Resistive Layer Research Articles

Preparation and properties of Ag-containing porous layer on 6061 aluminum alloy surfaces

This study focused on the preparation of Ag-containing porous layers on the surface of a 6061 aluminum alloy using different voltages. The microstructure, Ag deposition form, corrosion resistance, and antibacterial properties of the Ag-containing porous layers on the 6061 aluminum alloy were analyzed using scanning electron microscopy, X-ray photoelectron spectroscopy, electrochemical workstation, and antibacterial tests. The results indicated that the Ag-containing porous layer prepared at 30 V exhibited the highest Ag deposition and antibacterial rate, amounting to 1.78 wt% and 99.73 %, respectively. The deposited Ag mainly existed in the form of Ag+ combined with O2− and SO42− within the Ag-containing porous layers. Compared to that of the 6061 aluminum alloy matrix, the Ag-containing porous layer prepared at 30 V had a wear volume of 0.015 mm3, a reduction of 98.37 %, an increase in the corrosion potential (Ecorr) to −0.485 V, and an increase of 0.848 V. In conclusion, Ag-containing porous layers demonstrated significant antibacterial, wear resistance, and corrosion resistance properties.

Evaluating the efficacy of newly synthesized amino acid derivatives as corrosion inhibitors in acidic solutions

Three benzimidazole derivatives, with tryptophan (BIT), tyrosine (BIY), and histidine (BIH) amino acid units, have remarkable protective properties as eco-friendly corrosion inhibitors for steel under severe acidic conditions. At a temperature of 303 K, the corrosion inhibition efficiency of BIT, BIY, and BIH at a concentration of 10 mM is 90.09 %, 92.53 %, and 93.43 %, respectively. Electrochemical tests indicate that the adsorption of these substances on the substrate leads to an increase in charge transfer resistance and interfacial electric double layer thickness. This effectively hinders the dissolution of metal and the evolution of hydrogen. The analysis of the surface structure and appearance using SEM-EDS indicates that the inhibitors have the ability to create a protective coating through both chemical and physical bonding, effectively protecting the metal from corrosive substances. Theoretical calculations, such as Density Functional Theory (DFT) and Natural Bond Orbital (NBO) analysis, along with FUKUI analysis, help identify active sites and adsorption configuration. This enhances our understanding of the corrosion mitigation mechanism. These findings align with the experimental conclusion that the formation of a stable protective film contributes to superior inhibition performance against acidic corrosion conditions.

Steam Condensation Heat Transfer in the Presence of Noncondensable Gases (NCGs) in Nuclear Power Plants (NPPs): A Comprehensive Review of Fundamentals, Current Status, and Prospects for Future Research

Efficient steam condensation is crucial for safe nuclear power plant (NPP) operations, preventing pressure buildup, overheating, and the release of radioactive materials. However, the presence of noncondensable gases (NCGs), such as air, nitrogen, hydrogen, or helium, can hinder the condensation process by creating a thermal resistance layer that impedes steam diffusion and condensation on the system’s surface. Maximizing the efficiency of steam condensation requires a thorough grasp of the fundamental processes, theories, advancements, and technical hurdles. Therefore, this work thoroughly addresses these needs, with a particular emphasis on addressing the challenges posed by NCGs by dividing the work into four thematic areas. The first theme relates to a comprehensive examination of pure steam condensation phenomena, which includes an exploration of familiar condensation scenarios and various film condensation types. The second theme examines condensation in the presence of NCGs, their mixture properties, and related theories and modelling of heat and mass transfer. The third theme investigates condensation in NPP by exploring passive cooling systems and condensation phenomena under both natural and forced convection conditions during nuclear accidents, the origin of NCGs in NPP and their transportation aspects. This is followed by experimental work related to condensation scenarios and scale. Finally, the last theme looks upon the recent advancements in computational fluid dynamics (CFD) modelling of wall condensation, system analysis codes coupling with CFD, and the implementation of machine learning (ML) for predicting the condensation HTC. By bridging the gap between fundamental knowledge and practical applications, the four thematic areas presented in this work are aimed at providing a comprehensive foundation for researchers and experts in the field of steam condensation when NCGs are involved. The ultimate objective is to bolster the safety and efficacy of NPP operations by understanding the heat and mass transfer mechanisms while mitigating the risk of catastrophic events.

