Iron Foil Research Articles

Concentrated Chloride Electrolyte Enabling SEI for Fe Metal Anode

Iron is one of the most abundant metal elements in the Earth’s crust and has been widely used worldwide since ancient times. Due to this natural abundance and well-established mass production methods, iron is a promising candidate as a battery electrode for cost-effective large-scale energy storage systems. Edison’s Ni-Fe battery, invented in 1900, used an alkaline electrolyte without ferrous or ferric ions that eventually limited its anode design using iron oxide. More recent Fe redox flow batteries and the newly suggested Fe-ion batteries that use an acidic electrolyte containing ferrous ions (Fe2+) can utilize iron foil as an anode. Combining iron foil with Fe2+ electrolyte enables a simple design and faster kinetics on the anode side. However, introducing acidic electrolytes accelerates hydrogen evolution reaction (HER) on the iron surface. Severe HER affects cell performance in various ways, including lower Coulombic efficiency (CE), drying out of the electrolyte by water consumption, and precipitation of Fe2+ ions due to increased pH of the electrolyte. In this work, a concentrated chloride-based electrolyte was introduced to Fe-ion batteries to suppress HER and achieve a high-CE Fe2+/Fe electrode. With the help of nonpolar [ZnCl4]2- which enables low-polarity organic additives to be soluble in the aqueous solution, an organic solid electrolyte interface (SEI) can be formed on top of the electrode while plating iron. Fe anode protected by the SEI shows a noticeable decrease in HER during cycling, which leads to higher CE of more than 98% and twice longer cycle life.

Three-dimensional surface analysis of iron-based materials using synchrotron Mössbauer source

A novel three-dimensional surface analysis system for iron-based solid materials has been developed. This system is composed of a synchrotron Mössbauer source, an X-ray focusing device, a precision stage, a gas flow proportional counter for conversion electron measurements, and multiple multichannel scalers. The performance was evidenced by determining the spatial distribution of the iron oxide abundance on a laser-ablated iron foil surface. This system can be widely utilized as a powerful analytical tool in steel science for corrosion, welding, and laser surface modification.

Image Quality and Radiation Exposure in Abdominal Angiography: A Head-to-Head Comparison of Conventional Detector-Dose-Driven Versus Contrast-to-Noise Ratio-Driven Exposure Control at Various Source-to-Image Receptor Distances and Collimations in a Pilot Phantom and Animal Study.

This phantom and animal pilot study aimed to compare image quality and radiation exposure between detector-dose-driven exposure control (DEC) and contrast-to-noise ratio (CNR)-driven exposure control (CEC) as functions of source-to-image receptor distance (SID) and collimation. First, an iron foil simulated a guide wire in a stack of polymethyl methacrylate and aluminum plates representing patient thicknesses of 15, 25, and 35 cm. Fluoroscopic images were acquired using 5 SIDs ranging from 100 to 130 cm and 2 collimations (full field of view, collimated field of view: 6 × 6 cm). The iron foil CNRs were calculated, and radiation doses in terms of air kerma rate were obtained and assessed using a multivariate regression. Second, 5 angiographic scenarios were created in 2 anesthetized pigs. Fluoroscopic images were acquired at 2 SIDs (110 and 130 cm) and both collimations. Two blinded experienced readers compared image quality to the reference image using full field of view at an SID of 110 cm. Air kerma rate was obtained and compared using t tests. Using DEC, both CNR and air kerma rate increased significantly at longer SID and collimation below the air kerma rate limit. When using CEC, CNR was significantly less dependent of SID, collimation, and patient thickness. Air kerma rate decreased at longer SID and tighter collimation. After reaching the air kerma rate limit, CEC behaved similarly to DEC. In the animal study using DEC, image quality and air kerma rate increased with longer SID and collimation ( P < 0.005). Using CEC, image quality was not significantly different than using longer SID or tighter collimation. Air kerma rate was not significantly different at longer SID but lower using collimation ( P = 0.012). CEC maintains the image quality with varying SID and collimation stricter than DEC, does not increase the air kerma rate at longer SID and reduces it with tighter collimation. After reaching the air kerma rate limit, CEC and DEC perform similarly.

