Al Layer Research Articles

Deep Ultraviolet Excitation Photoluminescence Characteristics and Correlative Investigation of Al-Rich AlGaN Films on Sapphire

AlGaN is attractive for fabricating deep ultraviolet (DUV) optoelectronic and electronic devices of light-emitting diodes (LEDs), photodetectors, high-electron-mobility field-effect transistors (HEMTs), etc. We investigated the quality and optical properties of AlxGa1−xN films with high Al fractions (60–87%) grown on sapphire substrates, including AlN nucleation and buffer layers, by metal–organic chemical vapor deposition (MOCVD). They were initially investigated by high-resolution X-ray diffraction (HR-XRD) and Raman scattering (RS). A set of formulas was deduced to precisely determine x(Al) from HR-XRD data. Screw dislocation densities in AlGaN and AlN layers were deduced. DUV (266 nm) excitation RS clearly exhibits AlGaN Raman features far superior to visible RS. The simulation on the AlGaN longitudinal optical (LO) phonon modes determined the carrier concentrations in the AlGaN layers. The spatial correlation model (SCM) analyses on E2(high) modes examined the AlGaN and AlN layer properties. These high-x(Al) AlxGa1−xN films possess large energy gaps Eg in the range of 5.0–5.6 eV and are excited by a DUV 213 nm (5.8 eV) laser for room temperature (RT) photoluminescence (PL) and temperature-dependent photoluminescence (TDPL) studies. The obtained RTPL bands were deconvoluted with two Gaussian bands, indicating cross-bandgap emission, phonon replicas, and variation with x(Al). TDPL spectra at 20–300 K of Al0.87Ga0.13N exhibit the T-dependences of the band-edge luminescence near 5.6 eV and the phonon replicas. According to the Arrhenius fitting diagram of the TDPL spectra, the activation energy (19.6 meV) associated with the luminescence process is acquired. In addition, the combined PL and time-resolved photoluminescence (TRPL) spectroscopic system with DUV 213 nm pulse excitation was applied to measure a typical AlGaN multiple-quantum well (MQW). The RT TRPL decay spectra were obtained at four wavelengths and fitted by two exponentials with fast and slow decay times of ~0.2 ns and 1–2 ns, respectively. Comprehensive studies on these Al-rich AlGaN epi-films and a typical AlGaN MQW are achieved with unique and significant results, which are useful to researchers in the field.

Multiple shock and acceleration processes of high-velocity flyers driven by the HEAVEN-I laser facility

The experiments of high-velocity flyer acceleration were performed on the HEAVEN-I KrF laser facility with a long-pulse duration (∼ 28 ns). Double-layered flyers consisting of polystyrene and aluminum films can be accelerated to more than 10 km/s measured by VISAR. The polystyrene layer is used as the ablative material, insulation layer, and shock wave regulator. Multiple shock and acceleration processes were observed by adjusting the thickness of the polystyrene layer. We simulated and analyzed the multiple shock processes driven by the long laser pulses and square pressure pulses. The results indicate that the reverberation processes can be induced by the alternating shock and rarefaction waves due to the wave–interface interactions. The reverberations in the Al layer can modulate the pressure evolution and the fine structure of flyer acceleration history. Similar processes in the polystyrene layer can lead to a secondary or multiple shock loading process when the driving pulse duration is several times longer than the shock round trip time in the double-layered flyer. Multiple accelerations can effectively enhance the final velocities in the experimental and simulation results. However, multiple accelerations involve more complex shock loading and unloading processes, and flyers are more prone to breakup compared with single acceleration.

AlN/AlGaN heterojunction field-effect transistors with a high-AlN-mole-fraction Al0.72Ga0.28N channel grown on single-crystal AlN substrate by metalorganic chemical vapor deposition

This paper presents research results on AlN/AlGaN heterojunction field-effect transistors (HFETs) with a high-AlN-mole-fraction Al0.72Ga0.28N channel grown on a single-crystal AlN substrate by metalorganic chemical vapor deposition. Material evaluation results confirmed that the grown AlGaN layer was 100% coherently grown for the underlying AlN substrate and thereby had superior crystal quality as well as the substrate. The fabricated AlGaN-channel HFETs with a gate length of 2 μm exhibited pinch-off characteristics with the max. current density (I DS_MAX) of 21 mA mm−1, the on-state resistance of 250 Ωmm, the peak transconductance of 4.5 mS mm−1 with the threshold voltage of –4.6 V, and the on/off ratio of 4 × 10−5. The temperature dependence of DC characteristics confirmed that the I DS_MAX decreased by 15% and the off-leakage current increased from 60 nA mm−1 to 10 μA mm−1 within the temperature range from room temperature to 200 °C.

