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A new broadband UV light-based processing method for a screen printable silver oxalate molecular ink is developed that enables structural electronics to be produced on complex thermoformed 3D objects. The production of these 3D devices is driven by the light-induced reduction of silver oxalate to form an interfacial silver nanoparticle layer that allows the ink to transition to a viscous liquid intermediate and elongate up to 50% without cracking during thermoforming. Ultimately, this enables the development of 3D electronics devices with significantly less limitations on geometry, shape, size, and depth in comparison to commercially available inks. UV processing is also effective for 2D traces on low temperature PET substrate, where in situ produced silver nanoparticles can subsequently absorb light and further facilitate the rapid conversion of the silver oxalate to metallic silver through a self-limiting thermal decomposition. The resulting traces have superior electrical properties and are produced in significantly less time in comparison to thermal sintering. Together, UV processing and the silver oxalate molecular ink serve as a platform for both the rapid production of conductive silver traces on low temperature substrates and the development of novel thermoformed 3D human-machine interface devices, areas of interest for both academia and industry.

Silver particle-free inks are under rapid development due to their unique properties. Currently, most of the developed silver particle-free inks contain multiple components. In addition to the necessary solvents and silver precursors, these inks also contain complexing agents, reducing agents, and various additives. While such complex compositions assure good stability and printability of the inks, they hamper the sintering process as excess time and energy are often required to remove residues from various compositions to ensure high conductivities of the printed structures. Thus, a simple ink system is expected. On the other hand, plasma sintering shows its sintering potential in treating silver particle-free inks, but is only employed for the sintering of silver nitrate or silver acetate-based inks. Consequently, developing new particle-free ink systems with simple compositions and exploring the potential of plasma sintering is very meaningful. In this work, a clear and transparent silver particle-free ink was formulated, which can be treated both by low-pressure argon plasma sintering and low-temperature thermal sintering (120–160 °C). The roles of 2-amino-2-methyl-1-propanol (AMP) in the ink formulation were investigated in detail, which not only acts as the solvent but also as the complexing agent for silver oxalate to lower the sintering temperature of the ink. The electrical performance of the formulated ink was examined for both sintering processes for different conditions. The thermal sintering resulted in a resistivity value of 24.3 μΩ·cm on glass substrates after treatment at 160 °C for 60 min, while the plasma sintering yielded a resistivity value of 29 μΩ·cm at 500 W for 30 min. Compared to thermal sintering, plasma sintering achieved a similar electrical performance, but with a more nonuniform film structure. The power, sintering time, and the pressure of argon are key factors responsible for the conductivity of the produced films. Nevertheless, both resistivity values do meet the minimal electrical requirements of most electronic applications. Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347 Projekt DEAL

We herein report the synthesis of nanostructured cyclopalladated complex and its nanosilver composite for the first time. The reaction between Schiff base ligand 4-methyl-N-(3,4-dimethoxybenzylidene)] benzenamine (L) and palladium acetate gave the cyclopalladted complex (Pd1) in nanoscale. Thermal treatment of silver oxalate with Pd1 resulted in the formation of novel nanostructured composite, silver nanoparticle-decorated palladacycle (Pd2). The synthesized compounds were characterized using spectroscopic analysis (FT-IR and 1H NMR), thermal analysis (TGA), XRD and morphological analysis (SEM and TEM). The spectral analysis revealed that complex Pd1 has dimeric structure bridged with acetate ligands between two monomers. SEM images exhibited that Ag-NPs loaded on complex surface in decorated form. TEM photographs showed the particle sizes of composite ≈ 29 nm. Quantum chemical analysis of ligand and complex Pd1 has been carried out by DFT/B3LYP method. There are two suggested isomers for cyclopalladated complex named Pd1 and Pd1* which are theoretically studied and correlated with practical results. HOMO, LUMO energy values, chemical hardness–softness, electronegativity and electrophilic index were calculated. The theoretical data obtained have been confirmed that the Pd1 isomer is more stable than Pd1* isomer which correlated well with practical results. The ligand and complexes screened for antimicrobial activity against five medically important microorganisms, namely Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. The results showed that complex Pd2 displayed the highest activity against the tested microorganisms.

