Carbide Nitride Research Articles

Possible formation of H2 hydrates in different nanotubes and surfaces using molecular dynamics simulation.

In this work, we simulated water molecules confined in carbon, boron nitride (BN), and silicon carbide (SiC) nanotubes with similar sizes. We also simulated water molecules confined between parallel graphene, BN, and SiC surfaces in two cases: (a) a similar geometric surface density of water of 0.177/Å2, in which the number of gas molecules was 18% of the total water molecules, and (b) a similar density profile of water of 0.04-0.05 dalton per Å3. To examine H2 hydrate formation, we added guest H2 molecules to the confined water molecules in the nanotube and surface systems. We analyzed the formed shapes, adsorption energies, radial distribution functions (RDFs), and self-diffusion coefficients of the confined molecules in gas hydrate formation. Our results showed that a more ordered heptagonal ice nanotube was formed in the BN nanotube than that in the other systems. After the addition of H2 molecules in the different nanotubes, some of the H2 molecules occupied the wall of the ice nanotube and some of them positioned in the hollow space. Although gas hydrates were created in all surface systems, ordered gas hydrate shapes were formed only in the graphene system. The adsorption energy for guest H2 molecules between the different surfaces was negative, which means that the formation of H2 hydrates between these surfaces is a spontaneous process (unlike that in the nanotube systems). According to RDF results, the BN nanotube and graphene surfaces are proper systems to form more ordered H2 hydrate structures. The confined water molecules have much higher diffusion coefficients in the BN nanotube and graphene surfaces than in the other systems. The F 4 parameter also substantiated hydrate formation in the different nanostructures. In a new configuration of BN and SiC systems with density profiles similar to that of the graphene system, the H2 hydrate was not formed completely as in the case of the graphene system. H2 hydrates formed in the new BN and SiC surfaces were less than those formed in the primary structures (with a geometrical density similar to that of the graphene system) and the graphene system.

Printed High-Adhesion Flexible Electrodes Based on an Interlocking Structure for Self-Powered Intelligent Movement Monitoring.

Two-dimensional transition metal carbide nitrides (MXenes) have been extensively explored in diverse areas, such as electrochemical energy storage and flexible electronics. Although the solution-processed MXene-based device has made significant achievements, it is still a challenge to develop large-scale and high-resolution printing methods for flexible printed electronics. In this work, we reported a novel strategy of a porous interlocking structure to obtain flexible MXene/laser-induced graphene (LMX) composite electrodes with enhanced adhesion and high printing resolution. In comparison to traditional printed MXene electrodes, the LMX electrode with an interlocking interface possesses enhanced mechanical properties (adhesive strength of 2.17 MPa) and comparable electrical properties (0.68 S/mm). Furthermore, owing to the outstanding stability and flexibility, the LMX-based triboelectric nanogenerator (TENG) can be used as a self-powered sensor to monitor finger-bending movement. A support vector machine (SVM)-assisted self-powered motion sensor can distinguish the bending angle with high recognition accuracy and can effectively identify different angles. The successful experience of directly printing flexible electrodes with excellent mechanical and electrical properties can be promoted to other solution-processed two-dimensional materials. Our strategy opens up a promising perspective to develop flexible and printed electronics.

A Comprehensive Investigation of BN and VC Reinforcements on the Properties of FSP AA6061 Composites

This present study investigated the impact of incorporating boron nitride (BN) and vanadium carbide (VC) reinforcements on various properties of friction stir processed (FSP) AA6061 alloy composites, focusing specifically on grain structure, thermal conductivity, electrical conductivity, and compressive strength. The findings indicate that VC more effectively refines the grain structure of the AA6061 alloy during FSP compared to BN. The inclusion of BN particles in the metal matrix composites resulted in a decrease in both thermal and electrical conductivity. In contrast, the addition of VC particles led to an increase in both thermal and electrical conductivity. The AA6061/VC composite material exhibited the highest thermal conductivity among all composites tested. The electrical conductivity of the hybrid-composite AA6061/30%BN+70%VC showed a slight reduction, measuring only 2.8% lower than the base alloy AA6061. The mono-composite AA6061/VC exhibited a marginal decrease in thermal conductivity, with a measured value only 7.5% lower than the conventional alloy AA6061. However, the mono-composite AA6061/BN displayed a more significant decline, exhibiting a loss of 14.7% and 13.9% in electrical and thermal conductivity, respectively. The composite material comprising 30% BN and 70% VC reinforcement demonstrated the highest compressive strength compared to all other tested composites. The observed percentage enhancement in the mechanical properties of mono and hybrid composites, compared to the parent AA6061 alloy, ranged from 17.1% to 31.5%.

