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With more than thirty years of research and development until commercialization, performance, reliability, and robustness of silicon carbide (SiC) based devices have been improved significantly due to drastic reduction in crystal defects from the well-controlled processes of crystal growth and device fabrication. It is crucial to investigate the effects of SiC crystal defects on the electrical characteristics of devices. Here, an up-to-date development of the correlation between crystal defects of SiC with electrical performance of the devices has been reviewed. The effect of defects on the electrical parameters of the device and the failure mechanism are discussed, and the development of SiC in recent years is prospected. [ABSTRACT FROM AUTHOR]

The possibility of using axial spin centers with S = 3 / 2 in silicon carbide for all-optical measurement of the projection B z of the external magnetic field onto the c -axis of the SiC crystal, as well as the polar and azimuthal angles of the magnetic field relative to the direction of the c -axis, at room and significantly higher temperatures is shown. Spin centers in SiC, where optically induced spin alignment occurs, have a unique system of spin levels in a magnetic field, caused by the interaction of the fine structure and hyperfine interaction with the 29 Si nuclei. There is a wide range of level anticrossings (LACs) resulting in an extremely strong change in the photoluminescence intensity at LAC. The dependence of the LAC spectrum on the orientation of the external magnetic field is also observed. The proposed magnetometer is based on the compensation of the external magnetic field at the position of the optical excitation spot of the confocal microscope. The sensitivity to a constant magnetic field for the z-component of the magnetic field (B z) is better than 0.1 μ T / Hz in the confocal volume at room temperature. The sensitivity of polar and azimuthal angle determination depends on the sensitivity of the perpendicular component of the magnetic field, which is better than ∼ 0.01 mT / Hz in the range from − 0.4 to 0.4 mT. [ABSTRACT FROM AUTHOR]

Silicon carbide and its derivatives are promising materials with potential applications in various types of nuclear reactors. To better understand their characteristics, this paper investigates the recrystallization behavior of amorphous SiC prepared through pre-irradiation using 800 keV Kr2+. Following different annealing processes, Raman spectra revealed that recrystallization happened beyond 873 K, and nearly complete recrystallization of the amorphous layer occurs at 1423 K. Afterward, in situ annealing and He+ irradiation experiments were conducted. The results indicate that the recrystallization progress is a layer-by-layer epitaxial regrowth on the amorphous–crystal interface under 873 K annealing, and the epitaxial recrystallization would slow down mainly due to the accumulation of defects and Kr atoms. However, under 30 keV He+ irradiation at 873 K, the interface continues to move. