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In this work, the structure of silica thin films synthesized with three different SiO2 precursors and obtained by the sol–gel method and dip coating technique was studied. Additionally, the influence of Ag addition on the obtained silica sols and then gel structure was investigated. Silica coatings show antireflective properties and high thermal resistance, as well as hydrophobic or hydrophilic properties. Three different silica precursors, TEOS (tetraethylorthosilicate), DDS (dimethyldietoxysilane) and AerosilTM, were selected for the synthesis. DDS added to silica sol act as a pore size modifier, while Ag atoms are known for their antibacterial activity. Coatings were deposited on two different substrates: steel and titanium, dried and annealed at 500 °C in air (steel substrate) and in argon (titanium substrate). For all synthesized films, IR (infrared) spectroscopic studies were performed together with GID and XRD (Grazing Incidence Diffraction, X-ray Diffraction) measurements. The topography and morphology of the surface were traced by SEM and AFM microscopic methods, providing information on the samples' roughness, particle sizes and thickness of the particular layers. The wetting angle values were also measured. GID and XRD measurements pointed to the distinct contribution of an amorphous phase in the samples, allowing us to recognize the crystalline phases and calculate the silver crystallite sizes. The FTIR spectra gave information on the first coordination sphere of the studied samples. [ABSTRACT FROM AUTHOR]

The effect of adding a small amount of Ag on the microstructure evolution and superplastic properties of Mg-Y-Er-Zn (WEZ612) alloys was systematically studied. The basal texture of the refined WEZ612 alloy produced by equal channel angular pressing was altered to a non-basal structure upon the addition of Ag. Ag addition also refined the grain size and promoted the formation of a large number of nano-14H-long period stacking ordered phases. Using high-resolution transmission electron microscopy, many nano-precipitated phases were detected on the basal plane of the Mg-Y-Er-Zn-1Ag (WEZ612–1Ag) alloy, The nano-precipitated phases on the basal plane improved the thermal stability of the alloy, lowered the deformation activation energy (Q), and improved the stress sensitivity index (m). At 523 K with a strain rate of 10−2 s−1, the Q value of WEZ612 was higher than that of WEZ612–1Ag (299.14 and 128.5 kJ mol−1, respectively). In contrast, the m value of the WEZ612 alloy (0.16) was lower than that of the WEZ612–1Ag alloy (0.46). At 623 K with a tensile rate of 10−2 s−1, the WEZ612 and WEZ612–1Ag alloys were elongated by 182% and 495%, respectively, with the latter exhibiting high-strain-rate and low-temperature superplasticity. The improved superplasticity of the WEZ612-1Ag alloy is attributed to the nano-precipitated phases, which effectively limit the cavity extension during superplastic deformation.

Seawater, one of nature's most bountiful resources, holds promise as a valuable and inexhaustible raw material for hydrogen production through water electrolysis. However, to combat chloride corrosion and maintain a stable operating state, it is essential to design strong and effective electrocatalysts appropriate for the hydrogen evolution reaction (HER). Herein, we demonstrate that Ni 40 Ti 20 Zr 38 Ag 2 alloy, after the successive arc-melting, melt-spinning, and dealloying treatments, generates a distinctive nanosheet structure. In alkaline seawater electrolyte (1 M KOH + natural seawater), this materials for HER not only could achieve a smaller overpotential of 69 mV driving 10 mA cm−2, but also possess excellent stability including the 10 mA cm−2 current density over 24 h and 3000 cycles measurement. This is mainly attributed to the array of cascading interconnected nanosheets and the incorporation of Ag, as well as the resulting electron transfer and changes in the chemical state of the elements on the catalyst surface. This work proposes a novel design strategy for alloy materials for preparing an efficient HER electrocatalyst in alkaline seawater. The dealloyed NiTiZrAg can be used as an efficient and stable electrocatalyst for hydrogen production in alkaline seawater. [Display omitted] • NiTiZrAg-20 electrocatalysts with nanosheet arrays were constructed by dealloying. • Ag promotes the electron transfer between components and changes in chemical states. • The NiTiZrAg-20 showed superior HER performance in alkaline seawater. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of Sn–Bi solder alloys with various Ag and In addition are comparatively investigated. The results illustrate that the tensile strength and ductility of the solder alloy could be dramatically enhanced with negligible loss of the plasticity. Especially, the Sn–Bi solder alloy with 0.4 wt. % Ag and 1.5 wt. % In exhibits the maximum tensile strength and elongation of 79.7 MPa and 45.9%, respectively. The microstructure of the Sn–Bi solder alloys is mainly composed of Bi-rich and β-Sn phases. With the addition of elements Ag and In, the microstructure is significantly refined, and the lamellar eutectic structure with thinner interlayer spacing could be detected. Element Ag tends to form Ag3Sn phase while element In solutes in the Sn matrix. The mechanical properties of the as-prepared Sn–Bi solder alloy are improved attributed to the precipitated-phase strengthening of the fined Ag3Sn phase and the refinement effect of In on coarse Bi-rich phase.