Here, we report for the first time the synthesis of new composite Ag-NPs-loaded core/shell mixed oxides NPs, CdO/Co3O4. First, nano-precursors (1) and (2) consist of mixed (cadmium oxalate/cobalt oxalate) and (silver oxalate/cadmium oxalate/cobalt oxalate), respectively, have been synthesized and characterized. Then, thermal treatment of 1 and 2 at 400 °C resulted in the formation of composites CdO/Co3O4 (3) and Ag-NPs@CdO/Co3O4 (4), respectively. The materials have been characterized by IR, SEM, TEM, TGA and XRD. The morphologies of the materials were described from SEM images. TEM images revealing the formation of core–shell structure with average particles size 5–20 nm. The crystal sizes were calculated from XRD patterns and resulted in 14.21, 14.65, 15.06 and 15.79 nm for 1, 2, 3 and 4, respectively. All the materials undergo tests as antibacterial agents against Gram-positive bacteria (Bacillus subtilis and Enterococcus spp.) and Gram-negative bacteria (E. coli and Pseudomonas aeruginosa). Precursor 2 and composite 4 impart higher inhibition against all the bacterial strains compared to precursor 1 and composite 3.

The size-tunable synthesis of metal nanoparticles (MNPs) is important for revealing their size-dependent unique properties and practical applications. Here, we developed a size-tunable synthesis me...

9 pags., 3 figs., 3 tabs., The presence of extremely large negative linear compressibilities (NLC) in crystalline silver oxalate was discovered in a recent work by using first principles solid-state calculations. Although the minimum value of the NLC was found for a negative applied hydrostatic pressure, in this work the presence of NLC in this material for positive applied pressures is verified experimentally by means of high-pressure X-ray diffraction experiments performed at room temperature in the Beijing synchrotron radiation facility. The results of this study demonstrate with certainty that the compressibility of silver oxalate along [010] crystallographic direction is negative for applied pressures in the range from 0.0 to 0.85 GPa. Since the measured compressibility decreases largely as the pressure decreases, large negative values of the compressibility are expected for negative applied pressures in agreement with the results found using first principles methods. Furthermore, the analysis of the variation of the lattice parameters of the crystal structure of silver oxalate under pressure in the principal axes reference system revealed that this material also exhibits the largest negative area compressibility phenomenon found so far at zero pressure, the values of the compressibilities along two of the principal axes being − 16.7 and − 20.0 TPa−1. The negative compressibility phenomenon in silver oxalate can be rationalized in terms of a “chains of rotating parallelograms” structural model., This work was supported by the National Scientific Foundations of China (Grants 51702330, 51872297 and 11974360).

To satisfy the performance gains of the third-generation semiconductors represented by SiC and GaN during use, novel high-temperature operation die-attachment material, Ag, have received extensive attention in power devices for its excellent thermal conductivity and reliability with high-temperature (over 250°C) applications. At present, sintering silver nanoparticles is commonly used to achieve stable die-attach joint in industry. However, the size effect of nanoparticles makes the preparation and storage of very fine nanoparticles (less than 50 nm) extremely difficult, which can increase the cost of paste. In this paper, we introduce a method for preparing sintered solder with MOD (metal organic decomposition) and commercial Ag nanoparticles, which takes the advantage of Ag nucleation of MOD at low temperature to assist commercial Ag nanoparticles in the paste to achieve lower temperature sintering bonding. We used silver oxalate as a precursor and made it complex with 1, 2-diaminopropane to prepare the MOD solution ink. The MOD ink was utilized as additive at low temperature to assist the connection of nanoparticles in the paste to form a strong joint. The results suggest that shear strength of sintering joint can reach 32.7 MPa at 175°C.

Silver particle free inks display immense superiority and potential over silver nanoparticle based inks in the aspect of synthesis, flexibility and low temperature processing, which has attracted considerable research interest as an alternative for fabricating conductive structures in recent years. Although recent research on silver particle free inks has led to beneficial results, there are still some drawbacks some of the inks are chemically unstable and hence are not suitable for industrial inkjet printing process, although they have good conductivity; while others are cheap in terms of raw material costs but are complicated to make due to the complex synthetic route or using hazardous procedures, or are not compatible with inkjet printing. Therefore, it will be advantageous to develop a stable, cheap and inkjet printable silver particle free ink using a simple synthetic procedure. Alcohols are favorable solvents for silver particle free inks that can provide the ink with essential fluid properties for inkjet printing. However, they have some negative effects on the ink performance due to their physicochemical properties, which should be avoided. In this work, a simple do it yourself silver particle free ink is presented, which shows high chemical stability, low cost and good printability. The ink is formulated via a simple silver oxalate precursor route in alcohols. The fluid property, thermal property, stability and electrical performance of the inks based on different alcohols were investigated and optimized to obtain the final ink for printing on glass and flexible polyimide substrates. The printed Ag features yielded a resistivity of 15.46 amp; 956; amp; 937; cm at a sintering temperature of 180 C, which is equivalent to 10 times bulk silver. Based on a comprehensive assessment, we can offer a low cost, easy to make, reliable and highly competitive ink for flexible printed electronics

