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Accurately acquiring crucial data on tube furnaces and real-time temperature monitoring of different temperature zones is vital for material synthesis technology in production. However, it is difficult to achieve real-time monitoring of the temperature field of tube furnaces with existing technology. Here, we proposed a method to fabricate silver (Ag) resistance temperature detectors (RTDs) based on a blade-coating process directly on the surface of a quartz ring, which enables precise positioning and real-time temperature monitoring of tube furnaces within 100–600 °C range. The Ag RTDs exhibited outstanding electrical properties, featuring a temperature coefficient of resistance (TCR) of 2854 ppm/°C, an accuracy of 1.8% FS (full scale), and a resistance drift rate of 0.05%/h over 6 h at 600 °C. These features ensured accurate and stable temperature measurement at high temperatures. For demonstration purposes, an array comprising four Ag RTDs was installed in a tube furnace. The measured average temperature gradient in the central region of the tube furnace was 5.7 °C/mm. Furthermore, successful real-time monitoring of temperature during the alloy sintering process revealed approximately a 20-fold difference in resistivity for silver-palladium alloys sintered at various positions within the tubular furnace. The proposed strategy offers a promising approach for real-time temperature monitoring of tube furnaces. [ABSTRACT FROM AUTHOR]

Selected results of investigations focused on the changes to some mechanical properties of palladium and several palladium-based alloys caused by exposure to hydrogen have been collected and presented. The findings indicate that the mechanical properties of pure palladium are highly susceptible to alteration upon exposure to hydrogen. In the cases of alloying palladium with silver and copper, the alloys, as compared to palladium, appear to resist changes to mechanical properties. In the case of alloying palladium with manganese, the interesting order–disorder phenomenon plays an important role on the effects of hydrogen exposure on their mechanical properties. [ABSTRACT FROM AUTHOR]

Silver (Ag), palladium (Pd), and bimetallic silver-palladium (Ag-Pd) coatings were deposited on a mild steel surface by the co-sputtering method. The aim was to investigate and compare the corrosion behavior of Ag-Pd nano-coatings as well as the effect of increasing the weight ratio of Ag in the Ag-Pd alloy in the 3.5% NaCl solution. The corrosion protection performance and barrier protection properties were monitored using electrochemical impedance spectroscopy and potentiodynamic polarization. The surface of the coatings was characterized by scanning electron microscopy, atomic force microscopy, energy-dispersive x-ray spectroscopy, and field-emission scanning electron microscopy. The results of corrosion measurements revealed a relationship between silver wt.% and corrosion resistance. Also, all the coatings had protective effects and barrier properties on the mild steel in the corrosive solution. The best efficiency was observed in silver monometallic coating with 54 nm thickness. [ABSTRACT FROM AUTHOR]

Highly dispersed bimetallic AgPd nanoparticles with different composition have been successfully deposited on the metal-organic frameworks (ZIF-8) by using a simple liquid impregnation method. The resultant catalysts are composition dependent toward dehydrogenation of formic acid, while Ag 18 Pd 82 @ZIF-8 exhibits exceedingly high catalytic activity, with the turnover frequency (TOF) value of 580 h −1 , and 100% hydrogen selectivity at 80 °C. [ABSTRACT FROM AUTHOR]

Silver-palladium alloys have various industrial applications, such as in hydrogen permeation and hydrogen storage materials. The objective of the present study is to determine experimentally the thermodynamic properties of solid state silver-palladium alloys in low temperatures. Thermodynamic measurements of silver-palladium alloys have been performed over a temperature range of 450-750 K by the electromotive force method with superionic conductor AgI as the solid electrolyte. The activity and partial molar Gibbs energy of silver were obtained for Ag-Pd alloys over the whole composition range, and the thermodynamic properties of palladium were calculated using the Gibbs-Duhem equation. The results show that activities of silver exhibit fairly large negative deviations over most of the composition range, and the activities of palladium are characterized by both negative and positive deviations from the ideal Raoultian behavior. The results also show the minimum integral enthalpy of mixing of Ag-Pd alloys to locate at around 60 at.% Ag. [ABSTRACT FROM AUTHOR]

Abstract: The mechanism of the oxidation of glycerol to dihydroxyacetone over Pd–Ag catalysts was discussed. Characterization results suggest that the metal composition of the surface of the crystalline Pd–Ag alloy particles is almost the same as the bulk composition. The synergetic effects of Pd and Ag appear on the oxidation of the secondary OH group of vic-diols. The reaction order with respect to glycerol concentration over Pd–Ag/C was zero, suggesting the strong interaction between glycerol and the catalyst surface. The reaction order with respect to O2 pressure was 0.4, suggesting that the rate-determining step is the reaction involving oxygen species. These reaction trends and characterization results support the mechanism where the terminal OH group of glycerol is adsorbed on the Ag site and the neighboring secondary OH group (CH–OH) is attacked by the oxygen species dissociatively adsorbed on the Pd site. [Copyright &y& Elsevier]

Abstract: Thin PdAg alloy membranes with 20–25% Ag are being developed for hydrogen separation technology. Despite many investigations on such membranes as well as representative experimental and theoretical model systems, unresolved issues remain concerning the effect of the alloy surface structure and composition on adsorption and vice versa. Therefore, the interaction between hydrogen, carbon monoxide or oxygen with the surface of a PdAg model alloy was studied using periodic self-consistent density functional theory (DFT-GGA) calculations. In particular, the adsorption structure, coverage dependence and possible adsorption-induced segregation phenomena were addressed using Pd3Ag(111) model surfaces with varying degrees of surface segregation. In agreement with previous experimental and theoretical investigations, we predict Ag surface termination to be energetically favorable in vacuum. The segregation of Ag is then reversed upon adsorption of H, CO or O. For these adsorbates, the binding is strongest on Pd three-fold hollow sites, and hence complete Pd termination is favored at high coverage of H or CO, while 25% Ag may remain under oxygen because of the lower O-saturation coverage. CO adsorption provides a somewhat stronger driving force for Pd segregation when compared to H, and this may have implications with respect to permeation properties of PdAg alloy surfaces. Our predictions for high coverage are particularly relevant in underlining the importance of segregation phenomena to the hydrogen transport properties of thin PdAg alloy membranes. [Copyright &y& Elsevier]

Abstract: The existing assessment of thermodynamic and phase equilibrium data in the Ag–Pd system was revised on the basis of calorimetric data for liquid Ag–Pd alloys published recently in the literature and on new determination of liquidus and solidus temperatures and activity data for Ag in liquid phase, using differential scanning calorimetry (DSC) coupled with Knudsen cell mass spectrometry (KC/MS). A substantially narrower liquid/fcc two-phase field in phase diagram as well as new non-ideal activity data were revealed. [ABSTRACT FROM AUTHOR]

We have used IR spectroscopy of adsorbed CO to study the effect of the method for preparation of silver-palladium catalysts on a TiO2 substrate and exposure to an oxidizing or reducing gaseous atmosphere on the state of Ag and Pd centers. We have shown that as a result of the metal-support interaction, the reducibility of the Ag and Pd particles is increased, which leads to a change in their adsorption and catalytic properties. [ABSTRACT FROM AUTHOR]