Equal-channel angular pressing was conducted on 6063 aluminum alloy containing a small silver (Ag) addition up to 4 passes at room temperature following route Bc. Mechanical properties assessed by nanoindentation measurements indicated that the Ag affected the plastic deformation mechanism by suppressing grain boundary sliding. Eventually, this led to the occurrence of dynamic recovery following the second pass. The occurrence of dynamic recovery was confirmed by differential scanning calorimetry. X-ray diffraction analysis revealed a steady-state condition of crystallite size, microstrain and dislocation density after the first pass due to the occurrence of dynamic recovery, indicating that the Ag stabilizes the microstructure. Recrystallization kinetics predicted by the Johnson–Mehl–Avrami model, involved two distinct stages being characterized by different Avrami exponent values. Both stages exhibited relatively high activation energy values, revealing that Ag improves the thermal stability. Analysis of contributions of various strengthening mechanisms showed that significant contribution arises from dislocation density and Ag provides additional strengthening. The relatively low magnitudes of residual stress further revealed the role of Ag as stress reliever. [ABSTRACT FROM AUTHOR]

The effect of adding a small amount of Ag on the microstructure evolution and superplastic properties of Mg-Y-Er-Zn (WEZ612) alloys was systematically studied. The basal texture of the refined WEZ612 alloy produced by equal channel angular pressing was altered to a non-basal structure upon the addition of Ag. Ag addition also refined the grain size and promoted the formation of a large number of nano-14H-long period stacking ordered phases. Using high-resolution transmission electron microscopy, many nano-precipitated phases were detected on the basal plane of the Mg-Y-Er-Zn-1Ag (WEZ612–1Ag) alloy, The nano-precipitated phases on the basal plane improved the thermal stability of the alloy, lowered the deformation activation energy (Q), and improved the stress sensitivity index (m). At 523 K with a strain rate of 10−2 s−1, the Q value of WEZ612 was higher than that of WEZ612–1Ag (299.14 and 128.5 kJ mol−1, respectively). In contrast, the m value of the WEZ612 alloy (0.16) was lower than that of the WEZ612–1Ag alloy (0.46). At 623 K with a tensile rate of 10−2 s−1, the WEZ612 and WEZ612–1Ag alloys were elongated by 182% and 495%, respectively, with the latter exhibiting high-strain-rate and low-temperature superplasticity. The improved superplasticity of the WEZ612-1Ag alloy is attributed to the nano-precipitated phases, which effectively limit the cavity extension during superplastic deformation. [ABSTRACT FROM AUTHOR]

The hardness and wear resistance of cast Mg-6Gd-0.6Zr alloy were increased by the addition of 2 wt.% Ag. The microstructural studies of Mg-6Gd-0.6Zr–2Ag exhibited Ag-containing compounds within the α-Mg matrix. The addition of Ag increased the hardness by 20–30% at various temperatures up to 300 °C. The dry sliding wear behaviors of Mg-6Gd-0.6Zr and Mg-6Gd-0.6Zr–2Ag alloys were investigated under normal loads of 5, 20 and 40 N at wear temperatures of 25–325 °C against 52,100 steel using a pin-on-disk tribometer. Under a normal load of 5 N at various wear temperatures, Mg-6Gd-0.6Zr–2Ag alloy showed a higher wear resistance than Mg-6Gd-0.6Zr. However, under higher normal loads of 20 and 40 N at temperatures of 125–225 °C and 125–175 °C, respectively, the Ag-containing alloy showed a higher wear rate than the base alloy. The results also showed that the wear rates decreased with increasing temperature to critical temperatures of 225 °C for Mg-6Gd-0.6Zr and 275 °C for Mg-6Gd-0.6Zr–2Ag, which were then followed by a rise due to thermal softening and higher plastic deformation of the alloys.

Two Al-Cu-Mg(-Ag) aluminium alloys, having the same base composition of Al-5.11Cu-0.96 Mg-0.58Mn-0.12Zr (wt.%) but different Ag contents, 0 and 0.7 Ag (wt.%), and accordingly denoted 0A and 7A samples, were aged at 185 °C. In early-ageing, the formation of disk-like Mg-Cu and Mg-Ag nano(co–)clusters can be quantitatively examined by Small angle X-ray scattering (SAXS), respectively. In the prolonged ageing of the 0A samples, the thickening in the disk-like θ-precipitates leads to a lower aspect ratio. For S-precipitates, the change in the total surface area and the single-particle surface area indicates that the coalescence mechanism is prevalent from peak-ageing to over-ageing, and then after over-ageing, the precipitate coarsening dominates. The coarsening in S and θ precipitates presumably leads to a lower mechanical strength. Alternatively, in the aged 7A sample, the SAXS technique in conjunction with transmission electron microscopy (TEM) quantitatively reveals Ω-precipitates possessing a nearly constant thickness but an increase in diameter with ageing time. Additionally, the stable behaviors of the total surface and size of S-precipitates illuminate that the coalescence/coarsening mechanisms are significantly slowed down. The concurrently-existing precipitation kinetics of Ω and S have provided an in-depth understanding of the higher strength of the aged 7A sample.