Heat Resistance of Surface Layers Obtained by Electron Beam Surfacing with Cr–B Powder Mixtures

Heat Resistance of Surface Layers Obtained by Electron Beam Surfacing with Cr–B Powder Mixtures

Assessment of Axial Resistance of Piles Considering Consolidation Setup and Aging Setup Using Direct Pile Cone Penetration Test Methods

This paper focuses on evaluating the increase in axial pile resistance subjected to both consolidation and aging setups. Consolidation and aging setup models were first developed to estimate the setup parameters based on databases collected from literature, which include 10 instrumented piles for consolidation setup and 26 test piles for long-term aging. The eight top-performing pile cone penetration test (CPT) methods that were evaluated in a previous study were used to estimate the side resistance of soil layers at 14 days after pile driving. The developed consolidation and aging setup models were then used to extrapolate the results to evaluate the side resistance of each soil layer at the end of consolidation and for long-term aging. The estimated side and total resistances were compared with the measurements from pile load tests considering both consolidation and aging setups. The resistances estimated before and after completion of excess pore water pressure dissipation indicates that significant aging takes place after consolidation setup. The value of consolidation setup parameter ( Ac) was 0.53, and, for aging, the setup parameter ( Ag) was 0.23 in clay and 0.16 in sand. The results show that all pile CPT methods with/without using a consolidation setup model tend to underestimate the unit side resistance of clay soil layers. The use of pile CPT methods in combination with an aging model improved the accuracy of pile CPT methods, and this was verified using load test results for five piles subjected to aging. The Philipponnat and University of Florida (UF) methods showed the best performance on estimating the total resistance of piles subjected to aging.

Controlled in-situ reduction strategy for synthesis of transparent conductive metal meshes using tannic acid-based photoresists

Transparent conductive films (TCFs) that converge high transmittance and high conductive properties are essential for many optoelectronic devices, and efforts have been made to acquire films with high transmittance as well as low resistance of the thin layer by low-cost means. Here, we introduce a novel and simple strategy for the controlled in-situ templated synthesis of a transparent conductive metal mesh by utilizing the good reducibility to silver ions of the patterned tannic acid (TA)-based photoresists. To achieve this, mesh patterns with tunable line width were first printed using the TA-based negative photoresists by laser direct writing equipment. Within the patterned domains, the phenolic hydroxyl groups could interact with metal ions and act as reducing agents, thus accelerating the in-situ growth of silver nanoparticles to fabricate silver grids. By changing the line width of the designed patterns and the PH of the plating solution, the metal grids with a high transmission (T) of 91.5% and a thin-layer resistance (Rs) as low as 4.15 Ω sq.−1 are ultimately achieved after annealing treatment. Our description demonstrates a simple and effective approach that is potentially scalable to other materials as well.

The effect of AlCrN, TiN and Ni-Cr-Nb coatings on the wear and corrosion performance of 45 # steel in 3.5 % sodium chloride solution

The press bar of the oil press is prone to corrosion and abrasion in the high-temperature and high-pressure environment, which reduces the quality of oil and the efficiency of agricultural production. In this paper, Ni-Cr-Nb, TiN and AlCrN coatings were prepared on the surface of press bar substrate by thermal spraying and multi-arc ion plating technology. The tests were analyzed by modern analytical methods such as HV-1000Z micro Vickers hardness tester, SEM, XRD and electrochemical corrosion. The results show that: Vickers hardness tester analysis shows that the surface hardness of AlCrN coating is 3.6 times higher than that of the base material, which is higher than that of several other coatings; SEM shows that the surfaces of the Ni-Cr-Nb, TiN and AlCrN coatings are smooth and even, the film structure is compact and uniform, and the thickness of the coating film is 5.67μm, 6.31 μm and 6.55 μm, respectively; XRD shows the elemental content of each coating, and the Al atoms in the AlCrN coating have good corrosion resistance; Electrochemical corrosion experiment shows that AlCrN coating has the biggest and most important advantages. It shows that AlCrN coating has the maximum potential and minimum corrosion current density, which indicates that its corrosion resistance is the best, followed by TiN coating, Ni-Cr-Nb layer of the corrosion resistance of the first two coatings, but better than the press bar substrate.