Degradation and power generation performance of modified-anode microbial fuel cells for kitchen wastewater

Microbial fuel cells (MFCs) are innovative devices that simultaneously generate electricity and treat wastewater. The performance of MFCs heavily relies on the anode, which serves as the site for the enrichment, electron generation, and transfer of electricity-producing microorganisms. In this study, Researcher investigated the impact of modified electrode materials (Fe3N-Fe3C/CF) loaded with iron nitride and iron carbide nanoparticles at different temperatures on MFC performance, employing carbon felts as anodes. Our results reveal a significant enhancement in the electrical performance of the modified carbon felt anode compared to conventional carbon felt. Notably, when the modified electrode was prepared at 850 °C, the output voltage of the microbial fuel cell assembled with the modified electrode was significantly increased, and its maximum power density increased from 28.57 MW m−2 to 58.86 MW m−2. These findings highlight the potential of high-performance anode materials, as demonstrated in this study, to serve as a reference for enhancing MFC performance.

Susceptor based design strategies for enhancing microwave hybrid heating capability via experimental analysis, 3D multi-physics simulation and parametric optimization

Microwave processing has gained remarkable recognition based upon volumetric processing that is energy efficient. Susceptor-assisted microwave heating is a fast-emerging technology because of its advantages over traditional microwave processing. Susceptor help to speed up microwave processing by offering two-way heating with less heat loss from the material's surface. The present investigation brings out ways (theoretical, simulation and experimental) to select appropriate susceptor material by considering different types of microwaves absorbing material (alumina, yttria stabilized zirconia, boron nitride and silicon carbide) for efficient microwave heating. Theoretical analysis (dielectric properties, penetration depth, absorption loss and reflection loss) suggests silicon carbide (SiC) to be the most suitable susceptor. COMSOL Multiphysics based simulation in conjunction with experimental results were utilized for critical understanding of SiC susceptor heating. The influence of physical parameters: microwave input power, microwave frequency, placement of susceptor inside cavity and dimension of susceptor on electric field distribution and temperature profile of SiC susceptor are also investigated and presented in detail. Among all susceptor materials, SiC exhibited highest heating rate in similar operating parameters. The temperature obtained for SiC susceptor during microwave heating without casket (80 °C) was significantly lower than that with casket insulation (1003 °C). A susceptor of 10 mm thickness with cross-section of 625 mm2 was found to be the optimum dimension for SiC susceptor. The maximum temperature obtained by the SiC susceptor was 658 °C, 1003 °C, 1182 °C and 1380 °C for input power of 800 W, 1200 W, 1600 W and 2000 W respectively. Simulation data were validated with experimental results. The results exhibit a good agreement between simulation results and experimental data.

Impact of boron nitride and silicon carbide on tribological properties of Al-3Gr-based hybrid composites

Impact of boron nitride and silicon carbide on tribological properties of Al-3Gr-based hybrid composites

Boron containing polyvinyl alcohol/ polyethylene oxide/polyvinyl pyrrolidone composites: Preparation, characterization, gamma radiation shielding and gamma radiation effect on it's thermal properties

The production of PVA/PEO/PVP-B4C and PVA/PEO/PVP-BN nanocomposites is presented in this study by adding certain proportions of boron nitride (BN) and boron carbide (B4C) to the polyvinyl alcohol(PVA)/polyethylene Oxide (PEO)/polyvinyl pyrrolidone (PVP) blend. The percentages of BN and B4C nano powder in the PVA/PEO/PVP blend have been determined as 5%, 10% and 20%. Thermal characterizations were carried out with different techniques such as Differential scanning calorimetry (DSC), Differential Thermal Analysis (DTA), Thermogravimetry (TG). Surface, crystal structure and atomic percentage distribution analyzes of the obtained composites were performed by X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction Analysis (XRD), Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), and elemental analysis. 10 kGy gamma irradiation was performed on PVA/PEO/PVP-B4C and PVA/PEO/PVP-BN composites. The thermal behavior of the composites at this dose level was investigated. In addition, the radiation shielding properties of composite films obtained at 10 cm distances using Am-241 beam source were examined.