[Display omitted] • Biofriendly and anti-corrosive Zr-Ti-Ag thin film metallic glasses were developed. • Ag didn't directly form the passive film but altered the passive film performance. • The formation and breakdown processes of passive films were profiled. Low-cost and non-cytotoxic ternary Zr-Ti-Ag thin film metallic glasses (TFMGs) were synthesized by DC magnetron sputtering. Results revealed that Ag addition enhanced the crystallization resistance and thermal stability of TFMGs. An appropriate Ag addition favored the mechanical property and corrosion resistance of TFMGs, while the excessive Ag addition had the opposite effect. Moreover, Ag did not directly form the passive film but altered the passive film stability and anti-corrosion capacity of TFMGs by inducing the disordered atomic arrangement, forming a dense microstructure, and tuning the corrosion-resistant Zr and Ti components. With low Young's modulus of 116.2 GPa and passive current density of 0.45 × 10−7 A/cm2, the TFMG with an Ag target sputtering power of 11 W exhibited superior corrosion resistance, suggesting its application potential as biomaterials. [ABSTRACT FROM AUTHOR]

The effect of 0.5, 1 and 1.5 wt% Ag addition on the microstructural evolution, thermal stability and mechanical properties of an Mg–5 wt% Gd–1 wt% Y (GW51) alloy was investigated. The as-cast microstructure of the base alloy consisted of the Mg5(Gd,Y) phase in the α-Mg matrix. The obtained results revealed that Ag addition refines the dendritic microstructure of the base alloy, promotes the formation of the new Mg16Gd2YAg phase, and increases the volume fraction of the Mg5(Gd,Y) particles. These events resulted in improved hardness, strength, and microstructural stability of the Ag-containing alloys in the as-cast condition and after prolonged exposure to high temperature. The superior mechanical properties of the quaternary alloys over those of the tertiary alloy at low and high temperatures stems from the solid solution hardening effect of Ag, presence of the thermally stable Mg16Gd2YAg particles, and higher volume fraction of the Mg5(Gd,Y) particles. These particles can slow down the grain growth during exposure to high temperature, enhancing the stability and strength of the alloys at both room and high temperatures.

The influence of Ag on the microstructure evolution of an aged Al–Cu–Li–Mg alloy was studied. The coarse Cu-rich precipitates containing Ag and Mg were found during the whole ageing process of Al–Cu–Li–Mg–Ag alloy. Besides, Ag addition in the Al–Cu–Li–Mg alloy accelerates the hardness value reduction of the overaged alloy. When the alloy was over heat-treated, more coarse Cu-rich phases containing Ag and Mg are presented at the grain boundaries. These discrete coarse precipitates accelerate the hardness reduction of the overaged alloy.

In this study, the influence of minor Ag addition on the microstructure, mechanical and corrosion properties of an Al-Zn-Mg-Cu-Zr (7449) alloy with Zn/Mg ratio of 4 was systematically investigated using various materials characterization techniques, Slow Strain Rate Test (SSRT), Potentiodynamic Polarization (PDP) and Intergranular Corrosion (IGC) measurements. Microstructure characterization by Scanning Electron Microscopy (SEM) and Differential Scanning Calorimetry (DSC) showed that Ag partitioning in the eutectic Mg(Zn,Cu,Al) 2 phase occurs resulting in an increase in its solvus line. After processing to the T4 condition, Ag was partially in solid solution with the excess forming an Ag-rich AlAgZnMgCu phase. Scanning-Transmission Electron Microscopy (STEM) showed evidence of quench-induced η -Mg(Zn,Cu,Al) 2 precipitates at the grain boundaries (GBs) in the T4 condition with ∼3 at.% Ag in the Ag-modified alloy. STEM and Atom Probe Tomography (APT) confirmed that ∼1 at. % Ag was present in both the matrix and GB precipitates in the Ag-modified alloy after T76 aging. Furthermore, the frequently reported decrease in the PFZ width with Ag addition was not observed after T76 aging, with both alloys having a similar PFZ width. Despite higher hardness/strength in the T4 condition with Ag addition, no enhanced age hardening response and alteration of the precipitation kinetics was observed during artificial aging at 121 °C. In fact, Ag addition in a 7xxx alloy with Zn/Mg ratio of 4 was found to be detrimental to mechanical properties, stress corrosion cracking, pitting and IGC resistance after T76 aging, which is attributed to the presence of the Ag-rich AlAgZnMgCu phase. [Display omitted] • Ag addition in 7449 leads to Ag partitioning in eutectic Mg(Zn,Cu,Al) 2 phase and an increase in its solvus temperature. • Ag is partly in solid solution after solution heat treatment. • Ag-rich AlAgZnMgCu phase forms with Ag addition in a 7xxx alloy with Zn/Mg ratio of 4. • Ag addition in a 7xxx alloy with Zn/Mg ratio of 4 did not improve alloy properties. [ABSTRACT FROM AUTHOR]