Deposition of FeOOH Layer on Ultrathin Hematite Nanoflakes to Promote Photoelectrochemical Water Splitting.

Hematite is one of the most promising photoanode materials for the study of photoelectrochemical (PEC) water splitting because of its ideal bandgap with sufficient visible light absorption and stability in alkaline electrolytes. However, owing to the intrinsically high electron-hole recombination, the PEC performance of hematite is still far below that expected. The efficient charge separation can be achieved via growth of FeOOH on hematite photoanode. In this study, hematite nanostructures were successfully grown on the surface of iron foil by the simple immersion deposition method and thermal oxidation treatment. Furthermore, cocatalyst FeOOH was successfully added to the hematite nanostructure surface to improve charge separation and charge transfer, and thus promote the photoelectrochemical water splitting. By utilizing the FeOOH overlayer as a cocatalyst, the photocurrent density of hematite exhibited a substantial 86% increase under 1.5 VRHE, while the onset potential showed an apparent shift towards the cathodic direction. This can be ascribed to the high reaction area for the nanostructured morphology and high electrocatalytic activity of FeOOH that enhanced the amount of photogenerated holes and accelerated the kinetics of water splitting.

Tin-doped NiFe2O4 nanoblocks grown on an iron foil for efficient and stable water splitting at large current densities.

Developing low-cost and self-supported bifunctional catalysts for highly efficient water splitting devices is of great significance. Herein, different from previously reported NiFe2O4-based electrocatalysts, we have grown nano-NiFe2O4 directly onto the iron foil (IF) surface and in situ introduced Sn4+ into NiFe2O4. The resulting experimental phenomena confirmed that the as-synthesized Sn-NiFe2O4/IF can deliver large-current densities (>1000 mA cm-2) during oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) processes at a low overpotential. The needed overpotentials at the current density of 10 and 1000 mA cm-2 are 231 and 368 mV for OER and 57 and 439 mV for HER, respectively. Additionally, when applied for the two-electrode water splitting, the corresponding needed voltage for Sn-NiFe2O4/IF at the current density of 10 mA cm-2 was only 1.56 V, which was comparable to the commercial Pt/C-RuO2/IF electrode. Thus, the introduced Sn4+ greatly enhanced the electrocatalytic property of Sn-NiFe2O4/IF, resulting in a superior bifunctional catalyst that can be applied for large-scale hydrogen production.

Effect of crystal structure on K shell binding energy of lead, mercury and tungsten using bremsstrahlung radiation

The K shell binding energies of lead, mercury, and tungsten in their pure elemental form and in some of their compounds have been measured for the first time by adopting a novel method. The method involves a weak beta source, an external bremsstrahlung converter, element and compound targets, and a high-resolution, high-purity germanium detector coupled to 16K multichannel analyzer. Continuous external bremsstrahlung photons produced by the interaction of beta particles from a 90Sr-90Y radioactive source with an iron foil are allowed to pass through the elemental and compound targets of lead, mercury, and tungsten. The spectrum of transmitted external bremsstrahlung photons is measured with a high-resolution high purity germanium detector spectrometer. The transmitted spectrum shows a sudden drop in intensity at K shell binding energy of the target. Such a sudden drop, which is due to the onset of the K shell photoelectric effect, has been used to determine the K shell binding energies. It has been investigated that the shifts in the K shell binding energies due to chemical environment of lead, mercury, and tungsten atoms is attributed to crystal structure.

Principal Component Analysis (PCA) unravels spectral components present in XPS spectra of complex oxide films on iron foil

Principal component analysis (PCA), as applied to the processing of the complex X-ray photoelectron spectroscopy (XPS) lineshapes, is discussed. PCA analysis example is provided of complex native iron oxide films on Fe foil XPS spectra further modified by argon and helium ion beams. Abstract PCA components are derived from Fe 2p, O 1 s and C 1 s regions leading to the assignments of surface (oxy)hydroxide, Fe2O3, FeO and Fe metal, as corroborated by the corresponding elemental quantification profiles. Detailed mathematical concepts behind PCA analysis of spectra data are provided.

