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This study explored the fascinating field of high-performance nanoscale metallic multilayer composites, focusing on their magnetic, optical, and radiation tolerance properties, as well as their thermal and electrical properties. In general, nanoscale metallic multilayer composites have a wide range of outstanding properties, which differ greatly from those observed in monolithic films. Their exceptional properties are primarily due to the large number of interfaces and nanoscale layer thicknesses. Through a comprehensive review of existing literature and experimental data, this paper highlights the remarkable performance enhancements achieved by the precise control of layer thicknesses and interfaces in these composites. Furthermore, it will discuss the underlying mechanisms responsible for their exceptional properties and provide insights into future research directions in this rapidly evolving field. Many studies have investigated these materials, focusing on their magnetic, mechanical, optical, or radiation-tolerance properties. This paper summarizes the findings in each area, including a description of the general attributes, the adopted synthesis methods, and the most common characterization techniques used. The paper also covers related experimental data, as well as existing and promising applications. The paper also covers other phenomena of interest, such as thermal stability studies, self-propagating reactions, and the progression from nanomultilayers to amorphous and/or crystalline alloys. Finally, the paper discusses challenges and future perspectives relating to nanomaterials. Overall, this paper is a valuable resource for researchers and engineers interested in harnessing the full potential of nanoscale metallic multilayer composites for advanced technological applications. [ABSTRACT FROM AUTHOR]

Electro-conductive fabrics are key materials for designing and developing wearable smart textiles. The properties of textile materials depend on the production method, the technique which leads to high conductivity, and the structure. The aim of the research work was to determine the factors affecting the electrical conductivity of woven fabrics and elucidate the mechanism of electric current conduction through this complex, aperiodic textile material. The chemical composition of the material surface was identified using scanning electron microscopy energy dispersion X-ray spectroscopy. The van der Pauw method was employed for multidirectional resistance measurements. The coefficient was determined for the assessment of the electrical anisotropy of woven fabrics. X-ray micro-computed tomography was used for 3D woven structure geometry analysis. The anisotropy coefficient enabled the classification of electro-conductive fabrics in terms of isotropic or anisotropic materials. It was found that the increase in weft density results in an increase in sample anisotropy. The rise in thread width can lead to smaller electrical in-plane anisotropy. The threads are unevenly distributed in woven fabric, and their widths are not constant, which is reflected in the anisotropy coefficient values depending on the electrode arrangement. The smaller the fabric area covered by four electrodes, the fewer factors leading to structure aperiodicity. [ABSTRACT FROM AUTHOR]

In recent years, there is a growing demand for materials that can both improve the mechanical properties of structures and carry out health monitoring and risk warning. In this case, in order to realize distributed deformation monitoring, a new method of making geogrid by 3D printing technology is proposed. The grille rib is made by embedding the conductive polymer (ground carbon fiber as conductive filler) into the insulating shell (PLA material) in the specified path, and then the rib is vertically crossed into each other to form a grille sample. In order to study the distributed deformation monitoring function of this grid, a manual push–pull testing machine was used to conduct a load–unload experiment to analyze the change rule of resistance on the grid plane. The following conclusions were obtained: the closer the ribs are to the load bearing point, the greater the change in resistance, and conversely, the farther the ribs are from the load bearing point, the smaller the change in resistance. Depending on the geogrid network characteristics, the electrical resistance distribution on the geogrid plane can be obtained by superimposing the resistance values of the horizontal and longitudinal ribs, then the location and the magnitude of deformation can be estimated. Additionally, this study carried out numerical simulation of the grid model based on ANSYS 15.0 software and compared with the loading experiment results to verify that the force deformation position can be retrieved through the change of resistance. [ABSTRACT FROM AUTHOR]

Al-doped ZnO combines high transparency and conductivity with abundant and non-toxic elements; making it suitable for optoelectronic devices with large-scale applications. In order to check the quality of the material deposited over large areas, spectroscopic ellipsometry is a powerful technique that allows the determination of various optical and electrical parameters by applying suitable oscillator models. This technique is used here to obtain sheet resistance and visible transmittance data at several equidistant points of Al:ZnO thin films deposited using DC sputtering on 15 cm × 15 cm glass substrates. Independent measurements using other optical (spectrophotometry) and electrical (four point probe) methods show analogous visible transmittance but somewhat higher resistance values than those obtained with ellipsometry, which is explained by the contribution of grain-boundary scattering compared to in-grain properties provided using ellipsometry. However, the mapping of the data gives a similar spatial distribution to the different types of measurement; therefore, proving the capacity of ellipsometry to study with a single tool the uniformity of the optical and electrical characteristics of large areas. [ABSTRACT FROM AUTHOR]

