Al Layer Research Articles

Water-Soluble Alumina-Coated Indium Phosphide Core-Shell Quantum Dots with Efficient Deep-Red Emission Beyond 700nm.

Solution-processed colloidal III-V semiconductor-based quantum dots (QDs) represent promising and environmentally-friendly alternatives to Cd-based QDs in the realms of optoelectronics and biological applications. While InP-based core-shell QDs have demonstrated efficientlight-emitting diode (LED) performance in the visible region, achieving deep-red emission (above 700nm) with a narrow linewidth has proven challenging. Herein, the study presents a novel strategy for synthesizing InP/ZnSe/ZnS core-shell-shell QDs tailored for emission in the first biological transparency window. The resulting QDs exhibit an emission wavelength up to 725nm with a narrow peak full width at half maximum (FWHM) down to 107 meV (45nm). To enhance the biocompatibility and chemical stability of the QDs, their surface is further capped with a layer of amorphous alumina resulting in an InP/ZnSe/ZnS/Al2O3 heterostructure. This surface passivation not only ensures environmental- and photostability but also enhances the photoluminescence quantum yield (PLQY). The alumina capping enables the aqueous phase transfer via surface ligand exchange using mercaptopropionic acid (MPA) while maintaining the initial quantum yield. The resulting QDs demonstrate a significant potential for advancing next-generation optoelectronic technologies and bio-applications.

Development of a fast neutron monitoring detector for the NDPS neutron TOF facility by using Parallel Plate Avalanche Counters

A Parallel Plate Avalanche Counter (PPAC) neutron monitoring detector was developed and manufactured to monitor fast neutrons with energies greater than ∼1 MeV for use in the Nuclear Data Production System (NDPS), a neutron Time-of-Flight (TOF) facility of RAON. The detectors designed for monitoring fast neutrons comprise two sets of PPACs and a fast neutron converter. The performance of the detector was tested by using a241Am alpha source and neutron beams from a proton cyclotron. For the fast neutron converter, a thin thorium coating with a diameter of 60 mm was prepared by using the electrodeposition method. The areal density of thorium deposited on a thin aluminium layer with a thickness of 2 μm was determined by alpha spectrometry and measured to be 306 ± 7.65 μg/cm2. For the neutron beam test, neutrons were generated through the 9Be (p,n)9B reaction in a proton cyclotron facility. These generated neutrons were detected by using our PPAC neutron detector, and the experimentally measured count rate (1.74 ± 0.18 counts/s) agreed with the count rate (1.68 counts/s) calculated by PHITS v3.16 and GEANT4 v10.7 simulations. The timing resolution of the detector was estimated to be σ = 550 ps.

Deep insight of inter-channel coupling in AlGaN/GaN double channel HEMT and its application in C-ERB2 sensing

AlGaN/GaN Double Channel High Electron Mobility Transistors (DCHEMTs) have emerged as promising biosensors, leveraging the unique properties of inter-channel coupling. This paper investigates the influence of mole fraction variations in the AlGaN layer on inter-channel coupling and explores its implications for C-ERB2 biosensing. The study reveals the potential of inter-channel coupling to enhance sensitivity in biosensing applications, particularly for detecting C-ERB2, a crucial protein associated with various cancers. The device architecture, simulation models, electrostatics, and sensitivity analysis are comprehensively examined. The findings underscore the significance of inter-channel coupling in optimizing biosensor performance, offering valuable insights for the advancement of biosensing technologies.

Emerging Two-Dimensional Ti3C2-BiOCl Nanoparticles for Excellent Antimicrobial and Antioxidant Properties.