The effects of Ag (0, 0.5, 1, and 2 wt%) content on the microstructure and mechanical properties of SLMed AZ61 Mg–Al–Zn alloy in the as-deposited and heat-treated conditions were investigated. The microstructure of SLMed AZ61 Mg–Al–Zn alloy is composed of α-Mg matrix and eutectic of α-Mg and Mg17Al12 phase at grain boundaries. The addition of Ag inhibited the growth of β-Mg17Al12 phase and further refined the grain size. After adding 2 wt% Ag, the volume fraction of β-Mg17Al12 phase is decreased from 40.53 to 30.27%, and the average grain diameter is decreased from 2.35 to 1.82 μm. Mg54Ag17 phase particles were formed after Ag was added and distributed in the grain boundary, which was beneficial to enhance the mechanical properties of Mg–Al alloy. After 8-h solution treatment at 420 °C β-Mg17Al12 phase was basically dissolved in α-Mg matrix, which was beneficial to the precipitation of discontinuous β phase during aging treatment, and this discontinuous β phase could effectively enhance the strength of Mg–Al alloy. When the content of Ag is 2 wt%, the mechanical properties and corrosion resistance of Mg–Al alloy are enhanced. After solution treatment, the mechanical properties of Mg–Al alloy are decreased, but the corrosion resistance is greatly enhanced. After aging treatment, the mechanical properties are increased, but the corrosion resistance is decreased. [ABSTRACT FROM AUTHOR]

The effect of 0.5, 1 and 1.5 wt% Ag addition on the microstructural evolution, thermal stability and mechanical properties of an Mg–5 wt% Gd–1 wt% Y (GW51) alloy was investigated. The as-cast microstructure of the base alloy consisted of the Mg 5 (Gd,Y) phase in the α -Mg matrix. The obtained results revealed that Ag addition refines the dendritic microstructure of the base alloy, promotes the formation of the new Mg 16 Gd 2 YAg phase, and increases the volume fraction of the Mg 5 (Gd,Y) particles. These events resulted in improved hardness, strength, and microstructural stability of the Ag-containing alloys in the as-cast condition and after prolonged exposure to high temperature. The superior mechanical properties of the quaternary alloys over those of the tertiary alloy at low and high temperatures stems from the solid solution hardening effect of Ag, presence of the thermally stable Mg 16 Gd 2 YAg particles, and higher volume fraction of the Mg 5 (Gd,Y) particles. These particles can slow down the grain growth during exposure to high temperature, enhancing the stability and strength of the alloys at both room and high temperatures. [ABSTRACT FROM AUTHOR]

Polycrystalline La 0.85 Sr 0.15 MnO 3 :Ag x (LSMO:Ag x , 0 ≤ x ≤ 0.5) ceramics were synthesized using sol-gel procedure. All specimens showed rhombohedral perovskite structures in R 3 ‾ c space group. As the amount of Ag increased, grain size of ceramics increased, and resistivity accordingly decreased. Large temperature coefficient of resistivity (TCR) of 22.9% K−1 was obtained at room temperature (289.2 K) for x = 0.4. Interestingly, analyses of resistivity-temperature (ρ - T) experimental data showed that conduction mechanism over entire temperature region perfectly matched theoretical percolation model. This reveals that electrical transport properties of LSMO:Ag x ceramics are mainly affected by domains, grain boundaries (GBs), and Kondo-like spin-dependent scattering. It also demonstrates the coexistence of paramagnetic (FM) and ferromagnetic (PM) phases in LSMO:Ag x ceramics. The ρ-T and scanning electron microscopy (SEM) results confirmed that the introduction of Ag weakened these scattering effects. [ABSTRACT FROM AUTHOR]

In this work, the effects of Ag addition on phase transitions, microstructure and solder/copper interfaces of Sn99.1−xCu0.9Agx alloys were studied using differential scanning calorimetry, X-ray diffractometry, electron scanning microscopy and energy-dispersive X-ray spectroscopy. The results showed that the addition of Ag to the Sn99.1Cu0.9 alloy changes the thermal behavior of the melting and solidification points of studied alloys. The presence of silver also induced the formation of the Ag3Sn phase and decreased the amount of the Cu6Sn5 compound. [ABSTRACT FROM AUTHOR]

The growth of interfacial IMC in Cu/Sn/Cu and Cu/Sn-5.0Ag/Cu micro solder joints and the trace of Ag atoms migration in Cu/Sn-5.0Ag/Cu micro solder joint during reflow with and without temperature gradient (TG) were investigated. The growth of interfacial IMC during isothermal reflow was symmetrical and controlled by grain boundary diffusion; whereas that during reflow under TG was asymmetrical and controlled by reaction rate. In addition, the Cu and Ag atoms could migrate from the hot end to the cold end driven by TG and react with Sn atoms to form Cu 6 Sn 5 and plate-type Ag 3 Sn at the cold end in the Cu/Sn-5.0Ag/Cu solder joint. As the reflow time prolonged, the plate-type Ag 3 Sn would embed in the Cu 6 Sn 5 phase. Due to the larger interfacial energy of Cu 6 Sn 5 /Ag 3 Sn and the smaller absolute value of the enthalpy of formation for Ag 3 Sn, the Ag 3 Sn would dissolve and release Sn atoms to support Cu 6 Sn 5 growth by consuming the surplus Cu atoms generated by the additional TG, leaving Ag atoms in the full IMC joint. Specifically, the Ag element remained in the Cu 6 Sn 5 phase with Ag content of 0.55 wt%. [Display omitted] • Ag atoms migrated to the cold end and precipitated as plate Ag 3 Sn under TG. • The larger γ 2 and the smaller absolute value of the enthalpy of formation for Ag 3 Sn lead to the dissolution of Ag 3 Sn. • Ag 3 Sn would dissolve to release Sn atoms, supporting Cu 6 Sn 5 growth by consuming the surplus Cu atoms. • The Ag element content was as high as 0.55 wt% in the Cu 6 Sn 5 phase. [ABSTRACT FROM AUTHOR]