Bias-assisted photoelectrochemical planarization of GaN (0001) with impurity concentration distribution

To planarize semiconductor materials such as gallium nitride (GaN) and silicon carbide with high efficiency, we developed a polarization method that combines ultraviolet irradiation and an abrasive-free polishing method known as catalyst-referred etching (CARE). In this method, the substrate surface is photoelectrochemically oxidized, thus improving the removal rate. Accordingly, an atomically well-ordered surface was obtained at a removal rate 100 times higher than that of the conventional CARE method without ultraviolet irradiation. However, in some cases, for GaN substrates with a high oxygen impurity concentration area, the oxidation rate is nonuniform on the substrate surface, resulting in the formation of a rough surface. In this study, we propose the application of a positive bias to the GaN substrate to suppress the oxidation rate fluctuation. In the positive bias state, the width of the depletion layer generated at the interface of GaN and the etchant becomes uniform on the entire surface regardless of crystallographic fluctuation, thereby achieving a uniform oxidation rate. When only 3.0 V was applied, the oxidation rate was uniform; thus, a flat GaN surface without the footprint originating from crystallographic fluctuations was obtained.

Power Module Design for GaN Transistors Enabling High Switching Speed in Multi‐Kilowatt Applications

The advantages of gallium nitride and silicon carbide transistors over silicon devices are highlighted. The design criteria for power modules in multi‐kilowatt applications to effectively leverage these advantages are described. Various concepts to overcome limitations associated with state‐of‐the‐art power module packaging presented in the literature are summarized and evaluated. A novel power module design comprising a 650 V, 300 A half‐bridge with integrated direct current–link and gate drivers is proposed. The results of a finite‐element analysis of its parasitic elements and subsequent double‐pulse test simulation are presented.

Crystallographic Study of Product Phases of Carbothermic Reduction and Nitridation of Hafnium Dioxide.

Details of the carbothermic reduction/nitridation to synthesize hafnium nitride (HfN) and hafnium carbide (HfC) are scarce in the literature. Therefore, this current study was carried out to evaluate two pathways for synthesizing these two refractory materials: direct nitridation and carbothermic reduction/nitridation. Two mixtures of hafnium dioxide and carbon with C/HfO2 molar ratios of 2.15 and 3.1 were nitridized directly using flowing nitrogen gas at elevated temperatures (1300-1700 °C). The 3.1 C/HfO2 molar ratio mixture was also carbothermically reduced under flowing argon gas to synthesize HfC, which was converted into HfN by introducing a nitridation step under both N2(g) and N2(g)-10% H2(g). X-ray diffraction results showed the formation of HfN at 1300 and 1400 °C and HfC1-yNy at ≥1400 °C under direct nitridation of samples using a C/HfO2 molar ratio of 2.15. These phase analysis data together with lower lattice strain and greater crystallite sizes of HfC1-yNy that formed at higher temperatures suggested that the HfC1-yNy phase is preferred over HfN at those temperatures. Carbothermic reduction of 3.1 C/HfO2 molar ratio samples under an inert atmosphere produced single-phased HfC with no significant levels of dissolved oxygen. Carbothermic reduction nitridation made two phases of different carbon levels (HfC1-yNy and HfC1-y'Ny', where y' < y), while direct nitridation produced a single HfC1-yNy phase under both N2 and N2-10% H2 cover gas environments.

Machinability Measurements in Milling and Recurrence Analysis of Thin-Walled Elements Made of Polymer Composites

The milling of polymer composites is a process that ensures dimensional and shape accuracy and appropriate surface quality. The shaping of thin-walled elements is a challenge owing to their deformation. This article presents the results of milling polymer composites made of glass and carbon fibers saturated with epoxy resin. The milling of each material was conducted using different tools (tools with polycrystalline diamond inserts, physically coated carbide inserts with titanium nitride and uncoated carbide inserts) to show differences in feed force and deformation after the machining of individual thin-walled samples. In addition, the study used recurrence analysis to determine the most appropriate quantifications sensitive to changes occurring in milling different materials with the use of different tools. The study showed that the highest forces occurred in milling thin-walled carbon-fiber-reinforced plastics using uncoated tools and the highest feeds per revolution and cutting speeds. The use of a high feed per revolution (0.8 mm/rev) in carbon-fiber-reinforced plastics machining by uncoated tools resulted in a maximum feed force of 1185 N. A cutting speed of 400 m/min resulted in a force of 754 N. The largest permanent deformation occurred in the milling of glass-fiber-reinforced composite samples with uncoated tools. The permanent deformation value of this material was 0.88 mm. Low feed per revolution (0.1 mm/rev) resulted in permanent deformations of less than 0.30 mm for both types of materials. A change in feed per revolution had the most significant effect on the deformations of thin-walled polymer composites. The analysis of forces and deformation made it possible to conclude that high feed per revolution were not recommended in composite milling. In addition to the analysis of machining thin-walled composites, the novelty of this study was also the use of recurrence methods. Recurrence methods were used to determine the most appropriate quantifications. Determinism, averaged diagonal length and entropy have been shown to be suitable quantifications for determining the type of machined material and the tools used.