19 pags., 14 figs., 8 tabs., The crystal structures and elastic properties of the anhydrous zinc and cadmium oxalates and lead oxalate dihydrate are determined using rigorous first-principles solid-state methods. The three materials are shown to display negative Poisson’s ratios (NPR) and to exhibit the negative linear compressibility (NLC) phenomenon. Anhydrous zinc and cadmium oxalates display NLC for a very wide range of external pressures applied in the direction of minimum compressibility in the ranges − 1.3 to 5.5 GPa and − 1.2 to 2.7 GPa, respectively. The increase of volume in both materials is substantial for pressures larger than 3.6 and 1.8 GPa, and the compressibilities become − 70.1 and − 67.0 TPa for pressures of 5.2 and 2.6 GPa, respectively. The increase of volume is so drastic that these materials become unstable for pressures larger than 5.5 and 2.7 GPa. Lead oxalate dihydrate also displays NLC along the direction of minimum Poisson’s ratio for negative pressures in the range − 0.05 to − 0.08 GPa and undergoes a pressure-induced phase transition for relatively low external pressures of the order of 0.1 GPa. The presence of NPR and NLC phenomena in these three materials together with the previous finding of these phenomena for silver oxalate strongly suggests that other metal oxalate materials could also exhibit an extremely anomalous mechanical behavior., Supercomputer time by the CTI-CSIC center is greatly acknowledged. One of the authors (VT) was supported by the Ministry of Science, Innovation and Universities within the Project FIS2016-77726-C3-1-P.

Copper–silver hybrid conductive inks can combine the advantages of lower cost, better conductivity and long-term stability of the copper or silver ink, which have attracted wide research interest in the development of materials for flexible electronics. Although Cu–Ag nanoparticle based inks, such as Cu–Ag core–shell nanoparticle inks and Cu–Ag bimetallic nanoparticle inks, have already been developed and applied to produce conductive patterns using different deposition methods, they are still not ideal because of the complex and time-consuming synthetic process, low yield and high sintering temperature for good conductivity. In this paper, we report synthesis and characterization of novel self-catalyzed Cu–Ag organic complex inks with reduced sintering temperature via a simple one-step method. The effects of Cu–Ag ratio on the thermal property, stability and electrical performance of the formulated inks were investigated, where the Cu1–Ag1 ink was found to be ideal in terms of cost, conductivity and thermal behavior. The presence of silver oxalate in the copper complex ink was beneficial to the thermal decomposition of the Cu complex and able to decrease the sintering temperature by 30 °C due to the catalytic function of silver, making it more compatible with flexible polymer substrate materials. Meanwhile, the addition of a small amount of silver oxalate could improve the conductivity of the Cu ink. The sintered Cu–Ag films showed favorable conductivity which is comparable to the value of the reported Cu–Ag nano inks but with a lower sintering temperature. The Cu1–Ag1 hybrid ink with self-catalyzing capability is a balanced choice when considering the cost and conductivity.

With the wide application of third-generation semiconductor in power devices, the development of the new material that can satisfy the high-temperature service of die-attach joint has become a significant challenge. Silver has attracted extensive attention for high thermal and electrical conductivity. However, the industrial application of silver has been restricted due to its high melting temperature. In this paper, a novel Ag nanoparticle paste assisted with MOD (metal organic decomposition) was prepared, and a low-temperature Ag-Ag bonding with high strength was obtained. Silver oxalate is synthesized as a silver precursor and complexed with ethylenediamine to form a silver ammonia complex as a metal organic source. The active metal organic source with low decomposition temperature was employed as a bridge among the commercial silver nanoparticle. After sintering at 150 °C for 30 min under certain pressure, the shear strength of sintered bonding joints can reach 17 MPa. The fracture and cross-sectional microstructures of bonded joints exhibited obvious ductile characteristics and compact structure. These results suggest the silver paste with MOD is prone to sinter at a low temperature and can fulfill the requirements of die-attach materials for power device packaging.