We study the effects of Ag addition on thermal stability and thermophysical properties of Ti-Zr-Ni icosahedral quasicrystals. The Ag addition results in increasing the coherence length and thermal stability of the icosahedral phase (i-phase) of the as-cast Ti35.2Zr43.8Ni21 alloy, which are maximized at around 4 at.% Ag addition. Differential scanning calorimetry (DSC) and electrostatic levitation (ESL) experiments reveal that the addition suppresses the i-phase decomposition on heating and cooling. We find that considerable amount of the i-phase remains in the samples processed by radiational cooling in ESL as the Ag concentration increases. These results demonstrate that Ag addition stabilizes the i-phase of the Ti35.2Zr43.8Ni21 alloy. No anomalous effect of Ag addition is found on density and viscosity of the Ti35.2Zr43.8Ni21 liquid.

Abstract Effects of Ag on age hardening response and intergranular corrosion resistance of Al-Mg alloys have been examined in this research. In the aging process, Ag addition can promote the formation of numerous fine-scale rod-like T-Mg 32 (Al, Ag) 49 phases and granulate-shaped β″-(Al, Ag) 3 Mg phases which distributed in the matrix uniformly. These dispersed particles enhanced the age hardening response conspicuously. Additionally, Ag can also inhibit the formation of the β phase (Al 3 Mg 2) along the grain boundary and raised the corrosion potential E corr of Al-Mg alloys. As a result, the intergranular corrosion resistance of Al-Mg alloys was improved by the addition of Ag. Highlights • The distribution, size and type of precipitates changed by Ag addition in Al-Mg alloys. • The phase structures of the precipitates in Al-Mg-Ag alloys were discussed in detail by TEM and HAADF-STEM. • The mechanical properties and corrosion resistance of Al-Mg alloys were both improved by alloying Ag. [ABSTRACT FROM AUTHOR]

Ag-doped GdBa2Cu3O7−δ (GdBCO)-coated conductors are fabricated via a metal-organic process. The X-ray diffraction and scanning electron microscopy results show that the growth conditions of the GdBa2Cu3O7−δ matrix are modified, resulting in less a-axis growth and much smoother surface morphology and finally giving rise to much improvement of superconducting performance in a wide range of processing parameters. The orientation behavior and mechanism of Ag-doped GdBCO films are investigated. To reasonably explain the orientation behavior of Ag-doped GdBCO films, a simple nucleation model for Ag-doped GdBCO is established, suggesting quasi-liquid phases are perfected by Ag. As a consequence, a-axis nucleation is suppressed and strong c-axis nucleation is achieved in a wider processing window. [ABSTRACT FROM AUTHOR]

Aging-hardening response of Mg-7Al-2Sn (wt%) alloy can be remarkably accelerated by a small addition of silver (Ag). Using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) coupled with high resolution energy dispersive X-ray spectroscopy (EDS) mapping, for the first time, segregation of solute atoms (Ag in this case) was observed at the interphase boundary between continuous Mg 17 Al 12 precipitate and magnesium matrix in Mg-7Al-2Sn alloy with 0.7 wt% Ag addition. Substantial size refinement and increased number density of Mg 17 Al 12 precipitates may be responsible for the enhanced aging-hardening response in Mg-7Al-2Sn alloy with Ag addition. [ABSTRACT FROM AUTHOR]

The effect of Ag and Cu addition on clustering behavior of Al-Mg-Si alloys during natural aging (NA) and artificial aging (AA) was investigated by hardness measurement, tensile test and atom probe tomography analysis. The results show that both Ag and Cu atoms could enter clusters and GP-zones, change the Mg/Si ratio and increase their volume fractions. Compared with the A1 base alloy, the clusters in the Ag/Cu-added alloys more easily transform to β″ phases for size and compositional similarity, and the strengthening ability of these particles is enhanced by the increased volume fraction and shear modulus. In NA condition, Cu is greater in improving the volume fraction of clusters than Ag and thus produces higher T4 temper hardness. In AA condition, in contrary, Ag is more effective in facilitating the formation and growth of particles than Cu due to the stronger Ag-Mg interaction and the high diffusivity of Ag atoms in Al matrix, leading to highest hardening response. Compared to the Cu-added alloy, the Ag-added alloy shows higher precipitation kinetics during AA treatment and maintains a lower T4 temper hardness. [ABSTRACT FROM AUTHOR]

The combined effect of pre-aging and Ag/Cu addition on natural aging and bake hardening in Al-Mg-Si alloys were studied by Vickers microhardness measurement, tensile test, atom probe tomography and transmission electron microscopy. The results showed that Ag and/or Cu addition could further enhance the positive effect of pre-aging on bake hardening for Al-Mg-Si alloys. Although the pre-aged alloys with individual Ag/Cu addition had higher paint bake hardness, the hardness in T4P temper was relatively high due to effectively forming of Cluster(2) during pre-aging. While the pre-aged Ag-Cu-added alloy had low T4P temper hardness and higher bake hardening response. The strong interaction energies between Ag/Cu atoms and Mg atoms were responsible for the facilitated clustering and precipitation processes. After paint bake treatment, most of Ag atoms accumulated preferentially at β″/α-Al matrix interface, while Cu atoms entered into the interior of β″resulting in disordered structure within the precipitate. [ABSTRACT FROM AUTHOR]