Multiphoton Absorption in Gallium Nitride and Silicon Carbide Photodiodes: Applications for Single-Event Effects Tests

We report on the investigation of multiphoton absorption processes in gallium nitride and silicon carbide photodiodes. Up to three-photon absorption mechanisms were evidenced on both materials, thanks to a wavelength-tunable femtosecond laser chain. These results are applied to single event effect investigations on a commercial gallium nitride high electron mobility transistor. We could trigger single event transients by focusing the beam throughout the silicon substrate and collect charge that was photogenerated in the gallium nitride layer by a three-photon absorption process.

The effect of boron nitride (h-BN) and silicon carbide (SiC) on the microstructure and wear behavior of ZA40/SiC/h-BN hybrid composites processed by hot pressing

The effect of boron nitride (h-BN) and silicon carbide (SiC) on the microstructure and wear behavior of ZA40/SiC/h-BN hybrid composites processed by hot pressing

Enhancing Thermal Conductivity of hBN/SiC/PTFE Composites with Low Dielectric Properties via Pulse Vibration Molding.

In order to enhance the thermal conductivity of polytetrafluoroethylene (PTFE)-based composites, while maintaining relatively low dielectric constant and dielectric loss for high-frequency and high-speed applications, hexagonal boron nitride (hBN) and silicon carbide (SiC) compounded fillers are filled into the PTFE matrix. The hBN/SiC/PTFE composites are prepared by pulse vibration molding (PVM), and their subsequent thermal conductivities are comparatively investigated. The PVM process with controlled fluctuation in pressure (1Hz square wave force, 0-20MPa, at 150°C) can reduce the sample porosity and surface defects, improve the orientation of hBN, and increase the thermal conductivity by 44.6% compared with that obtained by compression molding. When hBN:SiC (vol) is 3:1, the in-plane thermal conductivity of the composite with 40vol% filler content is ≈4.83Wm-1 K-1 , which is 40.3% higher than that of hBN/PTFE. Regarding the dielectric properties, hBN/SiC/PTFE maintains a low dielectric constant of 3.27 and a low dielectric loss of 0.0058. The dielectric constants of hBN/SiC/PTFE ternary composites are predicted by using different prediction models, among which the effective medium theory (EMT), is in good agreement with the experimental results. PVM shows great potential in the large-scale preparation of thermal conductive composites for high-frequency and high-speed applications.

Effect of Microstructure on Mechanical Behaviors of Al6061 Metal Matrix Composite Reinforced with Silicon Nitride (Si3N4) and Silicon Carbide (SiC) Micro Particles

Effect of Microstructure on Mechanical Behaviors of Al6061 Metal Matrix Composite Reinforced with Silicon Nitride (Si3N4) and Silicon Carbide (SiC) Micro Particles

Recent Advances and Perspectives on Supported Catalysts for Heterogeneous Hydrogen Production from Ammonia Borane.

Ammonia borane (AB), a liquid hydrogen storage material, has attracted increasing attention for hydrogen utilization because of its high hydrogen content. However, the slow kinetics of AB hydrolysis and the indefinite catalytic mechanism remain significant problems for its large-scale practical application. Thus, the development of efficient AB hydrolysis catalysts and the determination of their catalytic mechanisms are significant and urgent. A summary of the preparation process and structural characteristics of various supported catalysts is presented in this paper, including graphite, metal-organic frameworks (MOFs), metal oxides, carbon nitride (CN), molybdenum carbide (MoC), carbon nanotubes (CNTs), boron nitride (h-BN), zeolites, carbon dots (CDs), and metal carbide and nitride (MXene). In addition, the relationship between the electronic structure and catalytic performance is discussed to ascertain the actual active sites in the catalytic process. The mechanism of AB hydrolysis catalysis is systematically discussed, and possible catalytic paths are summarized to provide theoretical considerations for the designing of efficient AB hydrolysis catalysts. Furthermore, three methods for stimulating AB from dehydrogenation by-products and the design of possible hydrogen product-regeneration systems are summarized. Finally, the remaining challenges and future research directions for the effective development of AB catalysts are discussed.