An Experimental Investigations on Design and Weight Optimization for a Light Motor Vehicle (LMV) Drive Shaft Using a Composite Material Aluminum and Glass Fiber (Al + GF)

Aluminum is primarily used in Metal Composites because of its lighter weight and higher strength. Glass fibers are wound around an aluminum shaft to create the composite. ANSYS results determine the relative amounts of aluminum and Eglass fiber in each shaft. The purpose of this study is to use a torsion test to evaluate the mechanical performance of a composite shaft composed of aluminum and glass fiber. The results are carefully examined for different combinations of glass fiber layers and aluminum layers. When the weight proportion of aluminum in the composite increases, the mechanical properties of the composites improve.

Multianalyte Detection with Metasurface-Based Midinfrared Microspectrometer.

Midinfrared (2.5-25 μm) spectroscopy is an ideal tool for identifying chemicals in a nondestructive manner. The traditional platform is a Fourier transform infrared (FTIR) spectrometer, but this is too bulky, expensive, and power-hungry for many applications. There is therefore a growing demand for small, lightweight, and cost-effective microspectrometers for use in the field. One emerging platform is the filter-array detector-array microspectrometer. It pairs a broadband detector array with a thin and rigid array of spectral filters to offer a robust, compact platform for real-time in situ sensing. However, most demonstrations have only focused on identifying a single chemical against a null sample, even though many applications would involve multianalyte detection. In this work, we show a rare attempt at simultaneously tracking multiple analytes with a metasurface filter-array microspectrometer. The metasurface consists of periodic lattices of subwavelength circular apertures in an aluminum layer to create an array of bandpass filters. The filter array is imaged with an off-the-shelf microbolometer via a reverse-lens imaging setup to simultaneously monitor the concentration of ethanol and methanol in gasoline. This represents an important application of fuel quality monitoring. Chemometric models (PLS and SVR) are trained and tested on gasoline blends with ethanol and methanol contents, both ranging from 0% to 20% v/v. A support vector machine regression (SVR) model with a cubic kernel was found to have the lowest combined prediction errors. The root-mean-square-error of prediction (RMSEP) for ethanol and methanol are 1.23% and 1.84% v/v; the corresponding pseudounivariate limit of detection is found to be 4.22% and 6.86% v/v, respectively. This work takes the emerging field of metasurface-based mid-infrared spectrometers from single- to multianalyte detection, thereby considerably expanding their range of potential applications.

Nanostructures/TiN layer/Al2O3 layer/TiN substrate configuration-based high-performance refractory metasurface solar absorber

Metasurface solar absorber serves as a kind of important component for green energy devices to convert solar electromagnetic waves into thermal energy. In this work, we design a new solar light absorber configuration that incorporates the titanium nitride substrate, aluminum oxide layer, titanium nitride layer, and the topmost refractory nanostructures. The metasurface absorber based on this configuration can achieve an average spectral absorption of over 91% and a total solar radiation absorption of 91.5% at ultra-wide wavelengths of 300–2500 nm. It is discovered that the excellent performance of the proposed metasurface absorber is attributed to the synergistic effects of surface plasmonic effect and Fabry–Pérot (FP) cavity resonance by comprehensive analysis of the simulated field distributions. Furthermore, the effect of geometrical parameter of the proposed configuration on absorber performance is studied, indicating the proposed configuration possesses a large fabrication tolerance. Moreover, the proposed configuration is not sensitive to the polarization direction and the angle of incident light. It is also found that the use of other refractory metal materials and other shapes as the topmost absorbent nanostructures also have good results with this configuration. This work can offer a universal platform for constructing and guiding the design of refractory metasurface solar absorbers.