International audience; A new process using the selective decomposition of silver oxalate is presented and applied to the production of transparent electrodes on a polymer substrate. It is indeed shown that the silver oxalate Ag2C2O4 can be reduced to the metallic silver state by the focused laser beam of a photolithography machine (λ = 405 nm, spot size 5 µm, power between 3 and 100 mW). Thin lines of silver of width close to 15 µm, for optimized insolation conditions, can thus be directly and easily, formed in a layer of oxalate deposited by spin coating on polycarbonate substrate. Since the metal and the oxalate are of very different chemical natures, the residual oxalate is dissolved by an ammoniacal solution without affecting the metal. The silver conductive lines have a very porous vermicular type microstructure which, however, ensures electrical conductivity. The resistive effects, which result from this not very compact filament organization, can be reduced by simply applying a uniaxial mechanical pressure perpendicular to the plane of the substrate. This operation irreversibly reduces the porosity by crushing the silver strands. One by one-centimeters samples with an electrical resistance of 10 Ω and an optical transparency of 95% (after correcting the effects of the substrate) were thus prepared. Their factor of merit expressed by (Transparency550nm)10 / Rpattern, close to 0.059 Ω−1, is at the state of the art. The selective decomposition of silver oxalates by a laser beam is therefore a very interesting way to easily make transparent conductors made of thin metallic patterns.

Now days, resistance of bacteria to bactericides and antibiotics has increased. Some antimicrobial agents are extremely irritant and toxic. Hence there is a need to find ways to formulate green and less toxic materials. In the present work, a study of synergistic effects of as-synthesised triangular shaped silver nanoparticles and two standard antibiotics, ampicillin and gentamycin, was studied on Staphylococcus Aureus and Pseudomonas Aeruginosa. A green route is taken to synthesise silver nanoparticles using silver oxalate as precursor; tea extract and chitin as capping and stabilizing agents respectively. A grey coloured colloidal solution of silver nanoparticles is obtained. XRD, TEM and UV-visible spectroscopy, are used tocharacterise the as-synthesised silver colloidal solution.

Silver oxalate Ag2C2O4 is an interesting compound from both fundamental and practical viewpoints. Decomposition of Ag2C2O4 results in the formation of metallic silver, whose size and morphology can be tailored for different applications. In this work, we focused on the morphological features of silver that forms upon decomposition of Ag2C2O4 in a spark plasma sintering (SPS) apparatus. While crystals heated in a conventional furnace decompose to produce silver in the form of a pseudomorph, decomposition induced by heating in a SPS chamber at a rate of 30 °C·min-1 via a pressureless process results in the formation of foam-like porous silver. Decomposition of Ag2C2O4 was also carried out under pressure by placing the powder between copper plates and heating the assembly in a SPS die. A feasibility study has shown that Ag2C2O4 powders can be used for joining copper plates in a fast process enabled by the SPS method. Joints formed by the SPS method at 300°C and 13 MPa were formed by silver with 500-nm crystallites; the shear strength of the joints was 45 MPa.

Silver conductive ink using silver oxalate as silver precursor has attracted considerable research interest due to its unique properties. However, silver oxalate has poor dissolvability in organic solvents and high thermal decomposition temperature, the latter is not desirable for pattern formation on some low cost polymer based flexible substrates. In this paper, different kinds of alkylamine were chosen as ligands to formulate silver oxalate inks to address the mentioned issues. The role of amines in silver oxalate based inks was studied in detail. The influence of amine types on thermal property, stability and electrical performance of the formulated silver oxalate inks was investigated. The relationships between them were established and elucidated. The results show that highly conductive silver films with controlled microstructure features can be achieved for low temperature sintering by selection of an appropriate amine as the latter has a strong influence on the decomposition temperature of the formed silver–amine complex and it determines the nucleation and growth of silver particles in the film formation process. The chemical reactions occurring within the ink were also studied. An optimal silver complex ink was prepared by using blended amines as ligands finally, producing a uniform silver film with good quality and favorable conductivity at 150 °C. The results are important for future design of stable and high conductive silver complex inks for practical applications.