The grain size of a metallic coating or the surface layer after the machining of metallic parts strongly impacts corrosion and wear properties along with fatigue behavior. By measuring the combined electrical resistance of this layer and the substrate using the four-point probe method, the grain size of the layer can be determined. For different grain shapes, models are derived based on an analytical approach. The parameters in the models can be determined by appropriate calibration measurements. As a result, the grain sizes can be determined quickly with a non-destructive method, which can be applied to ensure consistent coating or machining results as part of quality control routines in industrial processes. [ABSTRACT FROM AUTHOR]

There are two main ways of carrying out the electrical discharge machining of the insulating ceramics: changing the electrical and chemical properties of ceramics due to additives in producing composites/nanocomposites and changing the electrical and chemical properties in the interelectrode gap. This review summarizes and analyzes the current data on the machinability in water suspension and hydrocarbons depending on the electrical properties of the ceramic composites and assisting means such as coating and powder. There are provided the existing approaches and original methods for solving the global problem of the electrical discharge machining of insulating ceramics, suggesting further development of the existing methods since, up to now, the experimental research is non-systemic. The dependencies of the machinability on the electrical properties of conductive ceramic composites, the specific electrical resistance of the assisting coating, and the assisting powder's band gap and concentration for machining insulating ceramics are revealed. The higher the electrical conductivity, the higher the machinability of ceramic composites, and the lower the band gap, the higher the machinability for insulating ceramics. Two technological gaps were revealed in the powder's concentration that can be a particular case of logarithmic decrement of attenuation. The proposed approach suggests using assisting powder with the lower band gap. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) is known to be highly inert, and this makes it difficult to be metallized. In addition, Pt electroless plating is rarely reported in the metallization of polymers. In this study, the metallization of biocompatible Pt metal is realized by supercritical CO2 (sc-CO2)-assisted electroless plating. The catalyst precursor used in the sc-CO2 catalyzation step is an organometallic compound, palladium (II) acetylacetonate (Pd(acac)2). The electrical resistance is evaluated, and a tape adhesion test is utilized to demonstrate intactness of the Pt layer on the PET film. The electrical resistance of the Pt/PET with 60 min of the Pt deposition time remains at a low level of 1.09 Ω after the adhesion test, revealing positive effects of the sc-CO2 catalyzation step. A tensile test is conducted to evaluate the mechanical strength of the Pt/PET. In-situ electrical resistances of the specimen are monitored during the tensile test. The fracture strength is determined from the stress value when the short circuit occurred. The fracture strength is 33.9 MPa for a specimen with 30 min of the Pt deposition time. As the Pt deposition time increases to 45 min and 60 min, the fracture strengths reach 52.3 MPa and 65.9 MPa, respectively. The promoted fracture strength and the decent electrical conductivity demonstrate the advantages toward biomedical devices. [ABSTRACT FROM AUTHOR]

In this study, hard wear-resistant Ti-Si-C coatings were deposited on Cu-Cr materials to improve their performance as sliding electrical contact materials. A ceramic disk composed of Ti3SiC2 and TiC phases was used as a target for DC magnetron sputtering to deposit the coatings. The influence of the power supplied to the magnetron on the chemical composition, structure, and friction coefficient of the coatings was examined. The coatings demonstrated high hardness (23–25 GPa), low wear rate (1–3 × 10−5 mm3/N/m) and electrical resistance (300 μOhm·cm), and fair resistance to electroerosion. The coating deposited at 450 W for 30 min displayed optimal properties for protecting the Cu-Cr alloy from the arc effect. [ABSTRACT FROM AUTHOR]

Tensile tests and fatigue tests on differently heat-treated low carbon (non- and low-alloy) steels were conducted and accompanied by non-destructive electrical resistometric (ER) and magnetic Barkhausen noise (MBN) measuring devices, in order to establish an improved short-time fatigue life estimation method according to StressLife. MaRePLife (Material Response Partitioning) is the hereby proposed method for calculating S–N curves in the HCF regime, based on the partitioning of material responses acquired during the above-mentioned mechanical tests. The rules were set to make use of the information gathered from pre-conducted tensile tests, which helps to determine the parameters of two load increase tests (LIT) and two constant amplitude tests (CAT). The results of the calculated S–N curves were satisfactory and could be verified by more separately conducted fatigue tests on specimens under different material conditions. [ABSTRACT FROM AUTHOR]

