Pb Foils Research Articles

Identifying Problematic Phase Transformations in Pb Foil Anodes for Sodium-Ion Batteries

Group IVA elements have aroused attention in sodium-ion batteries (SIBs) due to their Na-storage capability. Among them, Pb is less explored perhaps due to its perceived risks, but its long-standing success in Pb-acid batteries should not be neglected. Together with the well-established recycling procedures, the merits of Pb warrant further investigations as a practical SIB anode. In this work, four intermetallic phases are detected during electrochemical sodiation of Pb, which yields a capacity of ∼460 mAh·g−1 (∼1167 mAh·cm−3) upon the formation of Na15Pb4. When pursuing full capacities, the electrode stops functioning after only 3–4 cycles largely due to electrode physical damage. The reversibility of each phase transformation pair is then assessed to explore the origins of capacity fading. The NaPb/Na9Pb4 transformation shows the worst stability, consistent with the observed structural damage (e.g., cracks and voids). Through bypassing the problematic phase transformations using a partial cycling protocol, the stability of Pb foil anodes is improved, giving 20 cycles with 85% capacity retention. Considering other factors are unoptimized, it is suggested that the Pb-based anodes should not be fully eliminated from the future roadmap of SIBs, as the prospective merits can create value to ensure the management of such materials of concern.

Impact of Scattering Foil Composition on Electron Energy Distribution in a Clinical Linear Accelerator Modified for FLASH Radiotherapy: A Monte Carlo Study.

This study investigates how scattering foil materials and sampling holder placement affect electron energy distribution in electron beams from a modified medical linear accelerator for FLASH radiotherapy. We analyze electron energy spectra at various positions-ionization chamber, mirror, and jaw-to evaluate the impact of Cu, Pb-Cu, Pb, and Ta foils. Our findings show that close proximity to the source intensifies the dependence of electron energy distribution on foil material, enabling precise beam control through material selection. Monte Carlo simulations are effective for designing foils to achieve desired energy distributions. Moving the sampling holder farther from the source reduces foil material influence, promoting more uniform energy spreads, particularly in the 0.5-10 MeV range for 12 MeV electron beams. These insights emphasize the critical role of tailored material selection and sampling holder positioning in optimizing electron energy distribution and fluence intensity for FLASH radiotherapy research, benefiting both experimental design and clinical applications.

Effect of diffusion of elements on microstructural, mechanical, and machining characteristics of Al7075/ZnAl4 functionally graded material with and without Ag and Pb interface

The current experimental work uses die casting, a liquid processing method, to create functionally graded material (FGM). To reduce the production of undesired intermetallic compounds, the FGM samples were created both with and without interfacing foil during the procedure. Mechanical properties including impact strength and microhardness were examined throughout the manufactured sample's cross-section. In addition, the interfacial bonding of FGM samples with and without an interacting foil was determined by estimating the shear strength. Analysis of the samples using X-ray diffraction (XRD) and scanning electron microscopy (SEM) reveals the existence of compounds in the sample as well as the diffusion of Al and Zn particles from one side to the other. Compared to the FGM without foil, it is observed that the diffusion rate at the interface is regulated when the foil is present. In addition, it was found that, in contrast to pb foil, the inclusion of Ag foil limited the rate at which particles could move from one side to the other. Additionally, machining investigations are carried out at varying depths on both sides of the sample in the direction of the interface with the assistance of electric discharge machining.