Favorable conductivity at low temperature is desirable for flexible electronics technology, where formulation of a suitable ink material is very critical. In this paper, a type of silver organic decomposable ink (10 wt.% silver content) was formulated by using as-prepared silver oxalate and butylamine, producing silver films with good uniformity and conductivity on a polyimide substrate after sintering below 130°C (15.72 μΩ cm) and even at 100°C (36.29 μΩ cm). Silver oxalate powder with good properties and an appropriate solid amine complex with lower decomposition temperature were synthesized, both differing from those reported in the literature. The influence of the factors on the electrical properties of the produced silver films such as sintering temperature and time was studied in detail and the relationship between them was demonstrated.

Metallization-free Ag sinter bonding to Si and SiO2 substrates was achieved via the thermal decomposition of Ag oxalate. Ag oxalate generated atomic-scale Ag through decomposition at approximately 200 °C and transformed into sintered Ag. Ag derived from Ag oxalate successfully bonded to Si substrates through close contact formation with Si surface oxide. Similarly, amorphous and α-quartz SiO2 substrates were directly bonded with Ag. These results indicate that the atomic-scale Ag generated on SiO2 contributed to interface formation over a large area. Moreover, the joints of the bare Si chip and metal substrate showed a maximum shear strength of 29 MPa at a bonding temperature of 250 °C and a bonding pressure of 5 MPa. The in-situ generation of Ag through the decomposition of Ag precursors can facilitate the direct bonding of electronic materials, making the proposed method a promising one for electronics applications.

In the research area of conductive inks for printed electronics, the preparation of conductive circuits generally shows high requirements on the process temperature, process efficiency, electrical conductivity, foldability and so on. In this paper, a new type of Ag complex conductive ink modified by PVAc (poly vinyl acetate) was proposed to enhance the conductivity and foldability of rapidly sintered Ag patterns. The conductive ink was fabricated by mixing silver oxalate as Ag precursor, 1,2-Diaminopropane as complexing reagent, methanol and isopropanol as organic solvents, and a small amount of PVAc as binding agent. Compared to the Ag complex ink without PVAc, the modified ink shows a better sintered microstructure with higher flatness and density after fast sintering at 140 °C–200 °C for 2 min, indicating that the addition of PVAc has a positive effect on the stability of Ag nucleation and microstructure formation. A low resistivity of 5.17 μΩ cm and an improved foldable property can be achieved at 180 °C by sintering the PVAc modified Ag complex ink on PI (polyimide) substrate, which indicates that the proposed ink is promised to be applied in printed circuits and flexible electronics. Keywords: Ag complex ink, PVAc, Low-temperature, Rapid sintering, Foldable

Bi2O2CO3 is a UV-light-driven photocatalyst. Bi2O2CO3 nanoflakes modified with plasmonic Ag nanoparticles (Ag/Bi2O2CO3) were obtained by a hydrothermal method. In the synthetic process, Ag2C2O4 worked as the Ag source and C source for the simultaneous formation of Ag particles and CO[Formula: see text]. The optimum synthesis condition was found at [Formula: see text]C for 16[Formula: see text]h under alkaline condition. The binary heterostructure was then used for degrading 2, 4-Dichlorophenol (2, 4-DCP) and Rhodamine B in visible light, with an efficiency of nearly 80% for 2, 4-DCP and 100% for Rhodamine B after 4[Formula: see text]h and 2[Formula: see text]h reaction, respectively. The binary heterostructure exhibited improved photocatalytic activity compared to that of individual Ag and Bi2O2CO3 due to Surface Plasmon Resonance (SPR) effect of Ag. Meanwhile, after five recycling experiments, Ag/Bi2O2CO3 showed higher photocatalytic activity and lower performance degradation in comparison with the one prepared by photo-reduction of Ag[Formula: see text] on Bi2O2CO3 nanoflakes. This indicated the advantage of one-pot synthetic method. This work is expected to provide an efficient photocatalyst for organic pollutants degradation.

