Compact Layer Research Articles

Zn–Al with NO2− as a corrosion inhibitor epoxy-coated carbon steel under artificial atmospheric conditions

This study evaluated Zn–Al–NO2− layered double hydroxide as a corrosion inhibitor in a high-thickness epoxy resin coating (200 µm). The layered double hydroxide was tested in a NaCl solution, using electrochemical impedance spectroscopy. The formed oxides were analysed by X-ray diffraction and energy dispersive X-ray spectroscopy. The corrosion resistance of the epoxy coating (with and without layered double hydroxide) was analysed by electrochemical impedance spectroscopy after exposure to a NaCl solution, salt spray, or a weather-O-meter chamber in a simulated atmospheric environment. The electrochemical impedance spectroscopy measurements for the free layered double hydroxide in a NaCl solution revealed that layered double hydroxide prompted the formation of a compact, protective, and insoluble oxide layer on the carbon steel surface. The Cl− permeability through the epoxy resin film was 5.88 times lower for the film containing layered double hydroxide than for the control. The layered double hydroxide was added to the epoxy coating at a 5 wt-% to evaluate the behaviour of the coating in aggressive environments. The entry of aggressive ions was controlled by the ability of the layered double hydroxide to capture them and release the corrosion inhibitors. Thus, the layered double hydroxide worked as a trap for these aggressive ions and enhanced the performance of the coating. Therefore, a layered double hydroxide addition could benefit a high-thickness coating exposed to an aggressive environment and UV radiation.

Electrospun Fiber‐Based Tubular Structures as 3D Scaffolds to Generate In Vitro Models for Small Intestine

AbstractRecently, in vitro models emerge as valuable tools in biomedical research by enabling the investigation of complex physiological processes in a controlled environment, replicating some traits of interest of the biological tissues. This study focuses on the development of tubular polymeric scaffolds, made of electrospun fibers, aimed to generate three‐dimensional (3D) in vitro intestinal models resembling the lumen of the gut. Polycaprolactone (PCL) and polyacrylonitrile (PAN) are used to produce tightly arranged ultrafine fiber meshes via electrospinning in the form of continuous tubular structures, mimicking the basement membrane on which the epithelial barrier is formed. Morphological, physical, mechanical, and piezoelectric properties of the PCL and PAN tubular scaffolds are investigated. They are cultured with Caco‐2 cells using different biological coatings (i.e., collagen, gelatin, and fibrin) and their capability of promoting a compact epithelial layer is assessed. PCL and PAN scaffolds show 42% and 50% porosity, respectively, with pore diameters and size suitable to impede cell penetration, thus promoting an intestinal epithelial barrier formation. Even if both polymeric structures allow Caco‐2 cell adhesion, PAN fiber meshes best suit many requirements needed by this model, including highest mechanical strength upon expansion, porosity and piezoelectric properties, along with the lowest pore size.

Electrical insulation properties in a cold plasma of alumina coating for the in-vessel stabilizing shell of the RFX-mod2 fusion device

This paper presents the results of experimental tests on samples made of copper coated with alumina layer, performed to assess the reliability of its dielectric properties for applications in the low temperature plasma at the edge of a fusion device. The cue of the study was related to the plasma facing components of the RFX-mod2 fusion device (Marrelli et al., 2019, Peruzzo et al., 2023, Peruzzo et al., 2019), devoted to the experimental study of the magnetic confinement of fusion plasmas in a variety of configurations, including the reversed-field pinch and the tokamak. In RFX-mod2 an in-vacuum copper shell for the passive stabilization of MHD modes will surround the plasma. To avoid potentially harmful electrical discharges, which could be induced by rapid transients of the plasma current, this structure must be covered with an electrically insulating layer. For RFX-mod2 an alumina coating was chosen, whose dielectric properties have been tested both in air and in the presence of weakly ionized plasma. Electrical tests, conducted on copper samples with alumina deposits of about 100μm thickness, revealed that the ceramic layer has a high electrical resistance value in air (>1GΩ), but electrical discharges can occur in presence of a weakly ionized plasma, depending on compactness and porosity of the alumina layer, causing local melting of the alumina and expulsion of copper droplets from the substrate. Scanning Electron Microscope (SEM) analyses revealed that in the failed samples the ceramic layer was irregular and rough, with interconnected cavities and cracks, which could reduce its effective thickness and explain the dielectric breakdown at relatively low voltages (<400V). The analyses also showed that samples with a more compact layer present a higher dielectric strength in the presence of the plasma, highlighting that compactness and porosity play crucial roles in ensuring good insulation for materials in a plasma. This study led the definition of the requirements for the insulating coating of the plasma facing components of the RFX-mod2 fusion machine, however the results can be useful for other fusion and non-fusion plasma applications requiring electrical insulation, which can span from industrial devices to spacecrafts.