Optimized cyclotron production of 211At: The challenge of 210Po-characterization

The yield of 211At is currently limited by the restriction of the incident He2+-beam energy of the 209Bi(α,2n)211At reaction to ≈28 MeV avoiding the co-production of 210At with its daughter 210Po through 209Bi(α,3n)210At. In parallel, 210Po is directly produced as well through the 209Bi(α,x)210Po reaction at a energies as low as 26.7 MeV. Cross-sectional data predict a significant increase of the 211At-yield at higher energies indicating that this approach warrants optimization. The strategy of using higher energies means that potential solutions to handle 210Po during production, target processing and labelling, including the potential 210Po-related toxicity in (pre-) clinical studies have to be studied. Here we present the results of the 210Po quantification after a non-destructive target characterization.Two 25 μm thick Bi targets were irradiated at the Scanditronix MC 32, Rigshospitalet Copenhagen at 28.8 MeV and 29.8 MeV. For both targets the theoretical yield of 211At, 210At and the directly produced 210Po was estimated in a 25 layered 1 μm Bi model using the available cross-sectional data. The 211At and 210At yields were measured with a HPGe-detector 30 min post EOB. After sufficient decay Pb foils and a210Po calibration source were used to calibrate an iQID α-camera and an AMBER α-spectrometer prior to the non-destructive quantification of 210Po.Calculations predict a 28% and 1600% increased yield per μA of respectively 210At and 211At for targets irradiated at 28.8 and 29.8 MeV respectively. At the same time the 210Po activity increased by 350% up to a total activity of 24.14 kBq from which 60% is attributable to the direct reaction.Measured 211At and 210At activities show an increase of 49% and 1900% per μA for the 29.8 MeV target whereas quantification of 210Po with both α-detection systems validates the predicted activities.The results obtained in this study confirm a significantly increased yield of 211At at higher incident He2+- beam energies but also indicate the importance of directly produced 210Po, which impacts the assessment of 210Po prior to target processing.

Characterization of a Nb-Pb composite target

A thin Nb target on a Pb backing was fabricated using the rolling technique. In the present work, the characterization of the sample has been carried out using various techniques to study the surface morphology, crystallography, elemental analysis, thickness and electrical conductivity useful for the intended use of the target prepared. The thin Nb target was analyzed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Rutherford back-scattering spectroscopy (RBS) techniques. The uniform and smooth surface of the sample was confirmed by SEM imaging. The presence of oxygen in the EDS spectra and peaks corresponding to crystal planes of PbO2 in the XRD spectrum confirms the oxidation of Pb foil. The XRD spectrum shows clear peaks corresponding to (011), (002), (112) crystal planes of pure Nb. The thickness of the thin Nb foil measured using the RBS techniques was found to be 0.8 mg/cm2. The current(I)-voltage(V) curve (relationship between the current flowing through an electronic device and the applied voltage across its terminals) at room temperature for the Pb and Nb/Pb foils was plotted and showed linear relationship between applied voltage and current flowing through the target foil. The measured electrical conductivity indicates an enhancement of 35.9 % for Nb/Pb foil relative to the conductivity measured for the Pb foil.

A facility for the characterisation of planar multilayer structures with preliminary niobium results

The maximum accelerating gradient of superconducting radio frequency cavities are currently reaching their theoretical limits, due to the magnetic field entering the superconductor in the form of vortices. To overcome these limits, thin film coated superconducting materials are required, however these need to be tested to optimise their properties. A system has been designed, built, and commissioned at Daresbury Laboratory that applies a local DC magnetic field parallel to the surface, from one side of a sample, similar to that in cavity operation. A magnetic flux density (up to 600 mT) is generated parallel to the sample surface in the 2 mm gap of a C-shaped ferrite yoke. Two Hall probe sensors are used to measure both the applied and penetrated magnetic field. The system operates in a cryogen free environment, with a minimum temperature of approximately 2.6 K. A Pb foil has been used to characterise the system, and determine how the sample size affects the results. Nb thin film samples have been tested for varying thickness to determine how the depth effects the field of full flux penetration, . The design, operation, methods of analysis and first results of this facility will be reported in this paper.