Copper and silver oxalates have been synthesized and were characterized by IR and XRD. Thermal decomposition of the prepared oxalates has been studied experimentally using differential scanning calorimetric (DSC) and thermogravimetry (TG) and the decomposition products were characterized. Topological properties of electron density, bond orders, bond length and bond angle calculations were carried out in the light of the thermal decomposition pathway characteristic for these compounds with the help of density functional theory using LanL2DZ as basis set. All the computational studies were made using Gaussian09W simulation package. The obtained results shed some additional light on the origins of the complex pathway observed during the thermal decomposition process. Global reactive descriptors like vertical ionization potential, vertical electron affinity, electronegativity, electrophilicity, softness, hardness, etc., are calculated in order to analyze the extent of reactivity of the molecules considered. The obtained results from the experiments, support the conclusion that during the thermal decomposition process, copper oxalate decompose to Cu, Cu2O/CuO nanoparticles and CO/CO2, where as the silver oxalate decompose to Ag metal and CO2, the silver metal on exposure to air is transformed to Ag2O, which are in agreement with the theoretical analysis.

9 pags., 7 figs., 1 tab., The crystal structure and mechanical properties of silver oxalate, Ag2C2O4, are determined using first-principles solid-state methods. The set of calculated mechanical properties include the bulk modulus and its pressure derivatives, the Young and shear moduli, the Poisson’s Ratio and the ductility, hardness, and anisotropy indices. Silver oxalate is a highly anisotropic brittle material possessing a small bulk modulus of 9.6 GPa. It displays the negative Poisson’s ratio (NPR) phenomenon, the value of the lowest NPR having a very large magnitude, −1.27. Besides, it exhibits the most extreme form of the negative linear compressibility (NLC) phenomenon found to date. Silver oxalate displays anisotropic NLC for external pressures in the range −0.1 to −2.4 GPa directed along the [010] crystallographic direction and isotropic NLC for isotropic pressures in the range −0.51 to 13.4 GPa. The lowest value of the negative compressibility, −831.9 ± 10 TPa−1, is found for an isotropic pressure of −0.16 GPa. The absolute value of the computed lowest NLC is extremely large, about three times larger than the absolute value of the lowest NLC found so far. The NLC pressure range is also very wide, its width being more than two times the largest range found to date, Supercomputer time by the CTI-CSIC center is greatly acknowledged

Industrial wastewater resulted from textile dyeing process is considered as a big environmental problem. Therefore, recycling of wastewater offers environmental and economic values specially if the materials used are resulted from recycling of other kinds of waste. From this point of view and for the first time this work deals with the study the wastewater recycling by calcium oxide resulted from eggshell recycling. Calcium oxide (CaO) nanocrystals were created by the thermal annealing of chicken egg shell at 1100 °C for 2 h s. Heat treatment at 200 °C in air for 2 h s of the resulted CaO with silver oxalate gave the novel composite, silver nanoparticles loaded calcium oxide (Ag-NPs @ CaO). By applying electronic spectra (UV–Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy with the energy dispersion spectrum analysis (SEM-EDX) and transmittance electronic microscope (TEM), the materials were characterized. The energy band gap was calculated from the equation of Tauc for CaO and Ag-NPs@CaO and measured to be 2.1 and 2 eV, respectively. Indigo carmine (IC) as a model of photocatalytic decolorization was performed using both CaO and Ag@CaO nanoparticles under sunlight exposure. The impacts of various variables such as solution pH, dose quantity, temperature and irradiation time were studied. Both catalysts displayed an effective photocatalytic activity in IC decolorization but Ag@CaO composite displayed a stronger activity than CaO. The percentages of dye degradation were ≈99.21% and 99.45% in case of CaO and Ag@CaO, respectively. The antibacterial efficiency was measured against some Gram-negative and Gram-positive bacteria. Ag@CaO provided powerful weapons against the drug-resistant bacteria. These findings give a promising and economic strategy for all those who are interested in industries which involve dyeing process.

Pulsed electric current can be used for the fast sintering of powders as well as joining of macroobjects. In this work, we brazed copper plates using a silver layer that was formed in situ by the decomposition of a silver oxalate Ag2C2O4 powder placed between the plates. Joining was conducted in the chamber of a Spark Plasma Sintering (SPS) facility with and without a graphite die. In the die-assisted tooling configuration, indirect heating of the assembly from the graphite die carrying electric current occurred until the brazing layer transformed into metallic silver. The passage of electric current through a Cu/Ag2C2O4/Cu stack placed between the electrodes without a die was possible because of the formation of Cu/Cu contacts in the areas free from the Ag2C2O4 particles. Joints that were formed in the die-assisted experiments showed a slightly higher shear strength (45 MPa) in comparison with joints formed without a die (41 MPa). The shear strength of the reference sample (obtained without a die), a stack of copper plates joined without any brazing layer, was only 31 MPa, which indicates a key role of the silver in producing strong bonding between the plates. This study shows that both die-assisted tooling configurations and those without a die can be used for the SPS brazing of materials by the oxalate-derived silver interlayer.