Textile production has been steadily increasing for a few decades and, as a result, the amount of industrial textile waste is also increasing. This waste can be reused as raw material to produce new functional composites. Such materials can be used for special purposes with varying combinations of physical and chemical properties by using polymers modified with thin semiconductive or electrically conductive layers of binary inorganic compounds. In this paper, a study of the possibilities of altering the properties of synthetic fiber conductivity by modification with copper selenide is presented. A two-step adsorption/diffusion method was used for the copper selenide layer forming on the surface of the fibers. The treatment process was repeated cyclically. To evaluate the morphological properties of CuxSe treated fibers, scanning electron microscopy (SEM) and energy dispersion X-ray (EDX) were performed. The study showed that the chosen modification method is more suitable for PA and PAN fibers. Dense layers of copper selenides were successfully formed on their surface, which significantly reduced their electrical resistance. [ABSTRACT FROM AUTHOR]

Self-sensing concrete is a smart material known for its cost-effectiveness in structural health-monitoring areas, which converts the external stimuli into a stress/strain sensing parameter. Self-sensing material has excellent mechanical and electrical properties that allow it to act as a multifunctional agent satisfying both the strength and structural health-monitoring parameters. The main objective of this review is to understand the theories and principles behind the self-sensing practices. Many review papers have focused on the different types of materials and practices that rely on self-sensing technology, and only a few articles have discussed the theories involved. Understanding the mechanism and the theories behind the conduction mechanism is necessary. This review paper provides an overview of self-sensing concrete, including the principles such as piezoresistivity and piezopermittivity; the tunnelling effect, percolation threshold, and electrical circuit theories; the materials used and methods adopted; and the sensing parameters. The paper concludes with an outline of the application of self-sensing concrete and future recommendations, thus providing a better understanding of implementing the self-sensing technique in construction. [ABSTRACT FROM AUTHOR]

In order to develop a film electrode for the surface acoustic wave (SAW) devices working in high temperature, harsh environments, novel AlN/Pt/ZnO multilayers were prepared using pulsed laser deposition (PLD) systems on langasite (LGS) substrates. The AlN film was used as a protective layer and the ZnO buffer layer was introduced to improve the crystal quality of Pt films. The results show that the resistances of Pt and AlN/Pt film electrodes violently increase above 600 °C and 800 °C, respectively, while the resistances of AlN/Pt/ZnO electrodes have more stable electrical resistance from room temperature to 1000 °C. The AlN/Pt/ZnO electrode, where the ZnO film was deposited at 600 °C, has the best temperature stability and can steadily work for 4 h at 1000 °C. The mechanism underlying the stable resistance of the AlN/Pt/ZnO electrode at a high temperature was investigated by analyzing the microstructure of the prepared samples. The proposed AlN/Pt/ZnO film electrode has great potential for applications in high temperature SAW sensors. [ABSTRACT FROM AUTHOR]

Smart textiles have attracted huge attention due to their potential applications for ease of life. Recently, smart textiles have been produced by means of incorporation of electronic components onto/into conductive metallic yarns. The development, characterizations, and electro-mechanical testing of surface mounted electronic device (SMD) integrated E-yarns is still limited. There is a vulnerability to short circuits as non-filament conductive yarns have protruding fibers. It is important to determine the best construction method and study the factors that influence the textile properties of the base yarn. This paper investigated the effects of different external factors, namely, strain, solder pad size, temperature, abrasion, and washing on the electrical resistance of SMD integrated silver-coated Vectran (SCV) yarn. For this, a Vectran E-yarn was fabricated by integrating the SMD resistor into a SCV yarn by applying a vapor phase reflow soldering method. The results showed that the conductive gauge length, strain, overlap solder pad size, temperature, abrasion, and washing had a significant effect on the electrical resistance property of the SCV E-yarn. In addition, based on the experiment, the E-yarn made from SCV conductive thread and 68 Ω SMD resistor had the maximum electrical resistance and power of 72.16 Ω and 0.29 W per 0.31 m length. Therefore, the structure of this E-yarn is also expected to bring great benefits to manufacturing wearable conductive tracks and sensors. [ABSTRACT FROM AUTHOR]