Measurement of Thermal Diffusivity of Thin Film in Thickness Direction Using an Ordinary Dielectric Film as the Sensor

Accurate thermal parameters of thin films are beneficial for the engineering thermal design and thermal management of electronic devices to improve the operating stability and prolong service life. In this article, a novel method for measuring the thermal diffusivity of thin films is proposed based on the thermal pulse method (TPM) for mapping space charge distribution, whose thermal response current is strongly determined by the temperature profiles within thin film. A multi-layer thin film structure is adopted, in which the tested film layer is thermally coupled on the dielectric film substrate with thermal parameters known. The thermal pulse by laser pulse excites the tested film and then penetrates into the dielectric film substrate. By analyzing the thermal response current of the dielectric film substrate, one can deduce the temperature profiles in both layers and therefore the thermal diffusivity of the tested film. The proposed method can determine the thermal diffusivity of both insulating and electric conduction films with the thickness tens of micrometers in through thickness direction. The obtained values of the thermal diffusivity of polyimide (PI), bi-oriented polypropylene (BOPP), polyethylene 2,6-naphthalate (PEN), tin(Sn) foil, and lead (Pb) foil are well consistent with the data provided in the literatures. By the analyzing heat boundary conditions, the interface thermal resistance between the tested film and the dielectric film substrate can be also determined at the same time.

Novel characterization of lead-based micro-alloys for battery applications

Although Pb-alloy acid batteries have been incorporated in vehicles for decades, a significant gap exists in the scientific understanding of minor alloying elements in the complex Pb-alloy grid materials. The aim of this research is to close this gap by using modern analytical techniques to examine the effects associated with adding minor alloying elements, less than 100 ppm, in Pb-alloy grid materials during isothermal holds and thermal cycling at relatively high temperatures. In this study, pure Pb, Pb-Bi, and Pb-Ba foils are examined using high-energy synchrotron radiation X-ray diffraction measurements during in situ isothermal holding at 85 °C and thermal cycling from RT to 85°C to analyze the grain inhibition and phase evolution. It is observed that Ba inhibits grain growth while Bi does not, when compared to pure Pb. Furthermore, no obvious phase evolution in any of the three cases is observed. After the synchrotron radiation X-ray diffraction measurements, the three materials are examined ex situ using scanning electron microscopy to verify the results. Additionally, baseline sulfation studies were performed in a solution of approximately 5 M H2SO4 and Pb-Bi and Pb-Ba were added to the electrochemical cell to undergo cyclic voltammetry.

Influence of intensive parameters and assemblies on friction evolution during piston-cylinder experiments

Abstract Piston-cylinder assemblies exhibit inhomogeneous pressure distributions and biases compared to the theoretical pressure applied to the hydraulic press because of the thermal and mechanical properties of the assembly components. Whereas these effects can partially be corrected by conventional calibration, systematic quantification of friction values remain very sparse and results vary greatly among previous studies. We performed an experimental study to investigate the behavior of the most common cell assemblies, i.e., talc [Mg3Si4O10(OH)2], NaCl, and BaCO3, during piston-cylinder experiments to estimate the effects of pressure, temperature, run duration, assembly size, and assembly materials on friction values. Our study demonstrates that friction decreases with time and also partially depends on temperature but does not depend on pressure. We determined that friction decreases from 24 to 17% as temperature increases from 900 to 1300 °C when using talc cells, indicating a friction decrease of ~2% per 100 °C increase for 24 h experiments. In contrast, friction becomes independent of time above 1300 °C. Moreover, at a fixed temperature of 900 °C, friction decreases from 29% in 6 h runs to 21% in 48 h runs, corresponding to a decrease of friction of 0.2% per hour. Similar results obtained with NaCl cell assemblies suggest that friction is constant within error, from 8% in 9 h runs to 5% in 24 h runs. At 900 °C, possible steady-state friction values are only reached after at least 48 h, indicating that friction should be considered a variable for shorter experiments. We establish that assembly materials (and their associated thermomechanical properties) influence the friction correction more than the dimensions of the assembly parts. Finally, we show that the use of polytetrafluoroethylene film instead of conventional Pb foil does not modify friction but significantly reduces the force required for sample extraction, thus increasing the lifetime of the carbide core, which in turn enhances experimental reproducibility.