Dynamic fracture processes in hydrogen embrittled iron

Mechanistic understanding of hydrogen embrittlement is critical to the transport and storage of hydrogen as a sustainable fuel. Experimental observation of dynamic fracture processes in hydrogen environments has been challenging. Here, in-situ transmission X-ray microscopy is used to image polycrystalline iron foils that are concurrently strained and electrochemically charged with hydrogen. Using this technique, voids and microcracks down to ∼30 nm in size are identified at or near the crack tip and tracked as strain is increased. We observe both hydrogen-induced transgranular failure and hydrogen-induced intergranular failure with distinct fracture processes. We find that transgranular fracture occurs through the formation of sharp branched structures at the main crack tip that are reminiscent of slip band formation. This is followed by void growth and coalescence, and interaction with secondary cracks that lead to propagation of the main crack. Intergranular fracture is found to occur through void coalescence along grain boundaries, along with significant secondary cracking near the crack tip. The crack growth rate is greater for void-mediated intergranular failure than for slip-mediated transgranular failure. Additionally, the removal of hydrogen results in recovered ductility for a crack initially propagated under hydrogen charging.

Ultra-low oxygen, liquid sample cell for in situ synchrotron-based small-wide angle scattering (SAXS-WAXS)

Here, we report the design and successful implementation of an ultra-low oxygen sample cell for use on the SAXS-WAXS (small-wide angle x-ray scattering) beamline I22 at DIAMOND. The rigorous exclusion of oxygen is found to require double jacketing with purge gas throughout the entire system, pipework, pumps, and the sample cell itself. This particularly includes a “double-window” arrangement at the sample location to accommodate the very tight geometrical restrictions of the sample position. The in situ cell design also requires the additional complexity of heating the sample/solution and real-time electrochemical measurements. We demonstrate the successful implementation of this arrangement with real-time in situ characterization of an iron foil corrosion evolving under the “sweet-scale environment,” very anoxic conditions common, in particular, commercial situations. The formation of iron carbonate, siderite, rather than iron oxide, indicates that our system is oxygen free down very low levels (&amp;lt;35 ppb at 80 °C).

Influence of groundwater composition on the reductive precipitation of U(VI) on corroding iron foil surfaces

In order to assess the disposal of spent nuclear fuel in a deep geological nuclear waste repository, the interactions between U(VI) and corroded iron present in the canister material are of importance. It is important to correctly model the fate of the oxidatively dissolved uranium in order to correctly estimate radium releases from the canister in the long term. The release of radionuclides into the environment depends on the dissolution of the UO2 matrix which is dependent on the redox conditions at the fuel surface. The effect of metallic iron on the reduction of U(VI) was studied under anoxic conditions using synthetic groundwaters with different compositions, chosen to investigate the influence of calcium-uranyl-carbonato complexes on the thermodynamics and kinetics of U(VI) reduction on anoxically corroding iron. The corrosion products formed on the iron surface were investigated using SEM-EDS and XPS to identify elemental composition and oxidation states of uranium and iron on the surface. The iron foils efficiently reduced U(VI) to U(IV) causing its significant sorption and precipitation on the iron foil surfaces in the form of U(IV).

Assessment of Corrosion Protection Performance of FeOOH/Fe3O4/C Composite Coatings Formed In Situ on the Surface of Fe Metal in Air-Saturated 3.5 wt.% NaCl Solution

The purpose of this work is to evaluate the corrosion-inhibition behavior of deposited carbon and some iron-oxide hybrid coatings which derived from the in situ deposition method on the surface of Fe foil. Various contents of precursor methane gas were deposited over a mild iron foil substrate and formed different composites. It was found that the incorporation of C into the Fe matrix led to a thin film on the surface of the matrix and produced an anti-corrosion effect. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and potentiometric tests were used to compare the corrosion behaviors of the films in air-saturated 3.5 wt.% NaCl solution. According to the results, Fe-oxide- and C-composite-coated iron foil has a much higher corrosion resistance than the raw blank sample without the addition of C. Generally, the corrosion charge transfer resistance of one kind of iron oxide coated with carbon layers of several nanometers was enhanced up to 28,379 times (Rct changes from 1487 Ω cm2 to 4.22 × 107 Ω cm2), which is the biggest improvement so far. The maximum protection efficiency was obtained for the in situ grown coating prepared by 10 and 15 sccm CH4 precursor gas (eta = 100%). In conclusion, an iron oxide and carbon composite was found to be a great candidate for applications in the corrosion-resistance area.