Spatiotemporal dynamics of ecological security pattern based on an optimized assessment framework and circuit theory: a case of Fuzhou City, China

The construction of the ecological security pattern (ESP) and ensuring its integrity are the focal points of ecological actions. However, existing evaluation frameworks lack comprehensiveness, and studies addressing temporal dimensions are limited. This study constructed a comprehensive framework to evaluate ESP and introduced a method to portray the relationship between ecological security status and landscape structure. Initially, multiple indicators were optimized to construct an ecological security index (ESI). The relationship between ESI and landscape structure was quantified. Then, fifteen spatiotemporal factors were combined using the Analytical Hierarchy Process to construct an ecological resistance layer. Finally, Circuit theory was applied to visualize trends in ESP. The findings indicated that ecological security was generally better but with a downward trend. The relationship between ESI and landscape fragmentation was mainly a tradeoff. The area of stable ecological sources was 1251.06 km2 (1996–2021). The number of minimal-cost corridors decreased continuously. Ecological sources with the highest conservation priority were the largest (1336.2 km2) in 2021. The number of pinch points was 25, 31, and 30, while ecological barriers covered 51.5, 148.74, and 139.51 km2 in 1996, 2008, and 2021, respectively. This study will serve as a valuable methodological reference and support ecological civilization projects in Fuzhou.

Study of ablation phase in double-wire Z-pinch based on optical Thomson scattering

Measurement of plasma parameters during the ablation phase in the Z-pinch is crucial for investigating the dynamic behaviors. In this study, optical Thomson scattering was employed to measure the temperature and velocity of the ablation plasma in a double-wire Z-pinch. The scattering spectra profiles were fitted using a model that considered the velocity distribution. The experimental results revealed the energy evolution of ablation plasma, the establishment of the global magnetic field and the development of axial non-uniformities. The precursor plasma was found to play a key role in strengthening the global magnetic field. A resistive layer near the wire core with a size of 1.5 mm was observed in the ablation plasma after the precursor plasma column formed. The plasma underwent rapid heating in this layer, the electron temperature rises from 17 eV to 22 eV. Upon leaving this layer, electron the temperature is stable at around 22 eV. The radial distribution of the ablation rate increases and decreases, indicating the axial motion of the ablation plasma, which could be caused by the tilt motion of the stream and the secondary modulation of the natural wavelength.

Comprehensive Unveiling of the Oxidation Resistance and Corrosion Protection of an Oxide Layer Formed on the Gd-Alloyed AZ80 Alloy Surface

Comprehensive Unveiling of the Oxidation Resistance and Corrosion Protection of an Oxide Layer Formed on the Gd-Alloyed AZ80 Alloy Surface

Impedimetric sensor based on molecularly imprinted polythionine from deep eutectic solvent for epinephrine determination

Deep eutectic solvents have obtained growing interest in analytical chemistry due to opportunities related the green chemistry paradigm, i.e., substitution of organic solvents, application of nontoxic ingredients and minimal quantities of wastes formed in their synthesis and usage. In this work, the advantages of deep eutectic solvents were shown in the development of electrochemical sensor for epinephrine determination. Polythionine molecularly imprinted with epinephrine (PTNMIP) was electrodeposited from natural deep eutectic solvent (NADES) consisted of citric acid, glucose, and water in 1:1:6 molar ratio and tested with standard solutions of epinephrine, pharmaceutical preparations, and artificial samples of biological liquids. Only one drop (100 µL) of the monomer dissolved in NADES was applied for sensor preparation on the platform of screen-printed carbon electrode. Electropolymerization was performed by multiple scanning of the potential. The formation of molecular imprints was confirmed by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). After the template removal, the charge transfer resistance of the surface layer depended on the epinephrine concentration in the range from 100 nM to 316 µM (limit of detection 50 nM). Selectivity of the signal was confirmed against serotonin and norepinephrine commonly present in biological liquids. Sensor was successfully tested for the determination of epinephrine in spiked solutions mimicking influence of the plasma electrolytes, serum proteins, and in real saliva samples. The recoveries calculated for 10 μM epinephrine ranged from 98.3 to 102.6%. Insignificant influence of the additives and stabilizers present in medications was eliminated by sample dilution. Impedimetric sensor developed showed good opportunities for further application in clinical diagnostics, pharmacokinetics studies and medication manufacture control.

Optimization of Bilayer Resistive Random Access Memory Based on Ti/HfO2/ZrO2/Pt.