FLUKA simulations and benchmark measurements of the YAP(Ce) scintillators installed on the VESUVIO spectrometer

We present experimental results and FLUKA Monte-Carlo simulations reproducing the counting efficiency and the energy resolution of the cerium-activated yttrium-aluminium-perovskite photon detectors installed on the VESUVIO neutron spectrometer at the ISIS Pulsed Neutron and Muon Source. In particular, we investigate the performance of these detectors in the energy range between 100 keV and 300 keV. In this range, the γ-emission of the 197Au resonant analyser foils, installed on VESUVIO to select the energy of scattered neutrons, is predominant. Such photons are currently discarded by the low-level discrimination threshold of the acquisition electronics set to 600 keV. Here, we model the detector crystals for a series of thickness values, and we discuss how 2-cm-thick crystals would significantly reduce the acquisition times with respect to the 6-mm-thick crystals employed at present. Additionally, we show how the signal-to-background ratio can be substantially enhanced by shielding the scintillators with 0.5-mm-thick Pb foils. We finally discuss the improved detection performance on a model sample of interest for Cultural-Heritage applications.

Tracking the fungus‐assisted biocorrosion of lead metal by Raman imaging and scanning electron microscopy technique

AbstractFungi play a significant role in biological corrosion of metal materials. We studied the biocorrosion of lead foils under incubation of Aspergillus niger (A. niger). Multiple techniques, for example, scanning electron microscopy (SEM), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and Raman imaging and scanning electron microscopy (RISE), were applied in this study. SEM confirmed the normal growth of the fungus on Pb foil surface, either above or under the solid medium surface. In addition, SEM‐energy dispersive spectrometer confirmed the formation of the secondary Pb mineral particles after incubation, which had variable morphologies. DRIFT was able to show changes of compounds formed on the surface of Pb foils. However, it cannot exactly identify the mineral phase. RISE technology offered both morphological and spectral information of the formed Pb mineral. Three dominant Raman peaks at ~1,440, ~1,480, and ~1,590 cm−1 indicated that the secondary mineral was lead oxalate. Raman mapping further demonstrated the distribution of Pb oxalate architecture. This study first applied RISE to investigate the biocorrosion of metals by fungi.

Modeling the primary source intensity distribution: reconstruction and inter-comparison of six Varian TrueBeam sources

The primary source size is one of the most important beam model parameters in small photon fields. In this work we apply a recently suggested reconstruction technique to characterize the primary source of 6 Varian TrueBeam (TB) linacs. A series of photon fluence profile measurements were performed on 6 Varian TB linacs in the crossplane and inplane orientation using radiochromic film in air and a 2 mm Pb foil as a build-up layer. An image reconstruction algorithm was then applied, based on the maximum likelihood expectation-maximization (MLEM) algorithm, to estimate the source distribution. The method iteratively ray-traces photons from the source plane to the measurement plane to extract source profile corrections. The technique was first benchmarked using a Monte Carlo (MC) model of a Varian TrueBeam with known input Gaussian source sizes. The robustness of the suggested technique was also tested by randomly sampling different combinations of source and field size values and repeating the reconstruction. At the MC benchmarking stage the MLEM reconstruction algorithm was capable of reproducing the Gaussian shape with a RMSE less than 4.0%, while the reconstructed source size (FWHM) and field size were determined with an accuracy level of 0.14 mm and 0.10 mm respectively. Experimentally, the reconstructed TB sources presented FWHM values between 1.02–1.5 mm (–0.18 mm) and 1.08–1.42 mm (–0.13 mm) in the crossplane and inplane orientations respectively. All TB sources studied in this work can be considered symmetric within uncertainties with the exception of one. The source distribution presented systematic deviations from a Gaussian distribution mostly in the lower tail region. Multi-parameter functional forms, such as Pearson VII or double Gaussian presented improvements in modeling the source in this region, but increase the model complexity. The reconstructed sources measured in this work can serve as reference values for commissioning beam models in small fields and set upper and lower thresholds values of the expected source size for a TB linac.