Anticorrosion mechanism of epoxy coating containing mesoporous resorcinol-formaldehyde hollow nanosphere loaded with 8-Hydroxyquinolin

Mesoporous resorcinol-formaldehyde hollow nanosphere (MRFHN) with erythrocyte like shape was prepared successfully. The average diameter, shell thickness, and specific area of MRFHN are 223 nm, 42 nm, and 73.2 m2/g, respectively. The average loading capacity of 8-Hydroxyquinoline (8-HQ) in MRFHN is 33 % and the sucked 8-HQ can release continuously from MRFHN. MRFHN loaded with 8-HQ (MRFHN@8-HQ) was introduced into epoxy coating to enhance its anticorrosion performance. The results show that epoxy coating pigmented with MRFHN@8-HQ has a higher anticorrosion performance than neat epoxy coating. Especially, epoxy coating containing 4 wt% of MRFHN@8-HQ presents the best anticorrosion performance and self-healing function, and its coating resistance is still maintained at 109 Ω cm2 even after 50-day immersion in 3.5 wt% NaCl solution. Meanwhile, the scratch on coating surface is covered by a thin layer of 8-HQ which can prevent the AA2024 aluminum alloy from corrosion even after 50-day neutral salt spray test. 8-HQ can release from MRFHN and form a compact inhibiting layer on AA2024 aluminum alloy surface, thus the corrosion of AA2024 aluminum alloy is suppressed effectively. MRFHN@8-HQ can be used as a high performance anticorrosion pigment to give epoxy coating a long term protection.

Friction and wear properties of D-gun sprayed CrFeNiAl0.3Ti0.3-Ag-SrSO4 high entropy alloy matrix self-lubricating coating at elevated temperature

CrFeNiAl0.3Ti0.3-10 wt% Ag-(10−30) wt% SrSO4 high entropy alloy matrix self-lubricating coatings were fabricated using detonation spray technique and tribological characteristics of CrFeNiAl0.3Ti0.3-10 wt% Ag-(10−30) wt% SrSO4 coatings were explored from 25 to 1000 °C. The Ag and SrSO4 lubricants have good compatibility with CrFeNiAl0.3Ti0.3 matrix phase. The bond strength and hardness of CrFeNiAl0.3Ti0.3-Ag-SrSO4 coatings are 30 ∼ 65 MPa and 461 ∼ 535 HV, respectively. Meanwhile this coating exhibited good tribological performance across the wide temperature range and achieved the lowest friction coefficients of 0.29 ∼ 0.49 and wear rates of 2.68 ∼ 11.82 × 10−5 mm3/Nm when SrSO4 content is 10 wt%. Between 25 and 600 °C, SrSO4 and Ag lubricants, can effortlessly create complete lubricating films, preventing three-body wear and plastic deformation. At 800 and 1000 ℃, SrSO4 inflicts a significant impact on the formation of the oxide tribo-layer. When SrSO4 content is 10 wt%, it is feasible to form a compacted oxide layer containing SrCrO4, SrAl2O4 and SrTiO3, reducing the friction and wear. With further increasing SrSO4 content to 20 wt% and 30 wt%, the excessive SrSO4 leads to a detrimental on the compactness of oxide tribo-layer, increasing the friction and wear.