Introduction MXenes (Ti3C2) represent a group of two-dimensional inorganic compounds, produced through a top-down exfoliation method. They comprise ultra-thin layers of transition metal carbides, or carbonitrides, and exhibit hydrophilic properties on their surfaces. Utilizing Ti3C2 BiOCl nanoparticles for their antimicrobial and antioxidant attributes involves enhancing synthesis, processing, and characterization techniques. Materials and method To prepare Ti3C2 MXene, dissolve 1.6 g of LiF in 20 ml of 9M HCl. Slowly add 1 g of Ti3AlC2(titanium aluminum carbide) powder to the solution while stirring. Etch at 35°C for 24 h to remove Al layers from Ti3AlC2, leaving Ti3C2 layers. Wash the mixture with distilled water and ethanol until the pH is around 6. Collect the washed sediment by centrifugation and sonicate it in distilled water for 1 h. Centrifuge to remove unexfoliated particles. For BiOCl synthesis, dissolve 2 mmol of Bi(NO3)3·5H2O (bismuth nitrate pentahydrate) in 10 ml of 2M HCl (hydrochloric acid) with 0.5 g of PVP (polyvinylpyrrolidone). Transfer the solution to a Teflon-lined autoclave, fill it with distilled water up to 80%, and heat at 160°C for 24 h. Collect the precipitate by centrifugation, wash, and dry at 60°C for 12 h. Disperse BiOCl nanoparticles in distilled water, sonicate for 30 min, add Ti3C2 MXene dispersion, stir for 2 h, collect, wash, dry, and calcine at 400°C for 2 h. Result The Scanning Electron Microscope (SEM) utilizes electrons, rather than light, to generate highly magnified images. Energy Dispersive X-ray Spectroscopy (EDS) complements SEM by analyzing the X-ray spectrum emitted when a solid sample is bombarded with electrons, enabling localized chemical analysis. In SEM imaging, incorporating an X-ray spectrometer allows for both element mapping and point analysis. The SEM image of the prepared samples reveals accordion-like multilayer structures in BiOCl, characterized by thin sheet-like structures with numerous pores. EDS, relying on X-ray emissions from electron bombardment, facilitates detailed chemical analysis at specific locations within the sample. Conclusion Our research has shed light on the synthesis and characterization processes of two-dimensional Ti3C2 BiOCl nanoparticles, revealing their remarkable antimicrobial and antioxidant properties.

Design and preparation of Ta33W35Cr15V17 /Al2O3 nano multilayer film based on multi-level construction strategy and its radiation resistance behavior

The microstructure and mechanical properties of Ta33W35Cr15V17/Al2O3 nano-multilayer films with preset defects after He+ ion irradiation were studied to understand the effects of layer interfaces and nano-defects. After irradiation, the growth of He bubbles in the alumina layer was confined to the nanovoids without aggregations. The nanochannel in the high-entropy alloy layer absorbed the deposited energy of He+ and shrank to disappear. In addition, the film was softened after irradiation due to the presence of presetting defects. Based on which a dual absorption source model of interface and pre-set defects was proposed to explain the enhancement of radiation tolerance.

Failure analysis of Fiber Metal Laminate channel section column under axial compressive pulse loading

The study aims to analyse the dynamic buckling phenomenon and assess the role of the stress tensor components in the failure process of a short Fiber Metal Laminate column under axial compressive dynamic loading. The investigation is focused on a channel-section profile composed of three aluminium layers and two doubled composite plies [Al/0/90/Al/90/0/Al]. The numerical analysis was performed on the finite element model, which was validated by experimental static buckling tests. Employing a progressive failure algorithm, this analysis incorporated the material property degradation method and Hashin’s criterion as the damage initiation criterion. Failure initiation in metal layers was based on the HuberMises-Hencky failure criterion. Based on the conducted analyses, it was concluded that the dominant forms of destruction in the FML structure are yielding in the metal layers due to excessive compressive stresses and the failure of the matrix in composite plies as a result of compressive and shear stresses. Through a thorough examination of the stress tensor components, critical stresses contributing to aluminum plastic deformation and laminate failure mechanisms were identified.