Magneto-Tactile Sensor Based on a Commercial Polyurethane Sponge.

In this paper, we present the procedure for fabricating a new magneto-tactile sensor (MTS) based on a low-cost commercial polyurethane sponge, including the experimental test configuration, the experimental process, and a description of the mechanisms that lead to obtaining the MTS and its characteristics. It is shown that by using a polyurethane sponge, microparticles of carbonyl iron, ethanol, and copper foil with electroconductive adhesive, we can obtain a high-performance and low-cost MTS. With the experimental assembly described in this paper, the variation in time of the electrical capacity of the MTS was measured in the presence of a deforming force field, a magnetic field, and a magnetic field superimposed over a deformation field. It is shown that, by using an external magnetic field, the sensitivity of the MTS can be increased. Using the magnetic dipole model and linear elasticity approximation, the qualitative mechanisms leading to the reported results are described in detail.

Accurate determination of the electron spin polarization in magnetized iron and nickel foils for Møller polarimetry

The Møller polarimeter in Hall A at Jefferson Lab in Newport News, VA, has provided reliable measurements of electron beam polarization for the past two decades. Past experiments have typically required polarimetry at the 1% level of absolute uncertainty which the Møller polarimeter has delivered. However, the upcoming proposed experimental program including MOLLER and SoLID have stringent requirements on beam polarimetry precision at the level of 0.4% (The MOLLER Collaboration, 2014; The SoLID collaboration, 2019), requiring a systematic re-examination of all the contributing uncertainties.Møller polarimetry uses the double polarized scattering asymmetry of a polarized electron beam on a target with polarized atomic electrons. The target is a ferromagnetic material magnetized to align the spins in a given direction. In Hall A, the target is a pure iron foil aligned perpendicular to the beam and magnetized out of plane parallel or antiparallel to the beam direction. The acceptance of the detector is engineered to collect scattered electrons close to 90° in the center of mass frame where the analyzing power is a maximum (-7/9).One of the leading systematic errors comes from determination of the target foil polarization. Polarization of a magnetically saturated target foil requires knowledge of both the saturation magnetization and g′, the electron g-factor which includes components from both spin and orbital angular momentum from which the spin fraction of magnetization is determined. Target foil polarization has been previously addressed in a 1997 publication “A precise target for Møller polarimetry” by de Bever et al. (1997) at a level of precision sufficient for experiments up to this point. Several shortcomings with the previous published value require revisiting the result prior to MOLLER. This paper utilizes the existing world data to provide a best estimate for target polarization for both nickel and iron foils including uncertainties in magnetization, high-field and temperature dependence, and fractional contribution to magnetization from orbital effects. We determine the foil electron spin polarization at 294 K to be 0.08020 ± 0.00018 (@4 T applied field) for iron and 0.018845±0.000053 (@2 T applied field) for nickel. We conclude with a brief discussion of additional systematic uncertainties to Møller polarimetry using this technique.

A novel H-type linear permanent magnet eddy current brake

To improve the braking force of the Linear Permanent Magnet Eddy Current Brakes (LPMECB) under a large Air Gap (AG) length, this paper presents a novel structure of the LPMECB, named H-type Linear Permanent Magnet Eddy Current Brake (H-type LPMECB). To begin with, the analytical model of the LPMECB is established by using the equivalent magnetic circuit method, and it is found that the AG reluctance is greater than that of the other parts of the LPMECB. Based on this, a novel H-type LPMECB is proposed in order to compensate the influence of the AG. The H-type LPMECB adds Iron Foils (IFs) in the AG. These IFs are rectangular sheets made of pure iron. Furthermore, the finite element model of the H-type LPMECB is established to optimize the geometry parameter of the IFs, then the braking performance of the H-type LPMECB is measured. The simulations show that the optimal geometry parameter of the IFs of the H-type LPMECB is 0.25 ∗ L, and the braking performance of the H-type LPMECB is superior to that of the LPMECB, around three times. Finally, experiments were conducted, which validated the simulations.