How local electric field regulates C–C coupling at a single nanocavity in electrocatalytic CO2 reduction

C–C coupling is of utmost importance in the electrocatalytic reduction of CO2, as it governs the selectivity of diverse product formation. Nevertheless, the difficulties to directly observe C–C coupling pathways at a specific nanocavity hinder the advances in catalysts and electrolyzer design for efficient high-value hydrocarbon production. Here we develop a nano-confined Raman technology to elucidate the influence of the local electric field on the evolution of C–C coupling intermediates. Through precise adjustments to the Debye length in nanocavities of a copper catalyst, the overlapping of electrical double layers drives a transition in the C–C coupling pathway at a specific nanocavity from *CHO–*CO coupling to the direct dimerization of *CO species. Experimental evidence and simulations validate that a reduced potential drop across the compact layer promotes a higher yield of CO and promotes the direct dimerization of *CO species. Our findings provide insights for the development of highly selective catalyst materials tailored to promote specific products.

Investigating the effect of Y3+/La3+ co-dopant on Ba site of BaSnO3 as an efficient photoanode for dye sensitized solar cell application

This study aims to improve the performance of barium stannate (PBS) based photoanode by co-doping with rare earth elements (Y3+ and La3+) and optimizing charge transport in the mesoporous TiO2 (meso-TiO2) as compact layer at the FTO interface. Employing Y3+ and La3+ dopant into BaSnO3 (YLB) at the FTO/meso-TiO2/YLB interface enhances light absorption and minimizes charge recombination. The resulting DSSC device, utilizing a meso-TiO2/YLB3 photoanode (PBS-3% of Y3+/La3+), achieves an efficiency of 3.79 %, with a high current density of 8.04 mA/cm2, a fill factor of 64.76 % and an open circuit voltage of 0.73 V. The synergistic effect of dopant and compact layer treatment purposefully improves photon and charge collection, enhancing overall device performance and reducing recombination at the interface. Consequently, the introduction of a compact layer-treated co-doped PBS photoanode emerges as a promising alternative for a charge transport layer in DSSC.

Inorganic salts released from polypyrrole nanocapsules on compact TiO2 layer for highly efficient inorganic CsPbI3-type perovskite solar cells

The compact TiO2 serves as a crucial electron transport layer (ETL) for fabricating high-efficiency CsPbI3 solar cells. Modifying TiO2 with inorganic ions is regarded as a simple and effective method to optimize the band energy level, eliminate interface defects, and enhance the crystallinity of the CsPbI3 film. However, inorganic ions risk being washed away by perovskite solvents such as DMF and DMSO. In this work, core–shell inorganic salt (LiCl, NaCl, ZnCl2)@polypyrrole nanocapsules (PPy NCPs) were fabricated as a buffer layer at the interface of TiO2/CsPbI3 layer. The inorganic salts are released from PPy NCPs during the annealing process of the CsPbI3 precursor film, thereby preventing them from being washed away by the DMF/DMSO solvents. Compared to NaCl@PPy NCPs-TiO2, ZnCl2@PPy NCPs-TiO2, and pristine TiO2 films, the LiCl@PPy NCPs-TiO2 exhibited the best electron conductivity and highest Fermi level. The released LiCl not only passivates point defects in TiO2 by forming Li-O-Ti bonds, optimizing the energy level at the TiO2/perovskite interface, but also incorporates into the CsPbI3 lattice, improving its crystallinity. As a result, solar cells based on LiCl@PPy NCPs-TiO2 layer demonstrated a higher PCE of 19.78 %, along with increased open-circuit voltage (VOC) and fill factor (FF) values of 1.161 V and 83.1 %, respectively. Furthermore, the LiCl@PPy NCPs-TiO2 layer also enhanced the stability of CsPbI3 solar cells under humidity conditions.