Interlayer growth of magnetic nanocomponent in Ti3C2Tx MXene EMW absorbers for periodic electromagnetic synergetic network

Transition metal carbides/carbonitrides (MXene) exhibit huge potential as electromagnetic wave (EMW) absorbers in dealing with electromagnetic radiation problem that rise due to the rapid development of 5G era. The incorporation of magnetic materials can effectively mitigate the impedance mismatch and singular loss mechanisms inherent in pure MXenes (PMs). However, challenges persist due to issues such as random distribution, complex preparation processes, and inadequate interaction. In this study, Ti3C2Tx/Ni hybrids were synthesized using a one-pot method, wherein Ni, derived from molten salt, replaces Al layer of MXene, facilitating the in-situ growth of Ni nanocomponents within the interlayered region. The periodic electromagnetic synergetic network of “MXene-Ni-MXene-Ni-MXene” provides substantial magnetic resonance, eddy current loss, interface polarization, defect polarization, and dipole polarization, enriching the loss mechanism. By regulating the concentration of Ni, the intrinsic poor impedance matching of MXene was improved. Consequently, Ti3C2Tx/Ni hybrid exhibited exceptional electromagnetic wave absorption (EMA) performance, achieving a reflection loss (RL) of −64.51 dB and an effective absorption bandwidth (EAB) of 4.96 GHz at a matching thickness of 1.98 mm. Additionally, the super radar cross-section (RCS value = −15.73 dB m2) endow it potential in practical application. This work provides a facile method for achieving unique electromagnetic synergetic loss mechanism, thus paving the way for exploring high-efficient MXene-based EMW absorbers.

Low Thermal Resistance of Diamond‐AlGaN Interfaces Achieved Using Carbide Interlayers

AbstractThis study investigates thermal transport across nanocrystalline diamond/AlGaN (aluminum gallium nitride) interfaces, crucial for enhancing thermal management in AlGaN‐based electronic devices. Chemical vapor deposition growth of diamond directly on AlGaN resulted in a disordered interface with a high thermal boundary resistance (TBR) of 20.6 m2‐KGW−1. Sputtered carbide interlayers of boron carbide (B4C), silicon carbide (SiC), and a mixture of boron carbide and silicon carbide (B4C/SiC) are employed to reduce thermal boundary resistance in diamond/AlGaN interfaces. The carbide interlayers resulted in record‐low thermal boundary resistance values of 3.4 and 3.7 m2‐KGW−1 for Al0.65Ga0.35N samples with B4C and SiC interlayers, respectively. STEM imaging of the interface reveals interlayer thicknesses between 1.7 and 2.5 nm, with an amorphous structure. Additionally, Fast‐Fourier Transform (FFT) characterization of sections of the STEM images displayed sharp crystalline fringes in the AlGaN layer, confirming it is properly protected from damage from hydrogen plasma during the diamond growth. In order to accurately measure the thermal boundary resistance we develop a hybrid technique, combining time‐domain thermoreflectance and steady‐state thermoreflectance fitting, offering superior sensitivity to buried thermal resistances. The findings underscore the efficacy of interlayer engineering in enhancing thermal transport and demonstrate the importance of innovative measurement techniques in accurately characterizing complex thermal interfaces. This study provides a foundation for future research in improving thermal properties of semiconductor devices through interface engineering and advanced measurement methodologies.

Tuning the geometry of porous alumina layers via anodization in mixtures of different acids

AbstractPorous anodic aluminum oxide (AAO) layers have been obtained by two-step anodization of high-purity Al in two types of acid mixtures, i.e., in H2C2O4–H3PO4 and, for the first time, in H2SO4–H3PO4 systems. The kinetics of oxide formation was examined by monitoring the current vs. time curves while the morphology of the resulting layers was carefully verified by scanning electron microscopy (SEM). A special emphasis was put on establishing correlations between electrolyte composition, the kinetics and effectiveness of oxide growth, and the morphological features of AAO layers (pore and cell diameter, porosity), as well as pore arrangement. It was confirmed that the addition of H3PO4 to both H2C2O4 and H2SO4 electrolytes results in a significant decrease in oxide growth rate, and worsening of pore arrangement, while the values of pore diameter and interpore distance are much less affected. Moreover, the presence of a small amount of phosphoric acid in the reaction mixture allowed for a noticeable increase in pore ordering if anodization was carried out beyond the self-ordering regime, or performing controlled anodization even at voltages at which the burning phenomenon is typically observed. It is strongly believed that manipulating the electrolyte composition by adding another acid may provide another degree of freedom to control the morphology of the resulting nanostructured alumina layers.