Depth profiles of production yields ofnatPb(p, xn)206,205,204,203,202Bi reactions using 100-MeV proton beam

In this study, results of the experimental study on the depth profiles of production yields of 206,205,204,203,202 Bi radio-nuclei in the natural Pb target irradiated by a 100-MeV proton beam are presented. Irradiation was performed at proton linac facility (KOMAC) in Korea. The target, irradiated by 100-MeV protons, was arranged in a stack consisting of natural Pb, Al, Au foils and Pb plates. The proton beam intensity was determined by activation analysis method using 27 Al(p, 3p1n) 24 Na, 197 Au(p, p1n) 196 Au, and 197 Au(p, p3n) 194 Au monitor reactions and also using dosimetry method by a Gafchromic film. The production yields of produced Bi radio-nuclei in the natural Pb foils and monitor reactions were measured by gamma-ray spectroscopy. Monte Carlo simulations were performed by FLUKA, PHITS, and MCNPX codes and compared with the measurements in order to verify validity of physical models and nuclear data libraries in the Monte Carlo codes. A fairly good agreement was observed between the present experimental data and the simulations by FLUKA, PHITS, and MCNPX. However, physical models and the nuclear data relevant to the end of range of protons in the codes need to be improved.

Oxygen modulation of flexible PbS/Pb Schottky junction PEC cells with improved photoelectric performance

Flexible photoelectric devices are emerging as a new class of photovoltaic cells. In this study, lead (Pb) foil was used as a flexible substrate to grow in situ lead sulfide (PbS) film with good uniformity and adhesion by a solvothermal elemental direct reaction, resulting in a PbS/Pb Schottky junction formed naturally between the PbS film and underlying Pb foil. We found that the photocurrent response of the photoelectrochemical (PEC) cell was greatly improved through a facile oxygen (O2)-modulation-based post-processing technique. O2 could decompose the organic residue and oxidize the Pb at the interface between the PbS film and Pb foils. Different characterization techniques, including thermogravimetric analysis, differential scanning calorimetry, x-ray diffraction, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, the change in transient photocurrent density (Jp) with time (t), dark current–voltage (I–V) and absorption spectra were applied to get a full understanding of the O2 modulation effect. The oxidization treatment of the PbS film could regulate the flow of charge carriers to reduce their recombination, leading to photoresponse enhancement for the PEC cells. In particular, the process could modulate the tunneling current and interface states to optimize dark I–V characteristics. In addition, the magnitude of the barrier height can be tuned by O2 modulation, which was explained by theoretical analysis and calculation. We also demonstrated that the in situ formed PbS film has outstanding adhesion on the flexible Pb substrate. Our film synthesis method and post O2-modulation design as well as the corresponding device assembly may provide a novel perspective to the flexible PCE-cell-related research.

Laser lap welding quality of steel/aluminum dissimilar metal joint and its electronic simulations

This paper presents an effect of alloying elements on brittleness of FeAl phase. Microstructure and mechanical properties of laser welding joints with/without Cu or Pb foil in an overlap steel-on-aluminum configuration are investigated. A good agreement between the experimental results and theoretical predictions for the improved mechanical properties can be seen. In the case of adding Pb foil, there is good combination between the metal of the weld pool and the base aluminum metals, welding defects are uneven, and the layer thickness of intermetallic compounds (IMCs) reduces compared with that of no foil; in addition, Mg2Pb phase is formed at the steel/aluminum interface, and the structure of Mg2Pb is more stable than that of FeAl. Thus, the formation of IMCs is inhibited; hence, mechanical properties of the welding joint are significantly improved.

Controlling H+ vs CO2 Reduction Selectivity on Pb Electrodes

Nanocrystalline Pb films prepared by reducing PbO2 precursors have up to 700-fold lower H+ reduction activity than polycrystalline Pb foil electrodes but maintain the ability to reduce CO2. As a result, these “oxide-derived” Pb (OD–Pb) electrodes have higher Faradaic efficiency for CO2 reduction to HCO2– in aqueous solutions with almost no competitive H+ reduction. Even with very low CO2 concentrations in N2-saturated NaHCO3 solution, OD–Pb converts CO2 derived from HCO3– decomposition to HCO2– with almost quantitative Faradaic efficiency while Pb foil has less than 10% efficiency. Electrokinetic data suggest that the difference in selectivity between the two electrodes is caused by a difference in the coverage of a surface layer—likely a metastable Pb oxide—that is passivating for H+ reduction but active for CO2 reduction.