Achieving the Superior Abrasive Wear Resistance in ZTAP/Fe Composites from the Theoretical Calculations Guided Designing of Metallurgical Interface Transition Layer

Using the first-principles calculations and phonon QHA method, the thermodynamic stability, mechanical and thermophysical properties of binary Ni-Ti phases are obtained. The most thermodynamically feasible binary Ni3Ti phase with a superior elasticity and mechanical tensile strength is designed as the interfacial transition layer between ZTA ceramic particles and iron matrix. A high-Cr white cast iron matrix composite reinforced with ZTA particles is fabricated via infiltration casting process. The microstructures and three-body abrasive wear resistance of the composite are investigated. The obtained ZTAP/Fe composite has a compact metallic Ni3Ti metallurgical transition layer with a small amount of AlNi2Ti and TiO phases in the interfacial region, leading to a strongly adhesion between iron matrix and ZTA ceramic particles due to the presence of covalent Ti-O, Fe-O and Zr-O bonds. The composite exhibits the relative wear resistance 12.9 times higher than that of reference Cr15 specimen. The wear mechanism of the ZTAP/Fe composite is mainly attributed to the removal of iron matrix under the SiO2 abrasives, as revealed from the secondary electron images and laser scanning confocal topography.

Thermally Active Medium-Density Fiberboard (MDF) with the Addition of Phase Change Materials for Furniture and Interior Design.

No matter where we reside, the issue of greenhouse gas emissions impacts us all. Their influence has a disastrous effect on the earth's climate, producing global warming and many other irreversible environmental impacts, even though it is occasionally invisible to the independent eye. Phase change materials (PCMs) can store and release heat when it is abundant during the day (e.g., from solar radiation), for use at night, or on chilly days when buildings need to be heated. As a consequence, buildings use less energy to heat and cool, which lowers greenhouse gas emissions. Consequently, research on thermally active medium-density fiberboard (MDF) with PCMs is presented in this work. MDF is useful for interior design and furniture manufacturing. The boards were created using pine (Pinus sylvestris L.) and spruce (Picea abies L.) fibers, urea-formaldehyde resin, and PCM powder, with a phase transition temperature of 22 °C, a density of 785 kg m-3, a latent heat capacity of 160 kJ kg-1, a volumetric heat capacity of 126 MJ m-3, a specific heat capacity of 2.2 kJ kgK-1, a thermal conductivity of 0.18 W mK-1, and a maximum operating temperature of 200 °C. Before resination, the wood fibers were divided into two outer layers (16%) and an interior layer (68% by weight). Throughout the resination process, the PCM particles were solely integrated into the inner layer fibers. The mats were created by hand. A hydraulic press (AKE, Mariannelund, Sweden) was used to press the boards, and its operating parameters were 180 °C, 20 s/mm of nominal thickness, and 2.5 MPa for the maximum unit pressing pressure. Five variants of MDF with a PCM additive were developed: 0%, 5%, 10%, 30%, and 50%. According to the study, scores at the MOR, MOE, IB, and screw withdrawal resistance (SWR) tests decreased when PCM content was added, for example, MOE from 3176 to 1057 N mm-2, MOR from 41.2 to 11.5 N mm-2, and IB from 0.78 to 0.27 N mm-2. However, the results of the thickness swelling and water absorption tests indicate that the PCM particles do not exhibit a substantial capacity to absorb water, retaining the dimensional stability of the MDF boards. The thickness swelling positively decreased with the PCM content increase from 15.1 to 7.38% after 24 h of soaking. The panel's thermal characteristics improved with the increasing PCM concentration, according to the data. The density profiles of all the variations under consideration had a somewhat U-shaped appearance; however, the version with a 50% PCM content had a flatter form and no obvious layer compaction on the panel surface. Therefore, certain mechanical and physical characteristics of the manufactured panels can be enhanced by a well-chosen PCM addition.

MS23D: A 3D object detection method using multi-scale semantic feature points to construct 3D feature layer

LiDAR point clouds can effectively depict the motion and posture of objects in three-dimensional space. Many studies accomplish the 3D object detection by voxelizing point clouds. However, in autonomous driving scenarios, the sparsity and hollowness of point clouds create some difficulties for voxel-based methods. The sparsity of point clouds makes it challenging to describe the geometric features of objects. The hollowness of point clouds poses difficulties for the aggregation of 3D features. We propose a two-stage 3D object detection framework, called MS23D. (1) We propose a method using voxel feature points from multi-branch to construct the 3D feature layer. Using voxel feature points from different branches, we construct a relatively compact 3D feature layer with rich semantic features. Additionally, we propose a distance-weighted sampling method, reducing the loss of foreground points caused by downsampling and allowing the 3D feature layer to retain more foreground points. (2) In response to the hollowness of point clouds, we predict the offsets between deep-level feature points and the object’s centroid, making them as close as possible to the object’s centroid. This enables the aggregation of these feature points with abundant semantic features. For feature points from shallow-level, we retain them on the object’s surface to describe the geometric features of the object. To validate our approach, we evaluated its effectiveness on both the KITTI and ONCE datasets.