The co-precipitates, Ag2Cu(C2O4)·nH2O, of varying composition [Ag = (0.125, 0.25, 0.5, 1 and 2) %] have been prepared, identified and characterized by means of IR, XRD and SEM. The decomposition kinetics was studied by thermogravimetry at four different heating rates: 5, 10, 15 and 20 K min−1. Decompositions of the mixed oxalates were all complex exothermic processes with resemblance to the exothermic reaction of copper oxalate. The activation energies of the thermal decomposition were calculated using model-free equations; KAS, FWO, Vyazovkin and Tang methods and the values are found to be compatible with each other. The activation energy values of the decomposition reactions obtained from FWO and Vyazovkin are slightly higher than that obtained from other methods. The kinetic analysis of copper–silver oxalates prepared shows a decrease in average activation energy with increase in the concentration of silver oxalate. E a is found to increase with extent of conversion, which indicates the complexity of the reaction.

We have developed a new green method for deposition of silver nanoparticles (Ag NPs) on TiO2. Insoluble solid silver oxalate (Ag2C2O4) is dissolved in an aqueous solution of N,N-dimethyl-1,3-diaminopropane. The alkylamine-activated silver oxalate undergoes TiO2-catalyzed thermal decomposition at low temperatures ( 90%). The catalytic activity of the prepared Ag NPs on the TiO2 is evaluated via hydrogenation of 4-nitrophenol.

High-aspect-ratio Ag nano- and microplates have been produced via an inhomogeneous system, i.e., coordination-polymer fine crystals of silver oxalate, Ag2(C2O4), suspended in an aqueous solution co...

A solid silver-ligand complex, μ-oxolato-bis(ethylenediaminesilver(I)), was developed for formulating particle-free conductive metal–organic decomposition (MOD) inkjet inks. The complex comprises both a high molar silver content and solubility in inkjet compatible polar solvents. An aqueous ink formulation with 29.5 wt % silver content was developed and inkjet printed onto glass, polyethylene terephthalate, and polyimide substrates. A new hybrid thermal-photonic curing approach resulting in substantially improved electrical properties and substrate adhesion is presented. Silver conductive traces were measured to have bulk resistivity of 4.26 × 10–8 Ω m, which is 2.7 times that of bulk silver. One-pot complex synthesis yielded an easily isolated, and stable, solid product that can be formulated when needed thereby improving shelf life.

International audience; Silver oxalate Ag2C2O4, was already proposed for soldering applications, due to the formation when it is decomposed by a heat treatment, of highly sinterable silver nanoparticles. When slowly decomposed at low temperature (125 °C), the oxalate leads however to silver nanoparticles isolated from each other. As soon as these nanoparticles are formed, the magnetic susceptibility at room temperature increases from -3.14 10-7 emu.Oe-1.g-1 (silver oxalate) up to -1.92 10-7 emu.Oe-1.g-1 (metallic silver). At the end of the oxalate decomposition, the conventional diamagnetic behaviour of bulk silver, is observed from room temperature to 80 K. A diamagnetic-paramagnetic transition is however revealed below 80 K leading at 2 K, to silver nanoparticles with a positive magnetic susceptibility. This original behaviour, compared to the one of bulk silver, can be ascribed to the nanometric size of the metallic particles.

A deep understanding of the metallic silver catalysts formation process on oxide support and the formation mechanism is of great scientific and practical meaning for exploring better catalyst preparing procedures. Herein the thermal decomposition process of supported silver catalyst with silver oxalate as the silver precursor in the presence of ethylenediamine and ethanolamine is carefully investigated by employing a variety of characterization techniques including thermal analysis, in situ diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, and X-ray diffraction. The formation mechanism of supported silver particles was revealed. Results showed that formation of metallic silver begins at about 100 o C and activation process is essentially complete below 145 o C. Formation of silver was accompanied by decomposition of oxalate group and removal of organic amines. Catalytic performance tests using the epoxidation of ethylene as a probe reaction showed that rapid activation (for 5 minutes) at a relatively low temperature (170 o C) afforded materials with optimum catalytic performance, since higher activation