The microstructure of Sn-11Sb-6Cu Babbitt consists of a soft solution matrix and hard particles (SnSb and Cu 6 Sn 5 ). The soft solution matrix acts as solid lubrication and embedability provider, and the hard particles provide the sufficient load carrying capacity. In the present study, the effects of Ag micro-addition on the structure and mechanical properties of Sn-11Sb-6Cu Babbitt were investigated by optical microscopy, vickers microhardness tester, X-ray diffractometer, scanning electron microscope and servo-hydraulic materials testing system. The results indicate that a new intermetallic compound Ag 3 Sn is formed after Ag is added to Sn-11Sb-6Cu, which increases the microhardness and improves the strength and ductility of Sn-11Sb-6Cu Babbitt. It is also found that the addition of 1.0 wt% Ag to Sn-11Sb-6Cu Babbitt has the potential to improve the load carrying capacity without sacrificing the embedability. [ABSTRACT FROM AUTHOR]

In this study, the influences of Ag addition to Sn-58Bi solder on SnBi/Cu interfacial reaction and fracture behavior of the aged SnBiAg/Cu solder joints were investigated. The results reveal that the Ag element in the solder can diffuse into the Cu substrate during the soldering and aging process, forming a Cu-Ag alloy layer around the joint interface. The Bi segregation was not observed at the aged SnBiAg/Cu interface, and the embrittlement will not occur at the aged SnBiAg/Cu solder joints once the Bi segregation was restrained. [ABSTRACT FROM AUTHOR]

La0.67Sr0.33MnO3:mol-%Agx(LSMO:Agx,x = 0, 0.1, 0.2, 0.3 and 0.4) polycrystalline ceramics were prepared by chemical co-precipitation methods. All of the LSMO:Agxsamples showed rhombohedral perovskite structure with a space group of. The diffraction peaks of metallic Ag did not appear in the XRD graph, due to the Ag substitution at A sites (La3+or Sr2+ions) and the evaporation loss of the element Ag in the process of high-temperature sintering, or the residual amount of Ag beyond the sensitivity of the XRD. With the increase of Ag addition, unit cell volume (V), metal−insulator transition temperature (Tp) and conductivity atTp(ρTp) of the LSMO:Agxsamples increased significantly. At the same time, the temperature coefficient of resistance (TCR%), temperature peak of theTCR% (Tk) and the figure of merit (Z) reached the optimal values of 3.3% K−1, 367 K and 0.049 atx = 0.3. Ag substitution at A sites (La3+or Sr2+ions) and gathering at grain boundaries (GBs) were proposed to explain the existence of Ag addition. All results suggested that the enhancement of electrical properties was due to silver-doping and it increased the bond angles of Mn−O−Mn (θMn−O−Mn)and the bond distance of Mn−O (dMn−O), improving Mn4+concentration, grain sizes and GBs connectivity in LSMO:Agxceramics. [ABSTRACT FROM AUTHOR]

Abstract The article reports on structure, mechanical, optical, photocatalytic and biocidal properties of Ti–Ag–O films. The Ti–Ag–O films were reactively sputter-deposited from a composed Ti/Ag target at different partial pressures of oxygen on unheated glass substrate held on floating potentialU fl. It was found that addition of ~2 at.% of Ag into TiO2film has no negative influence on UV-induced hydrophilicity of TiO2film. Thick (~1,500 nm) TiO2/Ag films containing (200) anatase phase exhibit the best hydrophilicity with water droplet contact angle (WDCA) lower than 10° after UV irradiation for 20 min. Thick (~1,500 nm) TiO2/Ag films exhibited a better UV-induced hydrophilicity compared to that of thinner (~700 nm) TiO2/Ag films. Further it was found that hydrophilic TiO2/Ag films exhibit a strong biocidal effect under both the visible light and the UV irradiation with 100% killing efficiency ofEscherichia coliATCC 10536 after UV irradiation for 20 min. Reported results show that single layer of TiO2with Ag distributed in its whole volume exhibits, after UV irradiation, simultaneously two functions: (1) excellent hydrophilicity with WDCA < 10° and (2) strong power to killE. colieven under visible light due to direct toxicity of Ag.