Reinforcement philosophy and effect of nano sized materials on mechanical, corrosive and wear behaviour of magnesium nanocomposites- a critical review

The present study focuses on current developments in the area of nanoparticles reinforced magnesium (Mg) based composites. Recently, nano sizedreinforced magnesium metal matrix composites are gaining importance in high performance applications like military, automotive and aerospace industries as a result of their improved physical and mechanical properties.Because desired performance is critical to achieve in micron sized magnesium composites due to their poor ductility, wear and friction response. Researchers find one technique to improve these properties, without any tangible weight penalty of magnesium and its alloys is to add nano size (<100 nm) reinforcement particles to the matrix as create so-called magnesium nanocomposites. Different nano reinforcing materialssuch asCarbon nanotubes (CNTs), Graphene (GNPs),Graphite (Gr), Silicon Nitride (Si3N4), Aluminium Oxide (Al2O3), Boron Nitride (hBNp), Diamond (ND), Titanium Carbide (TiC) and Tungsten Carbide (WC) have been studied. Moreover; the consequence of nano size particles on physical, microstructural, mechanical, corrosive and dry sliding wear properties of magnesium and its composites have been briefly discussed. The future research directions and development on current research area have been discussed and reviewed.

Novel V-BiOIO3/g-C3N4/WC Schottky heterojunction with optimizing optical absorption and charge transfer for abatement of tetracycline antibiotics

A novel Schottky heterojunction was obtained by co-calcining fish-scale tubular carbon nitride (FTCN), V-BiOIO3 and Tungsten carbide (WC) for photocatalytic degradation of tetracycline hydrochloride (TCH). The novel Schottky heterojunction has been analyzed by several characterizations and experiments. The case of photocatalytic degradation was studied for different initial concentrations, electrolyte and pH, respectively. The experiments have indicated that the V-BiOIO3/g-C3N4/WC performed an excellent activity of photocatalytic for TCH degradation (89.0%). In the mechanism analysis, we first deduce that the V-BiO3/FTCN compound belongs to the S-scheme heterojunction photocatalysts based on the properties of the band gap structure, which can effectively suppress recombination of joint carriers. Secondly, the introduction of the cocatalyst WC formed Schottky junction, which could play a role as an electronic library to trap e− and promote the separation of photo-induced carrier and thus maximize the strong oxidation ability of h+. In addition, the introduction of WC could also significantly enhance the optical absorption properties of the composites. This research could provide a new idea for the construction of novel and efficient carbon nitride-based photocatalysts under VSL (visible light), and promote its practical application in environmental remediation.

Influence of hybrid nanofluid on tool wear and surface roughness in MQL-assisted face milling of AISI 52100

ABSTRACT With escalating demand for machinability, economical production, health, and environment-related aspects are pushing the present industrial units to drop the usage of harmful-cutting fluid in machining. However, the adaption of this approach for machining difficult-to-cut materials does not ensure favourable outcomes of the tool performance, surface qualities, etc., as friction and heat seriously disturb machining efficiency. This study is focused on near-dry machining employing recently developed hybrid nanofluids-based lubrication in the machining of AISI 52,100 steel. Hexagonal boron nitride (hBN) and silicon carbide (SiC) nanoparticles are added to the lubrication oil to enhance the performance of the Minimum Quantity Lubrication (MQL) system. Taguchi’s method-based Grey relational analysis (GRA) is used for the concurrent optimisation of the tool flank wear and surface roughness. The best parametric setting for the multi-response is achieved as: a lubricant flow rate of 150 ml/h, depth of cut of 0.2 mm, and nanofluid with 0.8 wt % of hBN and 0.2 wt % of SiC nanoparticles. The confirmation experimentation concluded that the multi-response factor is enhanced by 2.48% at the optimum setting with the mean values of TFW and SR as 84 and 0.36 µm, respectively.

Influence of Microstructure on Tribological Behaviors of Al6061 Metal Matrix Composite Reinforced with Silicon Nitride (Si3N4) and Silicon Carbide (SiC) Micro Particles

Dual step stir casting method was utilized to develop Al6061 composite reinforced with SiC (micron) and Si3N4 (submicron) particles in varying proportion and weight percentage. A homogeneous and uniform distribution of hybrid reinforcement without significant porosity was observed in the microstructure of the composites. X-ray diffraction (XRD) results manifest that Si3N4 and SiC particles are thermodynamically stable during the processing and no unwanted phases were detected. Elemental mapping was also performed for phase identification. With reference to the base alloy significant improvement was noticed in physical and tribological properties of hybrid composites. Maximum rise in hardness was 54.64%. Abrasive wear test results from pin on disc reveals that wear resistance get enhanced for all composition and load is found to be most dominating factor affecting wear behavior.