Impact of Graphene Oxide on SERS Enhancement of Arylated Gold Nanospheres: Mechanistic Insight.

The performance of gold nanospheres as substrates for surface-enhanced Raman spectroscopy (SERS) investigation has been compromised by their low adsorption efficiency, high colloidal dispersibility, and diminishing hot spots. However, gold nanosphere substrates modified using aryldiazonium gold(III) chemistry via durable gold-carbon bonds are promising for SERS enhancement due to their controlled organic layer density. In this study, arylated gold nanospheres AuNSs-COOH have shown SERS enhancement when incorporated into graphene oxide (GO) to form nanocomposites (NCs) labeled AuNSs-COOH/GO (AuNCs). Our investigation using X-ray photoelectron spectroscopy (XPS) surface analysis showed that the gold-aryl nanospheres reached their maximum SERS enhancement with an optimal coating. The evaluation included the Au 4f chemical environment and compact graphitic layers for the SERS substrate optimization. The fabricated AuNC substrates demonstrated superior efficiency and reproducibility. A broad linear range of 10-3-10-7 M 4-nitrophenol detection was obtained with exceptional repeatability, as evidenced by the relative standard deviation (RSD) of 9.32%. A detailed investigation of the energy profiles, particularly the valence band maximum (VBM) and band gap values of the substrate and analyte, depicted the electromagnetic (EM) and charge-transfer-induced enhancement and the role of GO inclusion in substrate efficiency in SERS enhancement mechanisms. The finite-difference time domain (FDTD) simulation results revealed that AuNCs incorporated with graphitic nanostructures exhibited the most substantial SERS effect through an EM field enhancement mechanism. This study demonstrated significant SERS enhancement using gold-aryl nanospheres when modified with GO, in contrast to the typical reliance on anisotropic nanostructures.

Synergistic Regulation of Hydrogen Bonds and Electrocrystallization for Enhanced Aqueous Zinc Batteries

AbstractAqueous zinc ion batteries are promising candidates for large scale energy‐storage due to their combination of inherent security and abundant reserves. The Zn metal undergoes continuous plating and stripping during electrochemical cycling, accompanied by parasitic side reactions and dendrite growth, which severely impedes the commercialization of batteries. Here, an innovative strategy is introduced in electrolyte engineering, dedicated to enhancing the stability at the Zn/electrolyte interface. Theoretical calculations and in situ experimental analyses collectively demonstrate that methyl sulfonyl methane (MSM) additives are beneficial in jointly modulating the hydrogen bonding network and the Zn2+ solvation structure, which in turn restricts H2O activity at the interface. Concurrently, the preferential adsorption of MSM on the Zn surface facilitates the controlled growth of compact zinc layers while suppressing dendritic and parasitic reactions. By modulating the electrolyte and managing the electrode interface, the Zn||Zn symmetric battery can be reversibly cycled over 150 days at a current density of 2 mA cm−2, and the assembled Zn||Cu half‐batteries show impressive cycling stability over 3100 cycles. This study provides an in‐depth comprehension of the Zn2+ plating/stripping behavior, and the development of sophisticated electrolyte systems offers practical guidance for constructing high‐performance zinc‐based batteries.

Vertical Variability of Aerosol Pollution in St. Petersburg According to Long-term Lidar Observations

Processing of data obtained using lidar technologies was carried out to identify the vertical variability of the distribution of aerosols in the atmospheric column by month. The results of 227 lidar measurements from 2014 to 2023 were processed in total. It has been established that the concentration and height of compacted aerosol layers begin to increase in spring time, reaches a maximum in July, and from October there is a visible decline in aerosol concentrations in the atmospheric air. It has been established that in the warm season the height of compacted aerosol layers reaches 1200–1800 m, while in the cold season it reaches only heights of 600–1100 m. It was concluded that fine aerosol predominates over the city, based on the calculated Angstrom parameter in the range from 1.95 to 2.91.