The effects of Ag and/or Cu additions on the natural aging and precipitation hardening behavior of Al-Mg-Si alloys were investigated by using hardness test, differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). Both Ag and Cu additions enhanced the hardening kinetics of Al-Mg-Si alloys during natural aging (NA) and artificial aging (AA) treatments. The strong interaction of Cu, Ag and Mg atoms is responsible for the improved precipitation kinetics of these alloys, resulting in a refinement of clusters and precipitates. The stronger interaction between Ag and Mg results in lower T4 hardness and higher AA hardness, compared to Cu. This is potentially beneficial for automobile applications where rapid hardening during paint baking is required. Both Ag and Cu additions reduce the detrimental effect of NA on subsequent AA, due to the formation of Ag or Cu-containing clusters. The clear advantage of Ag addition, compared to Cu, is the improvement of precipitation hardening response of Al-Mg-Si alloys. [ABSTRACT FROM AUTHOR]

In this study, the effects of Ag variations on dynamic recrystallization (DRX), texture, and mechanical properties of ultrafine-grained Mg–3Al–1Zn alloys are investigated. The results suggest that Ag segregation and Al–Zn–Ag clusters form in the Mg matrix with Ag addition less than 1 wt%, which retard DRX and the growth of the DRXed grains. The resulting grain size decreases from 513 to 316 nm. As the Ag addition increases to 2 wt%, the Mg54Ag17 phase precipitates along the grain boundary, which plays an important role in restricting DRXed grain growth via grain boundary pinning effect. The resulting grain size is 375 nm with a bimodal grain size distribution. The extrusion texture of the investigated alloys is in fairly scattered orientation distribution. The weak basal texture and ultrafine grain size lead to the high yield asymmetry ratio. The Ag-containing extruded alloys exhibit an increase in the tensile and compressive properties. The strengthening mechanisms due to grain refinement, dislocations, solid solution, precipitates, solute clusters, and segregation are discussed. [ABSTRACT FROM PUBLISHER]

We report the impact of silver addition on granularity of NdFeAsO 0.8 F 0.2 superconductor. The ac susceptibility and electrical resistivity under magnetic field are measured to study the improvement in weak links of NdFeAsO 0.8 F 0.2 with addition of Ag x ( x = 0.0–0.3). The Ag free NdFeAsO 0.8 F 0.2 compound shows superconductivity at around 51.8 K. Typical two step superconducting transitions due to the inter- and intra-grain contributions, induced from the combined effect of superconducting grains and the inter-granular weak-coupled medium respectively are clearly seen in susceptibility [ χ ( T )] plots. In comparison to the pure NdFeAsO 0.8 F 0.2 compound, the coupling between the superconducting grains is significantly improved for 20 at% silver doped sample, and the same is deteriorated for higher Ag content i.e., for 30 at%Ag sample. The magneto transport measurements ρ ( T ) H of polycrystalline 20 at% Ag doped NdFeAsO 0.8 F 0.2 exhibited the upper critical filed [ H c2 (0)] of up to 334 T, which is slightly higher than the one observed for pure NdFeAsO 0.8 F 0.2 . The flux flow activation energy ( U 0 / k B ) varies from 7143.38 K to 454.77 K with magnetic field ranging from 0 T to 14 T for 20 at% Ag doped NdFeAsO 0.8 F 0.2 . In this investigation, our results show that limited addition of Ag improves the granular coupling of superconducting grains of NdFeAsO 0.8 F 0.2 compound. [ABSTRACT FROM AUTHOR]

Pristine and Ag nanoparticle modified TiO 2 nanofibers were fabricated by an electrospinning technique using polyvinyl pyrrolidone (PVP) and tetrabutyl titanate as precursor. The morphology and structure of the as-synthesized nanofibers were characterized by scanning electron microscopy and X-ray diffraction. It was found that the presence of Ag had a significant effect on the morphology and crystal structure of TiO 2 nanofibers, and that Ag addition could promote the phase transformation from anatase to rutile. H 2 S sensing properties of the sensors based on TiO 2 nanofibers were also investigated. The results showed that Ag/TiO 2 nanofibers exhibited better gas sensing performances than pristine TiO 2 nanofibers and the possible sensing mechanism was discussed. [ABSTRACT FROM AUTHOR]

Y 1– x Gd x Ba 2 Cu 3 O 7–δ -Ag ( x = 0, 0.25, 0.5, 0.75, 1) thin films were prepared on oxide buffered Hastelloy substrates by low fluorine metalorganic depostion (MOD) process. The effects of co-doping of Ag and Gd on the microstructures and superconducting properties of YBCO thin films are investigated with respect to improvement on texture and superconducting performance in case of optimized doping content. It is found that optimum addition of Ag and Gd may lead to better c -axis orientation, superior surface microstructure and finally give rise to much improvement of superconducting performance. [ABSTRACT FROM AUTHOR]

La $$_{0.7}$$ (Ca $$_{0.2}$$ Sr $$_{0.1}$$ )MnO $$_{3}$$ :Ag $$_{x }$$ (LCSMO:Ag $$_{x}$$ , x = 0, 0.1, 0.2 and 0.3, mol%) polycrystalline composites were prepared by a solid-state reaction method. With the increasing of Ag addition, the temperature coefficient of resistance (TCR) and the metal-to-insulator transition temperature ( $$T_\mathrm{p}$$ ) reach the maximum values of 9.1 % K $$^{-1}$$ and 258 K for LCSMO:Ag $$_{x}$$ ( x = 0.3) sample, which can be used as a candidate of bolometer or infrared detectors. The improvement of Mn $$^{4+}$$ concentration and grain connectivity by Ag addition is responsible for the enhancement of $$T_\mathrm{p}$$ and TCR values. The fitting curves of electrical resistivity show that the low temperature region ( $$T < T_\mathrm{p}$$ ) is fitted with grain/domain boundary, electron-electron, and magnon scattering mechanisms, as well as the high temperature region ( $$T > T_\mathrm{p}$$ ) is fitted with adiabatic small-polaron hopping mechanism. [ABSTRACT FROM AUTHOR]