Forming Limits Prediction of Laminated SUS430/Al1050/SUS430 Composites and the Effect of Component Properties on Mechanical Performance

In this study, a constitutive model applied to predict the tensile properties and fracture behavior of well‐bonded multilayered metal composites is extended. The equivalent single‐layer model, as a convenient method, is introduced into finite‐element simulations by combining it with an improved Xue–Wierzbicki damage plasticity model that considers material anisotropy. The steel use stainless (SUS) 430/Al1050/SUS430 laminated sheet fabricated by cold rolling is selected as the research material. The quasistatic uniaxial tests and Nakazima tests are operated to verify the accuracy of the proposed method. The mean errors in tensile stress and fracture forming limit strains are 2% and 3%, respectively. A load‐sharing mixture rule is proposed to assess the effects of the volume fraction, strength coefficient, and hardening exponent of the constituent materials on the mechanical properties of the laminates. In the results, it is indicated that the laminate exhibits sufficient elongation and remains markedly enhanced in tensile strength, reaching 470 Mpa when the ductile Al layer is combined with the higher strength and hardenability steel layer. In this research, it is aimed to clarify the formability characteristics in laminated composites for optimal sheet configuration design and development.

Improvement of electrical performance in Normally-Off GaN MOSFET with regrown AlGaN layer on the Source/Drain region

A normally-off GaN MOSFET is successfully fabricated by using the selective regrowth technique (SRT) with regrown AlGaN layer on source/drain (S/D) region. The GaN MOSFET with regrown AlGaN layer and Lg of 10 μm shows enhanced electrical performance such as maximum drain current (ID,max) of 57 mA/mm, maximum transconductance (gm,max) of 11 mS/mm, and field-effect mobility (μFE) of 59 cm2/V·s, respectively, compared to the GaN MOSFET with n+-GaN selective regrowth in S/D region. This is because of the high 2DEG density formed by AlGaN/GaN heterojunction in S/D region. Moreover, to accommodate the poor structural quality of the narrow region regrowth of AlGaN layer on the S/D region, wide regrown AlGaN layer is applied to the GaN MOSFET. Especially, the off-state breakdown voltage improves from 25 V to 192 V with the improved structural quality of wide regrown AlGaN layer and optimized structure and the application of the 70-nm thick SiO2 passivation. These result shows that GaN MOSFET with wide regrown AlGaN layer on S/D region is beneficial to achieving high-quality and uniform normally-off GaN MOSFETs with excellent electrical performance.

In situ preparation of aluminum-copper pentafluorobenzoate energy microspheres: Enhancing aluminum combustion properties in composite propellants

Aluminum powder is the main metal fuel in composite propellants, and upgrading the proportion of aluminum powder loaded in solid propellants is currently one of the most effective means of increasing propellant energy. Nonetheless, the substantial disparity in boiling points between the core aluminum particles and the alumina layer enveloping their surfaces often results in reduced reactivity, inadequate combustion, and combustion agglomeration during the combustion process of the aluminum powder. Herein, copper pentafluorobenzoate (CuPF) interfacial layer was established on the surface of aluminum powder through the self-assembly coordination reaction between pentafluorobenzoic acid and copper ions, and Al-CuPF energy microspheres were successfully prepared. A comprehensive examination was carried out to scrutinize the surface morphology, elemental composition, and distribution of the Al-CuPF energy microspheres. Furthermore, meticulous studies were conducted on the ignition and combustion properties of these Al-CuPF energy microspheres under various atmospheric conditions. It was found that the Al-CuPF interfacial layer within the Al-CuPF energy microspheres plays a pivotal role in enhancing ignition initiation and acting as a catalyst to facilitate the more efficient combustion of aluminum powder. Moreover, the combustion behavior of Al-CuPF energy microspheres when integrated into composite propellants has been exhaustively researched. Notably, composite propellants incorporating Al-CuPF energy microspheres exhibit heightened burning temperatures and an increased burning rate. Additionally, the combustion and agglomeration dynamics of Al-CuPF energy microspheres on the propellant burning surface were meticulously documented using a high-speed camera. The findings revealed that Al-CuPF energy microspheres spend a significantly shorter duration on the propellant burning surface and notably mitigate the occurrence of aluminum agglomeration issues thereon. This research contributes fresh insights into the application of innovative aluminum-based fuels within the realm of composite propellants.