In the present work, a comparative study of antibacterial activity and synergistic effects of triangular silver nanoparticles in combination with two standard antibiotics is discussed for Staphylococcus aureus and Pseudomonas aeruginosa. A green route was developed to synthesise silver nanoparticles in which silver oxalate was taken as precursor, black tea leaves extract as surfactant and chitin as a stabilizing agent. A grey coloured colloidal solution of silver nanoparticles was obtained which was characterized by using various techniques like X-ray diffractometer (XRD), transmission electron microscopy (TEM) and UV-visible spectroscopy. Anti-bacterial studies gave approximately equal inhibition zones for both the combinations which states that silver nanoparticles are to be equally effective and synergistic effects were clearly observed in case of P. aeruginosa.

The density of heat source at the impact–friction contacts of silver oxalate particles was calculated based on a heat Ag2C2O4 decomposition. The obtained density of the heat source of the chemical reaction was comparable with the density of dry friction source in order of magnitude.

This work presents a new route to obtain a highly conductive silver solder (with thermal conductivity around 100 W/m.K) by thermal decomposition of a silver oxalate precursor at moderate temperature (

A simple, precise, rapid, and low-cost conductometric method for determination of naftidrofuryl oxalate, propafenone HCl and sotalol HCl in pure form and in pharmaceutical formulations using silver nitrate has been described. The method is based on the precipitation of oxalate or chloride ions coming from the cited drugs with silver ions, yielding silver oxalate or silver chloride and the conductance of the solution is measured as a function of the volume of titrant. The studied drugs were evaluated in double distilled water in the range of 1-15 mg. Various experimental conditions were established and results obtained showed good recoveries with relative standard deviation of 0.909, 0.955 and 0.983 for naftidrofuryl, propafenone and sotalol, respectively. The proposed procedures were applied successfully to the analysis of these drugs in their pharmaceutical formulations. Results were favorably comparable to the official or reference methods.

Monodisperse, crystalline silver nanoparticles are synthesized by sonolytically assisted decomposition of silver oxalate and oleate precursors in dibenzylether. Oleic acid and oleylamine are used as capping agents. The diameters of the obtained particles vary from 6 to 10 nm depending on the sonification time and the precursor material. The particles are stable in non-polar media. A 2D and 3D assembly of the as-prepared nanoparticles is observed. Particle sizes and dispersities are characterized by transmission electron microscopy and image analysis. The decomposition characteristics of the different precursor compounds are investigated using UV–Vis spectroscopy and thermogravimetry.

The diffusion of volatiles into silica glasses was studied by sorption experiments in argon gas pressure vessels at 2 kbar and temperatures from 521 to 1097 °C. In the experiments either Ar and H 2 O (AH series, samples in open containers), or CO 2 and H 2 O (CH series, samples in closed noble metal capsules with silver oxalate added as source for CO 2 ) could exchange between the fluid and the glasses. Both sample assemblies were run simultaneously to enable direct comparison of diffusion data. Profiles were recorded on sections perpendicular to the initial surfaces by electron microprobe (Ar) and FTIR spectroscopy (CO 2 and H 2 O). Ar diffusion is systematically slower by 0.17 log units in average in water-rich silica glass (∼ 0.05 wt.% H 2 O, Suprasil ® ) than in water-poor silica glasses ( 2 O, Infrasil ® and Herasil ® ) while the activation energy for argon diffusion agrees within error. This effect is attributed to partial closure of doorways for argon in the silicate network by the formation of hydroxyl groups. CO 2 is dissolved only as molecular species in silica glasses and its diffusivity is about the same as that of argon, similar as found for rhyolitic glasses. Dissolved H 2 O was detected in the run products exclusively in form of silanol groups. The H 2 O profiles show systematic deviations from error function shape. The shape of the profiles could originate from either a positive correlation of water diffusivity to water content or a continuous decrease in water fugacity in the fluid. H 2 O was only a minor component in the fluids and the condition of an infinite reservoir was not necessarily always ensured during the whole run. Assuming negligible decrease of water fugacity during experiment, diffusion coefficients of H 2 O ( D H2O ) were determined by a Boltzmann–Matano analysis. The data are consistent with D H2O being proportional to the concentration of dissolved water.