Investigation on barrier layers of Pt/BaTiO3/Pt based thin film capacitors

Barium titanate is a ferroelectric material used as a dielectric in thin film capacitors owing to its high dielectric constant. Barrier layers are utilized in these capacitors to improve the capacitors' performance. In this paper, zinc oxide and aluminium oxide are kept on both sides of BaTiO3 as barrier layers in Pt/BT/Pt capacitors and different dielectric properties are studied. The parameters such as capacitance density, leakage current, ESR, dielectric loss and dielectric strength of Pt/BT/Pt capacitors with barrier layers of different sizes are simulated using COMSOL Multiphysics modeling software. Aluminum oxide of 2 nm thickness as a barrier layer gives optimal performance. The leakage current, dielectric loss, capacitance density, equivalent series resistance and dielectric strength of Pt/BT/Pt capacitor are found to be 0.519 mA, 9.62x10‐12, 172.8 fF/µm2, 9.62 kΩ, 108 V/m respectively whereas that of Pt/ALO/BT/ALO/Pt capacitor are found to be 1.56x10‐18A, 7.81x10‐18, 11.6 fF/µm2, 9.01x1015 Ω, 5.05x109 V/m respectively. The low capacitance in Pt/ALO/BT/ALO/Pt capacitor is due to the low dielectric constant of Al2O3 layer. The reduced leakage current and increased equivalent series resistance is due to the low conductivity of the Al2O3 layer. The use of aluminium layer can reduce the electric field leading to improved dielectric strength.

Large Chiral Orbital Texture and Orbital Edelstein Effect in Co/Al Heterostructure.

Recent experiments by S. Krishnia et al. [Nano Lett. 2023, 23, 6785] reported an unprecedentedly large enhancement of torques upon inserting thin Al layer in Co/Pt heterostructure that suggested the presence of a Rashba-like interaction at the metallic Co/Al interface. Based on first-principles calculations, we reveal the emergence of a large helical orbital texture in reciprocal space at the interfacial Co layer, whose origin is attributed to the orbital Rashba effect due to the formation of the surface states at the Co/Al interface and where spin-orbit coupling is found to produce smaller contributions with a higher-order winding of the orbital moments. Our results unveil that the orbital texture gives rise to a nonequilibrium orbital accumulation producing large current-induced torques, thus providing an essential theoretical background for the experimental data and advancing the use of orbital transport phenomena in all-metallic magnetic systems with light elements.

Spectral and optic-metric methods of monitoring parameters of plasma channels caused by discharge currents between metals granules in working liquids

Introduction. Spark-erosion processing of metals and alloys granules in working liquids is the basis of a several technological processes. Efficiency of energy use in them and parameters of the resulting product largely depend on the accuracy of stabilization and regulation of pulse power in each plasma channel between the granules. To achieve this, until now only the voltage and current of the discharge pulses in the entire layer of granules have been controlled. Problem. The measurement methods, which are used, are not effective enough for monitoring the parameters of individual plasma channels and predicting the size distribution of eroded metals particles at the stage of their formation. The aim of the work is to develop a method for determining the volumes of components of plasma channels in layers of metals granules during their spark-erosion treatment to predict the size distribution of eroded metal particles at the stage of their formation, as well as to simplify the method of spectrometric analysis of the elemental composition of substances surrounding plasma channels for the operational prediction of the chemical composition of resulting products. Methodology. A series of experiments were carried out on spark-erosion processing of Al and Ag granules layers in distilled water. Using a digital camera, images of the plasma channels in them were obtained. Based on the theory of pulsed electrical breakdown of liquid dielectrics, an analysis of the components of plasma channels was carried out. Using the specialized ToupView program, the volumes of equivalent ellipsoids of rotation were determined, approximating the halos of colored radiation likely arising from streamers, as well as the spark cores of plasma channels emitting white light. The shades of the resulting radiation were studied for several metals and working liquids. The obtained data were compared with the known results of spectrometric studies for the same elements excited by similar mechanisms. Results. The theory of discharge-pulse systems for spark-erosion processing of granular conductive media has been developed in the direction of new methods for monitoring the parameters of discharge pulses and predicting the chemical composition and size distribution parameters of eroded metal particles at the stage of their production. An optic-metric method has been developed for determining the volumes of halos and cores of plasma channels. A simplified spectral method for determining the chemical composition of erosion particles based on the shade of the resulting radiation was proposed. Originality. The developed new optic-metric method makes it possible to obtain information about almost every plasma channel, which refines predictions of the size distribution of erosion particles. To implement the method, general-purpose hardware and specialized software that is freely available are used. The developed method of simplified spectral analysis of excited atoms makes it possible to make preliminary predictions of the chemical composition of the obtained erosion particles already at the stage of their formation without the use of expensive specialized equipment. Practical significance. The ratio of the volumes of halos and cores of plasma channels between Al and Ag granules in distilled water was measured. An analysis of the emission spectra of plasma channel halos between Al, Ag and Cu granules in distilled water, Fe in ethyl alcohol, Ni-Mn-Ga and Ti-Zr-Ni alloys in liquid nitrogen, and Ti-Zr-Ni in liquid argon was carried out. Based on spectrometry data, the resulting shades of these radiations were substantiated and their description in the RGB system is given. References 56, table 1, figures 4.