Corrosion Behavior of FeCoNiCrAl High-Entropy Alloy in Molten NaNO3-KNO3

Molten nitrates are the main heat transfer fluid (HTF) for concentrated solar power (CSP) systems. However, due to the instability of molten nitrates at high temperatures, the corrosiveness of the molten nitrates poses high requirements for the structural material used in CSP. Therefore, it is urgent to develop highly corrosion-resistant materials. In this study, the corrosion behavior of FeCoNiCrAl high entropy alloys (HEA) in molten NaNO3-KNO3 (60 wt% to 40 wt%) under argon at 600°C is investigated by mass loss and electrochemical methods. The results show that the FeCoNiCrAl HEA experienced severe mass loss during the 100 h immersion due to the high oxygen partial pressure and the galvanic corrosion effect. The corrosion products of FeCoNiCrAl HEA in the melt consist of Fe2O3, Cr2O3, FeCr2O4, and NaFeO2. After immersion for 100 h, an outer layer dominated by porous iron oxides and an inner more compact Cr-rich layer are formed. Furthermore, both of the oxide layers are gradually thickened with the extension of the corrosion time, and the process is manifested by the increased value of the oxide layer resistance Rox and charge transfer resistance Rt in the electrochemical impedance spectra. At the same time, compared with the Rt of 316L stainless steel, it can be seen that with the extension of corrosion time, the Rt of FeCoNiCrAl HEA is larger and shows better corrosion resistance in the same corrosive environment. In addition, FeCoNiCrAl HEA shows a higher corrosion potential and a lower corrosion current density than 316L in molten nitrates at 600°C.

Mechanism for corrosion protection of β-TCP reinforced ZK60 via laser rapid solidification

It remains the primary issue to enhance the corrosion resistance of Mg alloys for their clinical applications. In this study, β-tricalcium phosphate (β-TCP) was composited with Mg-6Zn-1Zr (ZK60) using laser rapid solidification to improve the degradation behavior. Results revealed rapid solidification effectively restrained the aggregation of β-TCP, which thus homogenously distributed along grain boundaries of α-Mg. Significantly, the uniformly distributed β-TCP in the matrix promoted the formation of apatite layer on the surface, which contributed to the formation of a compact corrosion product layer, hence retarding the further degradation. Furthermore, ZK60/8β-TCP (wt. %) composite showed improved mechanical strength, as well as improved cytocompatibility. It was suggested that laser rapidly solidified ZK60/8β-TCP composite might be a potential materials for tissue engineering.

Super-Nernstian potentiometric response of InN/InGaN quantum dots by fractional electron transfer

The potentiometric response of InN/InGaN quantum dots (QDs) on Si (111) is experimentally studied and modeled as a function of the In content and morphology of the InGaN layer below the QDs due to the changing N flux in stationary plasma-assisted molecular beam epitaxy. For isolated core–shell InGaN nanowires formed for N-rich growth, sub-Nernstian response with Cl− anions as the test analyte is observed. For compact columnar InGaN layers formed in a very narrow range of N flux at the N-rich to metal-rich growth transition, a maximum super-Nernstian response of 100 mV/decade is achieved, provided the In content is high. With reducing N flux and In content, low super-Nernstian response and finally sub-Nernstian response are re-established for compact planar GaN layers. The maximum super-Nernstian response and the transition to sub-Nernstian response are quantitatively modeled by the quantum partition of electrons inside and outside of the QDs and consequent fractional electron transfer in the artificial chemical reaction of the QDs with the anions.

