ag-4.4wt% Cu specimens of different grain diameters were investigated at 300, 343, 383, 423 and 463K. It was found that the strain hardening exponent n, resilience U y and strain rate were increased with increasing grain diameter while a decrease in the yield stress , fracture stress and toughness U f were observed. This was explained in view of the dislocation interaction with the defects and different inclusions in the matrix and the formation of twins. The formation of twins was found accompanied by an abrupt increase in the strain per unit stress () at a critical stress . The value of was found to decrease with the increase of grain diameter d. Concentration of the deformation twins was also found to decrease with increasing the grain diameter d. The associated atomic rearrangement during the formation of deformation twins was found thermally activated by activation energy of ∼0.2eV. The microstructure of Ag-4.4wt% Cu alloy specimens was performed by optical microscopy. [Copyright &y& Elsevier]

We report on the formation of alloy nanoclusters in silica by Ag/Cu ion sequential implantation. The formation of alloy nanocluster has been evidenced by optical absorption spectra, selected area electron diffraction and energy dispersive X-ray spectra. The microstructure characters of nanoclusters have been studied by high resolution transmission electron microscopy. The lattice distortion of some nanoclusters has been observed. A model has been given to explain the distortion. Some defects (partial dislocation, stacking faults) have been found in nanoclusters. [Copyright &y& Elsevier]

Reports on the room-temperature synthesis and structural characterization of the first silver copper oxide. Synthesis reaction; Chemical analyses; Thermal stability of the oxide; X-ray photoelectron spectra; Crystal structure determined thru powder x-ray, neutron and electron diffraction; Electronic structure; Magnetic and transport properties; Electrochemical characterization.

Silver sheathed Bi-2223 tapes have been investigated by transport and magnetization measurements in the temperature range between 4.2 K and 77 K for magnetic fields up to 12 T. The superconducting current through the tape can be explained by assuming a network of platelike grains coupled by weak links. At high temperatures the critical current is governed by flux creep of pancake vortices within the grains. At temperatures below 40 K this intragrain critical current exceeds the intergrain Josephson current leading to a weak link limitation in the tape. In this picture the differences between critical transport and magnetization currents can be explained by a reduction of the geometrical length scale of current loops. An improvement of the weak link current density is observed in multifilamentary wires and tapes with AgCu sheath material. [ABSTRACT FROM PUBLISHER]

Joining of NiTi alloy to itself has been realised by vacuum brazing process using AgCu28 eutectic as filler metal. Microstructures, mechanical and shape memory behaviour have been investigated. The shearing strength of the brazed joint exceeds 100 MPa, and rupture occurs at the diffusion layer of parent metal beside brazing metal. The brazed joint will be stronger than parent metal on condition of the specimen with a joint of lap length 10 times of plate thickness. The brazed specimen shows a good shape memory behaviour. From the point of view of practice, the brazing joint design principle and brazing quality improvement have been discussed. [ABSTRACT FROM AUTHOR]

Large metal enhanced luminescence was realized at the vicinity of easily fabricated Ag–Cu alloy nanoparticles upon tuning of their surface plasmon resonance spectra by changing only one experimental variable—the annealing temperature, for maximum spectral overlap with the emission and excitation spectra of the luminophores. We observed strong emission enhancement of luminophores (141.48±19.20 times for Alexa Fluor 488 and 23.91±12.37 times for Alexa Fluor 594) at the vicinity of these Ag–Cu nanoparticles, which is significantly larger than for pure Ag nanoparticles. We present theoretical calculations to provide insights into these experimental findings. [ABSTRACT FROM AUTHOR]

Manschot et al. [Appl. Phys. Lett. 85, 3250 (2004)] predicted that the critical current to switch the magnetizations in a ferromagnetic/nonmagnetic/ferromagnetic nanopillar from parallel to antiparallel could be reduced by up to a factor of 5 by pairing nonmagnetic leads with different effective resistances (resistivity times spin diffusion length). Comparing switching currents for Co/Cu/Co nanopillars with Pt and AgSn(5%) leads on alternate sides of the nanopillar did not give the large reduction predicted by Manschot et al. Possible reasons for this lack are discussed. [ABSTRACT FROM AUTHOR]

Inkjet printing and photonic sintering parameters for silver and copper nanoparticle inks on flexible polyimide and environmentally friendly cardboard substrates have been studied. The results were utilised to manufacture prototype passive ultra-high frequency (UHF) radio-frequency identification (RFID) tag antennas. The manufactured tags showed peak read ranges of 2.9-5.5 m. [ABSTRACT FROM AUTHOR]

Compounds (IVa,b) crystallize isostructurally in the triclinic space group P $\bar 1$ (single crystal XRD). [ABSTRACT FROM AUTHOR]

The article focuses on the work of researchers at Tampere University in Finland for exploring the factors affecting printing of RFID tags on flexible substrate. They aims to create low-cost environmentally friendly devices needed to create the Internet of Things and used photonic sintering of silver and copper nanoparticle inks to produce prototype UHF RFID tag antennas on flexible substrates.