A Viability Study of Thermal Pre-Treatment for Recycling of Pharmaceutical Blisters

Pharmaceutical packaging is one of the most used packaging types which contains aluminum and plastics. Due to increasing amounts of waste and rising environmental concerns, recycling approaches are being investigated. Since blisters usually contain a balanced amount of plastics and metals, most of the approaches focus on recycling only one material. Therefore, more sustainable recycling approaches which recover both plastic and aluminum fractions are needed. This study investigates the thermal behavior and degradation mechanisms of plastic-rich and aluminum-rich pharmaceutical blisters using various analytical techniques. Structural characterization revealed that plastic-rich blisters have a thicker profile with plastic and aluminum layers, while aluminum-rich blisters consist of plastic layers between aluminum sheets. Thermal degradation analysis showed two main stages for both types: plastic-rich blisters (polyvinyl chloride) exhibited significant weight loss and long-chain hydrocarbon formation between 210 and 285 °C, and aluminum-rich blisters (polyamide/nylon) degraded from 240 to 270 °C. Differential Scanning Calorimetry and Fourier Transform Infrared Spectroscopy analyses confirmed the endothermic behavior of such a transformation. The gas emissions analysis indicated an increased formation of gasses from the thermal treatment of plastic-rich blisters, with the presence of oxygen leading to the formation of carbon dioxide, water, and carbon monoxide. Thermal treatment with 5%O2 in the carrier gas benefited plastic-rich blister treatment, reducing organic waste by up to 80% and minimizing burning risk, leveraging pyrolytic carbon for protection. This method is unsuitable for aluminum-rich blisters, requiring reduced oxygen or temperature to prevent pyrolytic carbon combustion and aluminum oxidation.

Направления совершенствования сероочистки, осушки и переработки природного газа

The results of the work of the staff of the Department of “Chemical Technology of Oil and Gas Refining” of Astrakhan State Technical University in the field of separation of three-phase reservoir mixture, increasing the efficiency of desulfurization, improving the process of drying gas and the production of continuous hydrocarbons – raw materials for petrochemistry. The influence of the quality of raw materials entering processing on the formation of deposits in technological equipment has been studied. Reconstruction of the inlet and three-phase separators of high-pressure reservoir mixture separation plants by installing a vibration damper and a depulsor on the reservoir mixture supply line to the installation, as well as reconstruction of the input of raw materials into the separator of the installation. The use of the KPG-200 defoamer and the KPG-200 AV antifoamer made it possible to reduce the consumption rate of defoaming reagents several times in gas purification plants from acidic components. The influence of various impurities on the foaming of working amine solutions (mechanical impurities, coal dust, products of thermal destruction of amine, thermostable salts, corrosion inhibitors) has been determined. It was revealed that the products of thermal degradation of amine have the greatest effect at concentrations above 3% by weight. A method for reducing the content of mechanical impurities in a solution of diethanolamine in a constant magnetic field has been developed and introduced into an industrial desulfurization plant. The filtration efficiency increases 2.6 times, the foam height is halved, and the foam stability is quadrupled. At the same time, the activity of the defoamer increases by 1.7 times. The mathematical dependence of the height of the protective layer of aluminum oxide in an adsorber with zeolite on impurities of diethanolamine has been experimentally found. The effectiveness of the developed improved distribution ring device is shown, the use of which makes it possible to practically eliminate dead zones in the zeolite layer and thereby increase the efficiency of the adsorption process and increase the inter-regeneration period on the drying unit. Studies of the catalytic pyrolysis of the butane fraction using CVM-type pentasils modified with the introduction of chromium can reduce the process temperature compared with the thermal decomposition of raw materials by more than one hundred degrees 100 °C.