Rechargeable Iron-Ion Battery Using a Pure Ionic Liquid Electrolyte.

A rechargeable iron-ion battery (Fe-ion battery) has been fabricated in our laboratory using a pure ionic liquid electrolyte. Magnetic ionic liquids of 1-butyl-3-methylimidazolium tetrachloroferrate (BmimFeCl4) and 1-methyl-3-octylimidazolium tetrachloroferrate (OmimFeCl4) are synthesized and utilized as electrolytes in this work. The chemical structure of the two ionic liquids (ILs) is investigated using Raman analysis. In addition, the physical and thermal stability properties of the ionic liquid (IL) BmimFeCl4, including density, viscosity, melting point, and decomposition temperature, are investigated using a density meter, viscosity meter, differential scanning calorimeter, and thermogravimetric analyzer. Moreover, the electrochemical properties, including electrochemical window, and ionic conductivity of the IL BmimFeCl4 are investigated using an electrochemical instrument and a conductivity meter. It is found that the magnetic IL BmimFeCl4 has good physical and electrochemical properties to be utilized as an electrolyte for iron-ion battery fabrication. Iron-containing materials, including pure iron foil, carbon-coated iron nanoparticles, and iron powder, are used as a cathode in the Fe-ion battery. The anode of the Fe-ion battery is graphite. Electrochemical properties of full cells are investigated, including cyclic voltammetry curves and specific charge–discharge capacity. The Fe-ion battery is a unique rechargeable ion battery with magnetic ions. In addition, pure IL BmimFeCl4 is utilized as an electrolyte in this Fe-ion battery. IL BmimFeCl4 is stable and almost nonvolatile. Therefore, an Fe-ion battery with a pure IL electrolyte is safer than that with an organic electrolyte. An Fe-ion battery using a pure IL electrolyte is a promising battery with many potential applications.

Magnetite‐Free Sn‐Doped Hematite Nanoflake Layers for Enhanced Photoelectrochemical Water Splitting

In the present work, we report on a preparation strategy for hematite phase-pure photoanodes consisting of Sn-doped hematite nanoflakes/hematite thin film bilayer nanostructure (Sn-HB). This approach is based on a two-step annealing process of pure iron films deposited on FTO substrates by advanced magnetron sputtering. While the high density hematite ultrathin nanoflakes (HNs) with detrimental iron oxide layers (Fe 3 O 4 and/or FeO) are generated during the first annealing step at 400 °C for two hours, the second thermal treatment at 800 °C for 15 minutes oxidises all the undesired iron oxide phases to a photoactive hematite layer as well as is providing efficient Sn doping of a drop-casted SnCl 4 in order to increase the conductivity. The optimized Sn-HB shows an ~11 times higher photocurrent density (0.71 mA/cm 2 at 1.23 V RHE ) compared with a reference hematite photoanode produced from iron foil under the same conditions.

Experimental phase equilibria study and thermodynamic modelling of the PbO-“FeO”-SiO2-ZnO, PbO-“FeO”-SiO2-Al2O3 and PbO-“FeO”-SiO2-MgO systems in equilibrium with metallic Pb and Fe

Phase equilibria of the PbO-“FeO”-SiO2-ZnO, PbO-“FeO”-SiO2-Al2O3 and PbO-“FeO”-SiO2-MgO slags with liquid Pb metal, solid or liquid Fe metal and solid oxides (cristobalite and tridymite SiO2, willemite (Zn,Fe)2SiO4, wustite (Fe,Al)O1+x, spinel (Fe,Al)3O4, olivine Fe2SiO4, corundum (Al,Fe)2O3, mullite Al6Si2O13 and pyroxene (Mg,Fe)SiO3) were investigated at 1125–1670 °C. These conditions correspond to the minimum solubility of PbO in slag in presence of Pb and Fe metals at reducing conditions and represent the limit of lead smelting and slag cleaning process. High-temperature equilibration on silica, corundum or iron foil substrates, followed by quenching and direct measurement of Pb, Fe, Si, Zn, Al and Mg concentrations in the liquid and solid phases with the electron probe X-ray microanalysis (EPMA) was used. Present data can be used to improve the thermodynamic models for all phases in this system.