Research of the properties of the sandwich-structured Ni60CuMo self-lubricating coating with stepped hardness distribution on Vermicular cast iron by laser cladding

To enhance the wear resistance of Vermicular cast iron (RuT300) and achieve the stepped hardness distribution for the impact deformation resistance in the middle and lower part of the coating and wear resistance in the surface of the coating, the sandwich-structured Ni60CuMo coating with the transition layer was fabricated on RuT300 by laser cladding. The microstructure, hardness, and fracture toughness for the coating were analyzed, and the effect of different loads on wear resistance was investigated. The wear-resistant layer mainly contains Ni-based solid solution, hard phase of chromium compound and some ductile Cu phases. The hardness for coating without cracks shows the stepped distribution, increasing to 381HV0.5, 419HV0.5, and 490HV0.5 in the wear layer, transition layer, and heat-affected zone, respectively. The transition layer can suppress the impact of carbon from the substrate on the hardness of the wear-resistant layer. The wear resistance of the coating demonstrates a self-adaptive enhancement effect with increasing load. As the load increases from 10 N to 30 N and 50 N, the wear rate decreases from 2.865 to 1.525 and 1 (×10⁻⁴mm³N⁻¹m⁻¹). The main wear mechanism is oxidative wear. The extruded ductile Cu phase causes the wear debris to adhere it and the compacted oxide glaze layer is formed with the high load, then the compacted oxide glaze layer isolates oxygen and reduces oxidative wear. In contrast, incomplete oxide layers at low load fail to provide effective isolation, and cracks on the subsurface serve as critical pathways for continued oxygen penetration, resulting in more severe oxidative wear.

A HKUST-1 coating with copper metal active site enables stabilized zinc metal anode

Aqueous zinc-ion batteries (AZIBs) are considered to be one of the alternatives for large-scale energy storage devices due to unique advantages. However, the harmful Zn dendrites generation of Zn anodes seriously hinders the development of AZIBs. Herein, Cu3(BTC)2 (HKUST-1) as a compact functional interface layer on the surface of bare Zn foil is shown to improve the reversibility of Zn-plating/stripping process. Interestingly, HKUST-1 possesses high porosity, large number of water molecule vacancies, and Cu active center, which help to enhance the diffusion kinetics of Zn2+ and reduce the surface free energy of Zn electrode. Combining theoretical calculations with experiments, the HKUST-1 can contribute to the desolvation process of Zn[(H2O)6]2+ and balance Zn2+ concentration, which thus accelerate Zn2+ transfer kinetics, lower interfacial energy, and homogenize ion-distribution. Attributed to these superiorities, the HKUST-1@Zn symmetric cells demonstrate excellent stable plating/stripping for over 250 h under ultra-high current density (20 mA/cm2 and 20 mAh/cm2). Furthermore, a HKUST-1@Zn||MnO2 full cell exhibits an enhanced long-cycling performance with a discharge capacity of 114 mAh/g after undergoing 500 cycles. All results demonstrate the potential application of HKUST-1 coating in AZIBs.

Experimental and numerical investigation of the solid cold-welding properties of the APB process of Al/Cu bulk composites

AbstractNowadays, the use of bimetallic laminates with special capabilities is increasing and has experienced high growth. These properties include high mechanical properties, corrosion resistance, lightweight, and thermal stability. Among the technologies of multilayer composite materials, Accumulative Press Bonding (APB) as a solid-phased method of welding is one of the most common techniques for the production of multilayer composites. One of the most important aims for this choice is the press pressure, which can create a strong and suitable mechanical connection between produced metal layer components. In this study, the APB method has been used to produce bimetal aluminum/copper bulk composites as its novelty for the first time. After that, the effect of pressing parameters such as strain and number of layers on the stress distribution has been investigated. The shear stress among the layers reached 4 MPa for the samples with eight layers which is a good condition to generate a successful bonding. With increasing the thickness reduction ratio, the stress applied to the layers has also increased. As the thickness decreases, the interlayer shear stresses also increase which leads to a better bonding between layers. With increasing the thickness reduction ratio, the amount of layers sinking in each other was greater than before, which led to the crushing of copper layers along the entire length of the sample. During the process, as the number of passes increased, the volume of virgin material in the direction of the press rose, which led to increased compaction and better adhesion of Al and Cu layers to each other. The bonding strength enhances from 47 to 95 N for samples manufactured with one and four cycles of APB due to the increment of virgin metal normal to the pressing direction showing a 102% enhancement.