Experimental and numerical investigations on impact response of reinforced concrete beams with a sandwich panel protective layer

This paper investigates the response of reinforced concrete beams protected by an aluminium foam sandwich panel under impact loadings. A series of impact tests were conducted on one reinforced concrete beam and five beams with a protective layer, focusing on their dynamic responses and failure patterns. Test parameters included the type of protective layers (unprotected, aluminium foam and sandwich panel) and impact energy. Test results showed that the aluminium foam and sandwich panel could effectively protect the reinforced concrete beam from severe damage under impact loadings and converted the failure pattern of beams from shear failure to flexure-shear failure. Compared with the unprotected beam, the beams with a protective layer exhibited a lower peak force and developed a smaller mid-span deformation. Besides, the protective effects of the aluminium foam and sandwich panel were found to be nearly the same. Moreover, the peak force, plateau force and deformation of the beams were increased with the increasing impact energy. A numerical model was developed to investigate the energy distribution of beams with a sandwich panel protective layer. Based on the validated model, the effects of longitudinal reinforcement ratio and shear-span ratio on the impact response of beams were further studied. It was found that the deformation of beams increased significantly with the increasing shear-span ratio, whereas an increase in the longitudinal reinforcement ratio led to a decreased deformation. This study provides an important reference for designing reinforced concrete beams with a sandwich panel protective layer to resist impact loads.

Unlocking the Potential of Liquid Plasma Polymer Films: Characterizing Aging Effects and Their Impact on the Wrinkling Phenomenon.

Here, we present the study of the intricate dynamics between the physicochemical properties of liquid propanethiol plasma polymer films (PPFs) and the formation of wrinkles in PPF/Al bilayers. The study investigates the effect of liquid PPF aging in the air before top Al layer deposition by magnetron sputtering on the wrinkling phenomenon for 4 days. Thanks to atomic force microscopy, the wrinkle dimensions were found to decrease by approximately 55% in amplitude and 66% in wavelength, correlated with an increase in the viscosity of the PPF over the aging duration (i.e., from less than 107 to 1010 Pa·s). This behavior is not linked to alterations in cross-linking degree as evidenced by time-of-flight secondary ion mass spectrometry experiments but rather to network densification driven by the inherent molecular chain mobility due to the viscous state of the PPF. X-ray photoelectron spectroscopy measurements emphasizing the absence of oxidation of the PPF over the aging duration support this, revealing a unique aging mechanism distinct from other plasma polymer families. Overall, this study offers valuable insights into the design and application of mechanically responsive PPFs involved in bilayer systems, paving the way for advancements in nanotechnology and related fields.

Kinetics of diffusion and phase formation in a solid-state reaction in Al/Au thin films

The kinetics of diffusion and formation of Al-Au intermetallic compounds in a solid-state reaction between layers of aluminum and gold has been studied by the method of in situ electron diffraction. The phase sequence in the solid-state reaction in Al/Au thin films is found to depend on the atomic ratio of aluminum and gold at the initial state. Specifically, with the atomic ratio being Al:Au=2:1, one observes the formation sequence: Al3Au8→AlAu2→Al2Au, while with the ratio Al:Au=1:4, the sequence is Al3Au8→AlAu4. The observed change in the sequence is explained using the theoretical model of EHF (Effective Heat of Formation). The kinetic parameters of the diffusion of gold through the layer of reaction products in the Al/Au thin films have been determined, including the apparent activation energy of the diffusion Ea=1.17 eV and pre-exponential factor D0=120 cm2/s. Based on the data obtained by in situ electron diffraction, the kinetic parameters of the phase formation have been estimated by the Kissinger-Akahira-Sunose method. In addition, the kinetic parameters of the formation of the Al-Au intermetallic compounds have been determined (apparent activation energy Ea, pre-exponential factor A) in the solid-state reaction in the Al/Au thin films, namely, Ea = 0.77 eV, log(A, s−1) = 9 for Al3Au8; Ea = 1.08 eV, log(A, s−1) = 13 for AlAu2; Ea = 1.13 eV, log(A, s−1) = 13 for Al2Au; and Ea = 1.35 eV, log(A, s−1) = 16 for the phase AlAu4. The kinetic parameters of the formation of the AlAu4 phase have been estimated for the first time.