In this paper, the electrothermal coupling model of metal oxide resistive random access memory (RRAM) is analyzed by using a 2D axisymmetrical structure in COMSOL Multiphysics simulation software. The RRAM structure is a Ti/HfO2/ZrO2/Pt bilayer structure, and the SET and RESET processes of Ti/HfO2/ZrO2/Pt are verified and analyzed. It is found that the width and thickness of CF1 (the conductive filament of the HfO2 layer), CF2 (the conductive filament of the ZrO2 layer), and resistive dielectric layers affect the electrical performance of the device. Under the condition of the width ratio of conductive filament to transition layer (6:14) and the thickness ratio of HfO2 to ZrO2 (7.5:7.5), Ti/HfO2/ZrO2/Pt has stable high and low resistance states. On this basis, the comparison of three commonly used RRAM metal top electrode materials (Ti, Pt, and Al) shows that the resistance switching ratio of the Ti electrode is the highest at about 11.67. Finally, combining the optimal conductive filament size and the optimal top electrode material, the I-V hysteresis loop was obtained, and the switching ratio Roff/Ron = 10.46 was calculated. Therefore, in this paper, a perfect RRAM model is established, the resistance mechanism is explained and analyzed, and the optimal geometrical size and electrode material for the hysteresis characteristics of the Ti/HfO2/ZrO2/Pt structure are found.

A computational model of an air-layer radiant cooling panel for optimizing and design

Radiant cooling systems have become a research hotspot in recent years. The air-layer radiant cooling panel always had good performance, but there is relatively little research on it. This paper aims to optimize an air-layer radiant cooling panel by establishing a computational model and analyzing its accuracy through experiments. Through the computational model, the effects of surface emissivity, the thickness of the air layer and high thermal resistance material, pipe spacing on the heat transfer performance of the air-layer radiating cooling panel, and the corresponding optimizations have been studied in this paper. Based on the results, it is recommended that a pipe spacing of between 0.1 m and 0.25 m can achieve higher cooling capacity and lower initial costs. The thinner the thickness of the air layer and decorative layer, the better the heat transfer performance. High emissivity materials need to be used on the surface of the air-layer radiant cooling panel to enhance radiant heat transfer. In the process of analyzing the spacing between pipes, a method for calculating the large temperature difference of the fluid has been added, which can help us estimate the cooling capacity in practical engineering, balance initial costs and cooling capacity, and better meet cooling needs.

Highly radiation-stable DLC coatings for a new class of detectors: Structural and morphological features

Within the framework of the FTM-NEXT INFN (Fast Time Micropattern gaseous detectors - next of Nuclear Physics National Institute) experiment, we produced hydrogen-free diamond-like carbon films through pulsed-laser deposition to serve as resistive layers in modern resistive micro-pattern gaseous detectors that must work in extreme radiation environments at future colliders. To obtain homogeneous diamond-like carbon coatings, over medium-to-large size (3 cm × 3 cm), with excellent adhesion to the substrate and with typical surface resistivity values in the range of 1–100 MOhm/sq, growth conditions had to be optimized. In this paper we report on the stability of resistive diamond-like carbon layers subjected to increasing doses of irradiation with proton beams accelerated to an energy of 2 MeV. The morphological, structural, and electrical properties, also at the nanoscale level, of diamond-like carbon coatings following ion irradiation were studied by electron microscopy, electron diffraction, electrical transport characterization and scanning tunneling spectroscopy.

Atomic layer annealing for spatial tailoring in sub-4 nm AlN RRAM devices with low-voltage operation

This article investigates the spatial tailoring of nitrogen vacancies by atomic layer annealing (ALA) on resistive random access memory (RRAM) devices with an AlN resistive switching layer. The ALA technique involves the in-situ layer-by-layer He/Ar plasma treatment in the cycle of atomic layer deposition for AlN. The AlN RRAM devices prepared with the ALA treatment near the TiN electrode have significantly superior uniformity of the operation voltages and the switching resistances, along with a lower cycle-to-cycle variation in endurance. This enhancement could be attributed to the relatively stable location of rupture and formation of conductive filaments, as a result of the film densification and the suppression of nitrogen vacancies in the AlN region treated with the ALA process. The AlN RRAM devices also demonstrate excellent retention of more than 106 seconds at 125°C. In addition, the ultra-thin 3.3 nm AlN switching layer contributes to low operation voltages of AlN RRAM. The outcomes manifest that the ALA technique could effectively improve the properties of nanoscale materials through precise spatial tailoring, with an accuracy up to atomic scale.