Transport of non-equilibrium quasiparticle excitations in superconducting aluminum

The electron transport of non-equilibrium quasiparticles injected into superconducting aluminum from a normal metal has been experimentally studied at ultralow temperatures. We studied hybrid nanostructures in the form of a T-shaped normal metal electrode (copper) – a dielectric tunnel layer (aluminum oxide) – a superconducting fork (aluminum), which can be considered as a solid-state analogues of a two-beam optical interferometer. At fixed bias voltages larger than the superconducting gap, a non-monotonic dependence of the tunnel current on perpendicular magnetic field is observed. The effect is interpreted as the presence of a coherent component of the quasiparticle current.

Fabrication of optimized partial-reflection coatings for mid-infrared quantum cascade lasers

This study presents both numerical modeling and experimental fabrication of three different partial-reflection (PR) coatings each optimized for quantum cascade lasers (QCLs) that emit radiation in the mid-infrared range. A novel double-layer PR coating comprising silicon dioxide (SiO2) and silicon nitride (Si3N4) was proposed as a potential solution for compatibility with QCLs fabrication processes. Subsequently, the PR coating was compared with two well-known PR coatings: a single layer of aluminum oxide (Al2O3) and a single layer of yttrium oxide (Y2O3). The coatings were designed to reduce the reflectivity of the front laser mirror from 30% to approximately 13%. The thickness of the dielectric layers was optimized for lasers emitting at 4.4 μm, with applicability in the 2.5–6 μm range. The proposed double-layer coating achieved the desired reflectivity while reducing the total coating thickness by 120 nm. By using the presented coatings it will be possible to increase the optical power of Mid-Infrared QCLs.

Microstructure and properties of C18150 Cu/8011 Al/C18150 Cu laminated composites

In order to solve the problem of insufficient strength and electrical conductivity of Cu–Al composites, C18150 Cu/8011 Al/C18150 Cu composites with a thickness of 1.6 mm were fabricated by cast rolling method in this paper, followed by cold rolling and annealing. The interfacial microstructure and precipitation behavior were analyzed through electron backscatter diffraction, scanning electron microscopy, and transmission electron microscopy in detail. The research results show that the three-layer interfaces from the Al layer to the Cu layer are Al2Cu, AlCu, and Al4Cu9, respectively. The interface of the Al layer and Al2Cu layer demonstrate a coherent matching relation, the interface of the Al2Cu layer and AlCu layer shows a semi-coherent matching relation, and the interfaces between AlCu and Al4Cu9, and Al4Cu9 and Cu, are incoherent matching relation. In addition, the Al2Fe3Si4 and Cr precipitations were formed in the composites. The composites exhibit extremely outstanding strength-plasticity-conductivity, and the tensile strength and elongation are 295 MPa and 21%, respectively. The electrical conductivity of the Cu and Al layers is 90.6% and 47.6% according to the International Copper Standard, respectively. This study is useful in guiding the further development and application of high-strength and high-conductivity Cu/Al laminated composites.