Synthesis and Application of Titanium Carbide (Ti3C2)-Cobalt Sulfide (Co3S4) Nanocomposites in Amino Acid Biosensing.

Background The fabrication of titanium carbide (Ti3C2)-cobalt sulfide (Co3S4)-based biosensors with high sensitivity and selectivity can change the biosensor manufacturing industry completely. Molecular and clinical diagnostics, disease progression monitoring, and drug discovery could utilize these sensors for early biomarker detection. MXene (Ti3C2) is a two-dimensional material with exceptional electrical conductivity, hydrophilicity, great thermal stability, large interlayer spacing, and a high surface area. Ti3C2'sremarkable characteristics make it well-suited for biomolecule immobilization and target analyte detection. Co3S4is a transition metal chalcogenide that has shown great potential in biosensors. Co3S4 nanoparticles (NPs) can potentially enhance Ti3C2 electrocatalytic activity, particularly in amino acid detection. L-arginine is a semi-essential amino acid, and the body frequently uses it to support healthy circulation and plays a crucial role in protein synthesis. We fabricated the Ti3C2-Co3S4 biosensor for L-arginine detection. Aim This study aims to synthesize and apply Ti3C2-Co3S4 nanocomposites in amino acid biosensing. Materials and methods The Ti3C2 nanosheets were synthesized by the selective removal of an aluminum (Al) layer from the precursor (Ti3AlC2) using hydrofluoric acid (HF). The resulting mixture serves as an etchant, especially targeting the Al layers on Ti3AlC2while protecting the desired MXene layers at room temperature. Cobalt nitrate hexahydrate was dissolved in deionized water. Sodium hydroxide was added to the cobalt solution and stirred. Thioacetamide was added to the above solution and stirred (Solution B). A mixture of Solution A and Solution B was stirred for 30 minutes. The mixture is transferred to a hydrothermal reactor and maintained at a temperature of 180°C for 12 hours. Once the reaction completes, we cool the resultant mixture to room temperature and then filter it using the washing technique. The sample underwent a 12-hour drying process at 80°C. Results This study investigated the use of a biosensor that employed Ti3C2-Co3S4 NPs to detect the concentration of L-arginine. The X-ray diffraction (XRD) shows clear and distinct peaks, which means that the synthesized Ti3C2-Co3S4 nanostructures have a crystalline structure.Scanning electron microscopy (SEM) analysis revealed that the sheetlike structure of synthesized Ti3C2-Co3S4 nanostructuresrevealedthe crystalline morphology. The results of this study show that the Ti3C2-Co3S4NP-based biosensor can be used to detect L-arginine in a sensitive and selective way. Conclusion This study investigated the synthesis of Ti3C2-Co3S4NPs and their ability to detect L-arginine levels and show a distinct correlation between the L-arginine concentration and the fluorescence intensity, demonstrating the biosensor's effectiveness in detecting L-arginine levels.