This study analyzed the influence of carbon nanotubes (CNTs) on the carbonation conductive cementitious composites. Two powder types of CNT, multi-walled and single-wall CNTs, were employed to give the cement mortar the conductivity, and four tests including the accelerated carbonation, compressive and flexural strength, electrical resistance, and porosity tests were carried out. To intentionally accelerate the carbonation, the prismatic specimens of conductive cement composites were fabricated and stored in the controlled environmental chamber at a constant temperature of 20 ± 2 °C, constant relative humidity of 60 ± 5%, and carbon dioxide (CO2) concentration of 5% for 12 weeks. It was observed that carbonation resulted in only chemical damage so that there was no change in the electrical resistance value of conductive cementitious mortar that had undergone a carbonation attack. [ABSTRACT FROM AUTHOR]

Manufacturing processes for monofunctional and multifunctional materials vary depending on the design optimization. Multifunctional continuous carbon fiber composites provide great potential in achieving coupled structural and electrical properties for their applications in aircraft, unmanned aircraft systems, and spacecraft. Proper optimization of tensile and electrical properties offers benefits early in the design and continuous operational safety phases to obtain coupled multifunctional properties. In this paper, fused filament fabrication additive manufacturing (AM) technique was used to fabricate continuous carbon fiber solid laminated composites test coupons. The proposed new method characterizes the electrical conductivity's coupled effects on the tensile properties, including the failure loads and modes. This paper addresses a novel way of integrating electrical function into the composites that significantly reduce weight, potentially replacing the bulky electrical wires. Tensile and electrical conductivity tests were concurrently conducted on coupons, and the results were plotted and tabulated. The results showed the multifunctional properties of the maximum ultimate tensile strength of 392 MPa with the maximum tensile load of 8907 N, and resistance of 37.5 G·Ω. The average values for ultimate tensile strength and maximum load were 371 MPa and 8459 N, respectively. [ABSTRACT FROM AUTHOR]

A study of altering the conductive properties of wool fibers by applying copper selenide is presented. The researched modification of wool fibers was based on a two-stage adsorption-diffusion process. X-ray diffraction, scanning electron microscope, energy-dispersive X-ray spectrum, and Fourier transform infrared spectroscopy were performed to evaluate the morphological and physical characteristics of all CuxSe-coated wool fibers. X-ray diffraction (XRD) data showed a single, Cu0.87Se (klockmannite), crystalline phase present, while Atomic Absorption Spectroscopy (AAS) and Energy Dispersive X-ray (EDX) analyses showed that the concentrations of Cu and Se in copper selenide coatings depend on the number of wool fiber treatment cycles. It was determined that a dense layer of CuxSe grows through a nucleation mechanism followed by particle growth to fill out the complete surface. It was found that the conductivity of the coated wool fibers depends on the quality and density of the copper selenide coating, thus the resistance of electrically impermeable wool fibers can be reduced to 100 Ω by increasing the number of treatment cycles. [ABSTRACT FROM AUTHOR]

Acoustic emissions (AE) due to microcracking in solid materials permit the monitoring of fracture processes and the study of failure dynamics. As an alternative method of integrity assessment, measurements of electrical resistance can be used as well. In the literature, however, many studies connect the notion of criticality with AE originating from the fracture, but not with the changes in the electrical properties of materials. In order to further investigate the possible critical behavior of fracture processes in rocks and cement-based materials, we apply natural time (NT) analysis to the time series of AE and resistance measurements, recorded during fracture experiments on cement mortar (CM) and Luserna stone (LS) specimens. The NT analysis indicates that criticality in terms of electrical resistance changes systematically precedes AE criticality for all investigated specimens. The observed greater unpredictability of the CM fracture behavior with respect to LS could be ascribed to the different degree of material homogeneity, since LS (heterogeneous material) expectedly offers more abundant and more easily identifiable fracture precursors than CM (homogenous material). Non-uniqueness of the critical point by varying the detection threshold of cracking events is apparently due to finite size effects which introduce deviations from the self-similarity. [ABSTRACT FROM AUTHOR]

Given the drawbacks of the conventional welding methods in joining the battery case and tab in the lithium-ion battery, the laser welding technique using the metal tube has been introduced for the weld. The metal tube is supposed to contribute a positive effect including protection to the outside structure by blocking the injection of the spatters, and minimization of the contact gap between the battery case and table. However, the use of the metal tube is believed to cause the plume trapped inside and affect the intensity distribution of the laser gaussian beam. Through the observation and analysis in this study, both advantages and disadvantages of the application of the metal tube on the weld have been analyzed. The use of the metal tube prevents the ejection of the spatter to the outside of the welding zone, as well as minimize the air gap between the battery case and tab in the lap joint weld is also minimized. On the other hand, the trapped plume inside the metal tube and the reduction of the energy of the laser beam have been considered to cause significant changes in the morphology, mechanical, and electrical properties of the weld. [ABSTRACT FROM AUTHOR]