Theoretical investigations of two-dimensional intrinsic magnets derived from transition-metal borides M3B4 (M = Cr, Mn, and Fe)

ABSTRACT Two-dimensional (2D) magnetic materials with high critical temperatures (T C ) and robust magnetic anisotropy energies (MAE) hold significant potential for spintronic applications. However, most of 2D magnetic materials are derived from the van der Waals (vdW) layered bulks, which greatly limits the synthesis of 2D magnetic materials. Here, 2D M3B4 (M = Cr, Mn, and Fe; B = Boron), derived from hexagonal and orthorhombic M3AlB4 phases by selectively etching Al layers, was studied for its structural stability, electronic structure, and magnetic properties. By utilizing ab initio calculations and Monte Carlo simulations, we found that the orthorhombic Cr3B4 shows ferromagnetic (FM) metal and possesses an in-plane magnetic easy axis, while the remaining hexagonal and orthorhombic M3B4 structures exhibit antiferromagnetic (AFM) metals with a magnetic easy axis which is perpendicular to the two-dimensional plane. The critical temperatures of these 2D M3B4 structures are found to be above the 130 K. Notably, the ort-Mn3B4 possesses highest T C (~600 K) and strongest MAE (~220 µeV/atom) among these borides-based 2D magnetic materials. Our findings reveal that the 2D M3B4 compounds exhibit much better resistance to deformation compared to M2B2 MBenes and other 2D magnetic materials. The combination of high critical temperature, robust MAE, and excellent mechanical properties makes 2D Mn3B4 monolayer exhibits a favorable potential for spintronic applications. Our research also sheds light on the magnetic coupling mechanism of 2D M3B4, providing valuable insights into its fundamental characteristics.

EVOLUTION OF THE PRESS BONDING PROPERTIES OF Al/Cu BIMETAL BULK COMPOSITES (EXPERIMENTAL AND NUMERICAL INVESTIGATION)

Nowadays, the application of bimetallic laminates with special capabilities is increasing and has experienced high growth. These properties include high corrosion resistance, mechanical properties, thermal stability, and lightweight. In the midst of 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 generate a suitable mechanical connection and strong bonding between produced metal layer components. In this study, bimetal aluminum/copper bulk composites have been fabricated via the APB technique. Then, the effect of pressing parameters such as plastic strain and the number of layers on the stress distribution has been investigated. For samples with eight layers, the shear stress between the layers reached 3.1 MPa which is a suitable condition to generate a successful bonding. The stress applied on the layers has also increased with increasing the thickness reduction ratio. The interlayer shear stresses also increase with decreeing the thickness. With a higher reduction in thickness ratios, the amount of sinking layers was greater along the entire length of the sample, which led to the crushing of copper layers. During the APB process at higher pressing passes, increasing the volume of virgin material in the direction of the press led to increasing the compaction and better bonding of Al and Cu layers to each other.

Exploring the nanobiohybrids of nanodiamonds-functionalized MoAlB@MBene and microalgae synergistic potential for sustainable pharmaceutical removal

Nanobiohybrid systems combine nanomaterials and biological components, creating synergistic platforms for diverse applications. We successfully developed MoAlB@MBene core-shell structure using HCl/H2O2 mixture, transforming the densely packed nanolaminar MoAlB MAB phase into an expanded multilayered MBene’ structure, featuring open slit-shaped pores. EDS and XRF analysis suggested that the voids between the Mo-B layers were due to the removal of approximately one aluminum layer. The etching of the MAB phase also caused a transition in the zeta potential from 1.11 to −3.35. Such characteristics suggest a potential for MBene’ surface functionalization. SEM and EDS confirmed that functionalization with 1.0 wt% fluorescent nanodiamonds (FND) was optimal, and guaranteed uniform distribution of the FND. Functionalization with FND ensured favorable optical properties, including fluorescence in the orange/red region and reduced direct band gap value (from 1.32 eV to 0.54 eV). The presence of FND mitigated the ecotoxicological properties of MoAlB@MBene. We observed sustained proliferation even at a concentration of 500 mg L−1 of the nanocomposite, with toxicity plateauing after 48 h of incubation. Optimization of encapsulation with sodium alginate suggested the best concentration (1.5 wt%) and cross-linking time (10 min), allowing for structural integrity, sphericality, and rapid microalgae growth. The fluorescent nanocomposite within encapsulated microalgae improved the decomposition rate of tetracycline (18 vs 45%) and doxycycline (14 vs 48%), achieving almost threefold enhancement within 24 h. Furthermore, it positively influenced microalgae growth, counteracting pharmaceuticals toxic effects. Altogether, these findings provide insights into developing and maintaining nanobiohybrid systems, incorporating fluorescent nanocomposite and microalgae, combining the knowledge from environmental protection and materials science.