Obtaining Hematite Nanoflakes Substrates By Electrochemical Anodization of Iron Foil and Heat Treatment

Synthesizing nanostructure’s importance is due to the applications that these materials can offer. Electrochemical anodization is considered an easily accessible technique; variables control allows to obtain diverse morphologies (from nanopores to nanotubes). The main reaction is oxide – reduction, it produces a protective oxide layer to metals and promotes different morphologies. Anodized iron sheets were carried out, with a concentration of 1.2 M of NH4F in a solution of ethylene glycol and water. The anodization time (5, 10, 15, and 20 minutes) was varied to a constant potential of 30 Volts. The substrates were subjected to annealing of 450 °C for 2 hours to obtain the hematite phase, it was observed that the morphology changed to nanoflakes. With Raman spectroscopy and X-ray diffraction, phase mixing (hematite and magnetite) was determined. The bandgap of 2.15 eV was determined with diffuse reflectance

Comparison of a contrast-to-noise ratio-driven exposure control and a regular detector dose-driven exposure control in abdominal imaging in a clinical angiography system.

The first purpose of this phantom study was to verify whether a contrast-to-noise ratio (CNR)-driven exposure control (CEC) can maintain target CNR in angiography more precisely compared to a conventional detector dose-driven exposure control (DEC). The second purpose was to estimate the difference between incident air kerma produced by CEC and DEC when both exposure controls reach the same CNR. A standardized 3D-printed phantom with an iron foil and a cavity, filled with iodinated contrast material, was developed to measure CNR using different image acquisition settings. This phantom was placed into a stack of polymethylmethacrylate and aluminum plates, simulating a patient equivalent thickness (PET) of 2.5-40cm. Images were acquired using fluoroscopy and digital radiography modes with CEC using one image quality level and four image quality gradients and DEC having three different detector dose levels. The spatial frequency weighted CNR and incident air kerma were determined. The differences in incident air kerma between DEC and CEC were estimated. When using DEC, CNR decreased continuously with increasing attenuation, while CEC within physical limits maintained a predefined CNR level. Furthermore, CEC could be parameterized to deliver the CNR as a predefined function of PET. To provide a given CNR level, CEC used equal or lower air kerma than DEC. The mean estimated incident air kerma of CEC compared to DEC was between 3% (PET 20cm) and 40% (PET 27.5cm) lower in fluoroscopy and between 1% (PET 20cm) and 55% (PET 2.5cm) lower in digital radiography while maintaining CNR. Within physical and legislative limits, the CEC allows for a flexible adjustment of the CNR as a function of PET. Thus, the CEC enables task-dependent examination protocols with predefined image quality in order to easier achieve the as low as reasonably achievable principle. CEC required equal or lower incident air kerma than DEC to provide similar CNR, which allows for a substantial reduction of skin radiation dose in these situations.

Formation of Dense and High-Aspect-Ratio Iron Oxide Nanowires by Water Vapor-Assisted Thermal Oxidation and Their Cr(VI) Adsorption Properties.

Coral-like and nanowire (NW) iron oxide nanostructures were produced at 700 and 800 °C, respectively, through thermal oxidation of iron foils in air- and water vapor-assisted conditions. Water vapor-assisted thermal oxidation at 800 °C for 2 h resulted in the formation of highly crystalline α-Fe2O3 NWs with good foil surface coverage, and we propose that their formation was due to a stress-driven surface diffusion mechanism. The Cr(VI) adsorption property of an aqueous solution on α-Fe2O3 NWs was also evaluated after a contact time of 90 min. The NWs had a removal efficiency of 97% in a 225 mg/L Cr(VI) solution (pH 2, 25 °C). The kinetic characteristic of the adsorption was fitted to a pseudo-second-order kinetic model, and isothermal studies indicated that the α-Fe2O3 NWs exhibited an adsorption capacity of 66.26 mg/g. We also investigated and postulated a mechanism of the Cr(VI) adsorption in an aqueous solution of α-Fe2O3 NWs.