The production of residual nuclides in Pb irradiated by 400 MeV/u carbon ions

The experiment was performed by irradiating a Pb foil with 400MeV/u carbon beam at the HIRFL-CSR in Lanzhou, China. The experimental data was acquired by the off-line γ-spectroscopy method. 32 radioactive residual nuclides had been observed and their cross sections were determined. The measured results were compared with the results simulated by Monte Carlo code MCNPX2.7.0. The comparison shows that the simulated cross sections were underestimated for the fragments from A=20 to 41 and A=110 to 175. By fitting the measured and simulated cross sections to Rudstams semi-empirical formula, it was found that the charge distribution of products was asymmetric for the residual nuclides with a high mass number.

Flexible quantum dot-sensitized solar cells with improved efficiencies based on woven titanium wires

Uniform zinc oxide (ZnO) nanosheet arrays were grown on woven titanium wires using a low temperature hydrothermal method. Photoanodes were prepared by depositing CdS and CdSe quantum dots onto the ZnO nanosheet arrays by a successive ionic layer adsorption and reaction (SILAR) method. Solar cells were assembled using these nanostructured photoanodes and their photovoltaic performance was characterized. The effect of using SILAR cycles for the deposition of quantum dots on the performance of these nanostructured solar cells was investigated systematically. The overall light-to-electricity conversion efficiency of 0.98% was achieved under 100 mW cm−2 illumination for flexible CdS/CdSe co-sensitized solar cells using conventional Pt foils as counter electrodes. To further improve the performance of the flexible solar cells, PbS and Cu2S counter electrodes based on Pb and Cu foils were fabricated. The best conversion efficiencies of flexible CdS/CdSe co-sensitized solar cells using Cu2S and PbS counter electrodes were 3.4% and 2.5%, which demonstrated a significant enhancement in values for short circuit current, open circuit voltage, and fill factor compared to those obtained with the commonly used Pt and Au electrodes.

Effect of Brazing Flux Pb on Microstructure and Mechanical Property of CMT Weld-Brazed Lap Joint of 5052 Aluminum Alloy to Galvanized Q235 Steel

5052 aluminum alloy and galvanized Q235 steel sheets with thickness of 1mm were lap welded/brazed by cold metal transfer technology (CMT) with ER4043 as the filler wire and Pb foil as the brazing flux. Scanning electron microscope (SEM), microscope with super-depth, X-ray diffraction (XRD), electronic universal tensile testing machine and hardness tester were employed to study the microstructure and mechanical properties of the joint. The results indicate that Pb foil effectively improved the mechanical properties of the joint with tensile strength up to 160Mpa which is higher than that of the joint without the brazing flux of Pb foil. Intermetallic compound (IMC) layer in the brazing joint unequally distributed in the interface of aluminum alloy and galvanized steel. The thickness of IMC layer was about 1~3.5um. The main phases of the IMC layer were FeAl and AlFe6Si. Fine equiaxial crystals existed in the weld metal while columnar crystals existed in the fusion zone of aluminum alloy. The hardness of fusion zone was higher than base metal while the hardness of heat affected zone was lower than base metal. In most case, the lap joint was broken in the junction of base metal and fusion zone.

A method of fast-neutron imaging with energy threshold based on an imaging plate

A method of fast-neutron imaging with energy threshold is presented in this paper, which is based on an imaging plate covered with a metal foil and a hydrogen-rich foil in order to reduce the contribution from the neutrons with a lower energy such as the scattering neutrons from samples. The method is capable of effectively reducing the relative sensitivity of the imaging detector to neutrons with energies in a certain energy range. The 14 MeV neutron imaging structure with an energy threshold is designed, and it includes a TR imaging plate covered with an about 150 m Pb foil and a 500 m polyethylene foil. The calculated results show that for the present structure its sensitivity to the neutrons with smaller than 8 MeV is reduced by 30% less than that to the neutrons with 14 MeV. The fast-neutron radiography is validated experimentally on a DT neutron generator (K400). The results indicate that the neutron imaging structure with an energy threshold is available to remove the edge enhancement effect introduced by scattering neutrons from samples.