Influences of Al particles on structure and properties of Ni–Al composite coatings with nanoscale twin structure

Nickel-aluminum (Ni–Al) composite coatings containing nickel nanoscale twins have been prepared by co-electrodeposition on copper substrate. Effects of Al particles on microstructure, chemical composition, friction properties, and corrosion resistance of Ni–Al coatings were investigated. It presents an even and compact structure with granular surface that Al are evenly dispersed in pyramidal-like nickel lattice. Adding Al could alter crystal orientation, refine grains and promote strengthening effects induced by nanoscale twinning. It can enhance anti-corrosion properties and decrease the coefficient of friction (COF). The minimum COF was obtained at 10 g L−1 Al. The larger amounts and even dispersion of Al, the better corrosion resistance and the smaller COF. Increasing Al from 20 to 40 g L−1, incorporated Al in top surface rose from 20.86 to 30.13 wt%, which was larger than in cross section from 13.93 to 18.86 wt%. As the incorporated depth increased, the particle color changed from grey to dark. Nano-twins were generated around enveloped Al particles. The roughness increased as Al rose from 10 to 40 g L−1. The average roughness (Ra) was of 191–231 nm. Ni–Al-5g and Ni–Al-80g have excellent anti-corrosion features, owning the maximum Rct of 1437.2 and 1565.1 kΩ cm2, respectively, associated with the amount and distribution of Al particles, preferred orientation, grain sizes, and twinned structure. The enhanced corrosion resistance might be due to the generation of uniform, compact aluminum oxide layer by doping Al in nickel.

Impact of Interface Trap Charges on Silicon Carbide (4H-SiC) Based Gate – Stack, Dual Metal, Surrounding Gate, FET (4H-SiC- GSDM-SGFET) for Analog and Noise Performance Analysis for 5 G/LTE Applications

This article examines the impact of various interface trap charges on silicon carbide-based gate—stack, dual metal, surrounding gate, FET (4H-SiC-GSDM-SGFET). It has been contrasted for performance with silicon carbide (4H-SiC)-based dual metal, surrounding gate, FET (4H-SiC-DM- SGFET). For both devices, output characteristics including transconductance (gm), output conductance (gd), drain current (Ids), gate capacitance (Cgg), cutoff frequency (fT) and threshold voltage (Vth) have been examined. Surface potential and electron concentration were also inspected using a contour plot for both the device structures. A gate-stack with a high k- dielectric, Lanthanum oxide (La2O3) along with gate dielectric layer Aluminum oxide (Al2O3) was used for proposed structure implementation. Additionally, we investigated how trap charges affect noise figure (NF) and noise conductance (NC). Also, a CMOS inverter has been developed and its output characteristics have been compared for both the device architectures. ATLAS 3-D device simulator has been employed to conduct the simulations.

Influence of additional intermediate thick Al layers on the reaction propagation and heat flow of Al/Ni reactive multilayers

This study investigates the effects of sputtering and electron beam evaporation (e‐beam) on the microstructure and reactive properties of Al/Ni reactive multilayers (RML). The intermixing zone, a critical factor influencing reaction kinetics, was characterized using high‐resolution transmission electron microscopy and found to be consistently 3 nm for both fabrication methods. Differential scanning calorimetry revealed that e‐beam samples, with thicker Al layers, exhibited slightly higher total molar enthalpy and maintained high reaction temperatures despite reduced reaction velocities in comparison to sputtered samples. X‐ray diffraction confirmed the formation of both Al3Ni2 and AlNi phases in the e‐beam samples. These findings indicate that while thicker bilayer structures reduce reaction velocity, they keep thermal output and mitigate the impact of intermixing zones, leading to similar total molar enthalpy. This analysis underscores the significance of deposition technique and bilayer thickness in optimizing the performance of Al/Ni RML, offering the possibility to establish different phase formations in thicker RML. It advances the control over the reactive properties of reactive multilayers in their applications, for example reactive bonding.This article is protected by copyright. All rights reserved.