Polycrystalline Bi2O2Se/Ag nanocomposites were synthesized by spark plasma sintering process. Their thermoelectric properties were evaluated from 300 to 673 K. With the addition of silver, the conductive second phase Ag2Se and Ag can be observed, which results in a significant enhancement of electrical conductivity. The maximum conductivity is 691.8 S cm-1 for Bi2O2Se/20 vol.% Ag, which increased nearly 500 higher times than the pure Bi2O2Se bulk. ZT value can be enhanced greatly, ~0.07, for Bi2O2Se/5 vol.% Ag at 673 K, which is two times larger than the pure sample. [ABSTRACT FROM AUTHOR]

In this study, we examined the influence of Ag addition on the superconducting properties of polycrystalline FeSe. The samples were obtained by a solid-state reaction and melting. The X-ray diffractometry (XRD) analysis showed the presence of a tetragonal phase, while the energy-dispersive X-ray analysis (EDX) analysis established an inhomogeneous Ag distribution in the grains. The superconducting properties were investigated by measuring the AC magnetic susceptibility's fundamental and third harmonic. The intergranular critical current determined from the AC magnetic susceptibility in the Ag-doped sample was several times higher than that in the undoped one, obtained by melting at approximately the same temperatures. The irreversibility lines were obtained from the temperature dependence of the AC magnetic susceptibility's third harmonic at different DC magnetic fields. It was found that adding Ag increases the irreversibility field in comparison with both undoped (melted and powder-sintered) samples. All results showed that the Ag addition to FeSe samples improves the following intergranular and intragranular properties: screening ability, pinning, activation energy, and critical current and increases the irreversibility field. [ABSTRACT FROM AUTHOR]

We investigated the effects of Ag added SrLaTiO ceramics prepared via a hydrothermal method and sintering. The results indicate that Ag addition is an efficient way to enhance its thermoelectric properties. The maximum thermoelectric figure-of-merit, ZT, is 0.20 at 955 K for x=0.15 sample. [ABSTRACT FROM AUTHOR]

The WS2–Ag composite films were prepared by radio frequency co-sputtering method. The effects of alloying Ag content on composition, microstructure, mechanical properties and friction behaviors have been analyzed by X-ray photoelectron spectroscopy (XPS), grazing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS) and high resolution transmission electron microscope (HRTEM), scratch tester, nano-indentation tester and ball-on-disk tribo-tester. The Ag addition was in present of nanocrystalline phase in the boundary of the crystalline WS2 matrix and induced morphology change, but could not completely prevent the columnar platelets. The columnar platelet was composed of a great deal of nanocrystalline and a small amount of amorphous WS2 phase. There were no substantial variations in the hardness of the composite films when the Ag content was in the range of 0–20.3at.%. The suitable amount of Ag content was benefited for improving the film adhesive strength and wear resistance both in vacuum and humid air environment. Particularly, the composite film with 9.0at.% Ag exhibited the longest wear life (about 7.6×105 cycles in vacuum, 6.7×105 cycles in humid air) under high Hertzian contact pressure (as high as 1.0GPa). The wear mechanism was discussed in terms of the rearrangement of wear track and formation of transfer film. [ABSTRACT FROM AUTHOR]

Highlights: [•] LCMO:Ag x polycrystalline composites with x =0, 0.2 and 0.4 were prepared successfully by chemical coprecipitation. [•] The temperature coefficient of resistance (TCR) near metal–insulator (MI) transition is increased significantly with the addition of Ag. Sharp TCR is seen near T MI with the highest value of up to 28%/K at 271.3K for Ag (x =0.4) sample. [•] The increased magneto-resistance (MR) of 79% is seen at 276K for higher silver added samples in an applied field of 5T. [•] A microstructural model was proposed to describe the role of Ag addition in LCMO:Ag x composites. [•] Improved Mn4+ concentration and grain boundaries (GBs) connectivity caused by Ag addition are responsible for the increased TCR and MR of LCMO:Ag x composites. [Copyright &y& Elsevier]

Ruddlesden-Popper (RP) phase (SrLa)TiO/ xAg ( x=0, 0.05, 0.10, 0.15) are systematically investigated with regard to their phase composition and thermoelectric transport properties. The XRD results show that all oxide samples are of two phases and they have layered microstructure. The electrical conductivity is found to be increased simultaneously. And the absolute Seebeck coefficient decreases firstly and then increases Ag addition, which leads to (SrLa)TiO/ xAg ( x=0.10) sample possesses optimum power factor. The total thermal conductivity lowers with Ag addition. The dimensionless figure of merit, ZT, reaches 0.12 for x=0.10. These results suggest that a proper of metal element Ag addition would be an effective way improving thermoelectric performance of (SrLa)TiO system. [ABSTRACT FROM AUTHOR]

Highlights: [•] We fabricated Sr122+Ag tapes by intermediate sintering process of precursors. [•] Well textured tapes are achieved by a simple rolling process. [•] The resulting samples possess dense and homogeneous microstructure. [•] Transport Jc are the highest values for the iron- pnitides with Ag addition. [Copyright &y& Elsevier]