In continuous casting processes, inevitable voids (damage) are generated inside the material. The subsequent forming process of hot flat rolling offers the potential of healing these defects by closing the voids and bonding the internal surfaces. In this paper, different forming conditions from hot flat rolling process were characterized with micromagnetic measurement techniques and the influence of the damage evolution on the fatigue behavior was investigated. To characterize the reduction of voids through hot flat rolling processes, nondestructive testing techniques are required. Therefore, micromagnetic measurements such as Barkhausen noise, incremental permeability, and harmonic analysis were carried out, correlated with the number of voids, and compared with each other. The influence of damage evolution of different forming conditions on the fatigue behavior was characterized based on instrumented constant amplitude and multiple amplitude (load increase) tests. A significant increase in fatigue strength due to the hot flat rolling process, which leads to a reduction in the number of voids, was observed. In addition, the fracture surfaces of the specimens were analyzed in the scanning electron microscope. [ABSTRACT FROM AUTHOR]

Carbon-based particles, such as graphite and graphene, have been widely used as a filler in magnetorheological elastomer (MRE) fabrication in order to obtain electrical properties of the material. However, these kinds of fillers normally require a very high concentration of particles to enhance the conductivity property. Therefore, in this study, the nanosized Ni-Mg cobalt ferrite is introduced as a filler to soften MRE and, at the same time, improve magnetic, rheological, and conductivity properties. Three types of MRE samples without and with different compositions of Mg, namely Co0.5Ni0.2Mg0.3Fe2O4 (A1) and Co0.5Ni0.1Mg0.4Fe2O4 (A2), are fabricated. The characterization related to the micrograph, magnetic, and rheological properties of the MRE samples are analyzed using scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and the rheometer. Meanwhile, the effect of the nanosized Ni-Mg cobalt ferrites on the electrical resistance property is investigated and compared with the different Mg compositions. It is shown that the storage modulus of the MRE sample with the nanosized Ni-Mg cobalt ferrites is 43% higher than that of the MRE sample without the nanomaterials. In addition, it is demonstrated that MREs with the nanosized Ni-Mg cobalt ferrites exhibit relatively low electrical resistance at the on-state as compared to the off-state condition, because MRE with a higher Mg composition shows lower electrical resistance when higher current flow occurs through the materials. This salient property of the proposed MRE can be effectively and potentially used as an actuator to control the viscoelastic property of the magnetic field or sensors to measure the strain of the flexible structures by the electrical resistance signal. [ABSTRACT FROM AUTHOR]

This paper studies the effect of water as an oxidation agent and also of oxygen on zinc corrosion kinetics in active state in concrete, using high-sensitivity electrical resistance sensors. It was proven that zinc corrosion in active state is strongly affected by the presence of water at its surface. Zinc corrosion in real concrete in the absence of water can be misinterpreted as salt passivity. The presence of oxygen results in an increase of zinc corrosion rate, however at pH 12.6, passivity can occur. It was verified that corrosion products consisting primarily of Ca[Zn(OH)3]2·2H2O cannot effectively passivate zinc surface in concrete, even after 1800 h of exposure and zinc, or hot-dip galvanized steel can corrode at an unacceptable corrosion rate (more than 4 µm·a−1). [ABSTRACT FROM AUTHOR]

This study focuses on the effect generated by a compressive load, in the range 15%–60% of the ultimate load (Fu), in the chloride penetration rate of cement-based materials. The modifications produced in the microstructure influence the transport properties, and, thus, the validation of several interesting parameters, such as, the load value and the loading time, including both static and dynamic loading modes, was evaluated. This analysis was performed by impedance spectroscopy (IS), a non-destructive technique that allowed, after the appropriate modeling analysis, the assessment of the resistivity of the sample, a parameter that has been correlated to the diffusion coefficient in a previous investigation. The experimental arrangement was designed to allow the recording of the impedance spectra under the effect of a compressive load and, thus, the real-time monitoring of the chloride diffusivity was provided. An increase in the diffusion coefficient was verified for a load at 60%Fu whereas no variations were obtained for the load fixed at 30%. A relevant difference could be checked if the values were measured once the load was removed, showing the importance of the precise loading stage for the chloride diffusion study. [ABSTRACT FROM AUTHOR]