Study on Newer Techniques of TIG Welding and Microstructure of Welded Parts of Aluminium Composites and Alloys: A Review

Over the years, alloys and metal matix composites (MMC) has developed into an essential material for modern manufacturing processes. Especially, aluminium based MMCs have a widespread importance due to their physical and chemical properties making them applicable for aviation and aerospace industries. Also, lightness and high strength-to-weight ratio are two important factors for their widespread usage. Manufacturing in these industries involve joining processes, wherein welding plays primary role. In welding of aluminium, Tungsten Inert Gas (TIG) welding process is highly preferred. Although, aluminium welding confronts a major problem due to formation of alumina (Al2O3), however this is overcome due to usage of pulsed TIG welding. In this process, one half of the pulse breaks the alumina layer to aid in welding. This paper investigates various modern techniques of welding aluminium alloys and metal matrix composites. Also, the findings regarding microstructure and mechanical properties of the welded parts are studied. Key Words: Aluminium, Welding, Tungsten Inert Gas welding, Microstructure, Mechanical properties.

Investigating the effect of O2 plasma treatment on the operational characteristics of Schottky-gate AlGaN/GaN HEMT

This study investigates the effect of O2 plasma treatment on the physical and electrical properties of the surface region in Schottky-gate AlGaN/GaN high electron mobility transistor (HEMT). We demonstrate that O2 plasma treatment significantly reduces the gate leakage current and enhances the on/off ratio by three orders of magnitude compared to devices without treatment. The O2 plasma treatment removes organic chemical residue and forms Ga–O bonds on the AlGaN surface beneath the gate metal. X-ray photoelectron spectroscopy results indicate that the treatment effectively forms a Ga–O compound oxide layer, which provides surface passivation. Furthermore, atomic force microscope analysis reveals a 50% reduction in surface roughness after the O2 plasma treatment. Using O2 plasma oxidation treatment caused a shift in the threshold voltage (VTH ) of Schottky-gate AlGaN/GaN HEMT. Initially measured at −5.26 V, the VTH value shifted to +0.5 V. Furthermore, we also employ TCAD simulation to assist in the process developed during the manufacturing process. It is worth noting that the drain current decreases as the Ga–O compound oxide layer increases. This is due to effectively depleted the polarization charges at the AlGaN/GaN interfaces during E-mode operation when reducing the thickness of the AlGaN layer beneath the gate metal. Our results demonstrate the importance of O2 plasma surface treatment in achieving optimal device performance. This study systematically discusses the effect of O2 plasma on AlGaN/GaN surface properties and the formation of Ga–O bonding. It offers insights into developing high-performance Schottky-gate AlGaN/GaN HEMT.

Catalytic Activity Evaluation of Molten Salt-Treated Stainless Steel Electrodes for Hydrogen Evolution Reaction in Alkaline Medium

The goal of this research is to fabricate a novel type of highly active porous electrode material, based on stainless steel and dedicated to water electrolyzers. The main novelty of the presented work is the innovative application of the molten salts treatment, which allows the design of a highly developed porous structure, which characterizes significantly higher catalytic activity than untreated steel substrates. The equimolar mixture of NaCl and KCl with 3.5 mol% AlF3 was used as the molten salt. The surface modification procedure includes the deposition of an Al layer with application at the potential of −1.8 V and following dissolution at −0.9 V, to create a porous alloy surface. The cathodic polarization measurements of the prepared porous stainless steel electrodes were measured in a 10 mass% KOH solution. Moreover, the amount of hydrogen generated during constant voltage electrolysis with a hydrogen sensor in situ was also measured. The porous stainless steel alloy showed higher current density at lower potentials in the cathodic polarization compared to untreated stainless steel. The cathodic polarization measurements in alkaline solution showed that the porous 304 stainless steel alloy is an excellent cathode material.

Formation of Anti-Reflection Coatings Based on Nanostructured Aluminum and Barium Titanate Xerogel Layer

The research has been carried out on the formation of anti-reflection coatings based on porous aluminum obtained by electrochemical anodic etching and a layer of barium titanate xerogel deposited on its surface. The thickness of the porous aluminum ranged from 15 to 100 microns. Analysis of the reflection spectra of the resulting structures showed effective anti-reflection properties of the formed coatings with a specular reflection coefficient of 0.25–2.50 % in the range of 200–1100 nm. The use of formed coatings with a low reflectance coefficient is possible in aircraft manufacturing, electronics and energy.