Effect of LLZTO Tablet Pressing Process on Electrochemical Properties of Button Batteries

AbstractThe garnet‐type Li6.4La3Zr1.4Ta0.6O12 (LLZTO) is a widely studied solid‐state electrolytes (SSEs) due to its high ionic conductivity and electrochemical stability. However, the conventional preparation process of LLZTO electrolyte tablets has encountered several issues such as powder embedment in the mold gaps and inadequate bonding between powders, leading to fragile electrolyte tablets that are prone to cracking. In this study, the effects of LLZTO electrolyte tablet pressing process parameters, including mixed powder content, polyvinyl alcohol (PVA) content and cold pressing pressure, on the electrochemical properties of button cells were investigated. The results indicated that the produced solid‐state electrolyte tablets with high quality, low interfacial resistance and low surface passivation layer (Li2CO3) content was obtained by using 0.8 g of mixed powder content, 0.7 g of PVA content and 20Mpa pressure. The interface resistance decreased from 2927.1 Ω to 1069.7 Ω under these conditions. Additionally, the Li symmetric cell treated with adhesive exhibited stable cycling for over 400 hours at 25 °C under a current density of 0.1 mA ⋅ cm−2.

Effect of pool temperature on microstructure and corrosion resistance of PTAW Ni layer

In plasma transferred arc welding (PTAW), the weld pool temperature often fluctuates. The spray weld layer is prone to overheating, leading to adverse effect on its performance. This study investigated the influence of spray welding current on the weld pool temperature and in turn on the microstructure, microhardness and corrosion resistance of the PTAW-Ni layer on a steel substrate. Weld pool temperature increased with increasing spray welding current and varied along the welding gun path before reaching the steady state. With increasing pool temperature, more Fe diffused from the substrate into the spray weld layer, leading to a widened fusion zone, an increased dilution rate and a decreased microhardness. The spray weld layer has a dendritic microstructure. The dendrites have a higher Cr content, while the interdendritic regions have a higher Ni content. Increasing weld pool temperature increased diffusion, resulting in reduced enrichment of the Cr and Ni elements. The increase of Fe and decrease of Cr in the spray weld layer caused the decreasing corrosion resistance.

Characteristics and hot corrosion behavior of NiCrAlY metal bonding layers prepared by different processes

The hot corrosion experiments of René N5 alloy coated with three different NiCrAlY metal bonding layers are carried out, that the layers are prepared by different methods (APS, HVAF and MIP). Compared with bare René N5 alloy samples, the hot corrosion resistance of coated samples is improved. It can be attributed to the small internal stress of the surface oxide layer on the coating sample, which is difficult to spall, reducing the degree of hot corrosion reaction. The hot corrosion resistance of NiCrAlY layers is MIP > HVAF > APS, which is positively positively related to the density of layers, because the influence of element diffusion in the process of hot corrosion is effectively slowed down.

Macroscopic Characteristic and Properties of Inconel 625 Cladding Layers on a Cylinder Liner Based on Laser Cladding Assisted by a Steady-State Magnetic Field

Cylinder liners, which are an vital part of marine diesel engines, are prone to damage owing to the pool working conditions of reciprocating friction and electrochemical corrosion. As a burgeoning manufacturing technology, laser cladding has a prospective application on repairing and performance enhancement of cylinder liners. The performance of cladding layers on cylinder liners reported by current studies is not satisfactory. The laser cladding, assisted by the steady state magnetic field on the cylinder liner, is an effectual method to cover the shortage. However, there are few studies about that. In this study, single-track Inconel 625 cladding layers were carried out on a cylinder liner, assisted by a steady-state magnetic field. The effects of the magnetic field intensity and direction on the geometrical characteristics (width, height, penetration, and dilution ratio), microstructure, phase composition, microhardness, wear resistance, and corrosion resistance were investigated. According to the results obtained, adding a magnetic field with a small magnetic field intensity can significantly enhance the flatness, hardness, friction, wear resistance, and corrosion resistance of the cladding layer. Applying a magnetic field in the horizontal direction was conducive to improving the corrosion resistance of the sample. With the application of a vertical magnetic field, the microhardness increased, and wear resistance, as well as the flatness of the cladding layer, were improved.

Characterisation of mode-I fracture resistance of adhesive layers with imperfections

In this work, a novel procedure to evaluate the influence of imperfections at the interface (such as voids and interfacial failure) on the fracture resistance of adhesive joints in mode-I debonding is proposed, based on an image-processing analysis of the crack surface. Its application to the characterisation of fracture resistance of aluminium DCB specimens bonded with an epoxy adhesive leads to a more accurate evaluation of the ‘effective’ fracture resistance by taking into account the distribution of imperfections along the interface, therefore also confirming that the typical oscillations and drops in the load–displacement curve can be attributed to the imperfections.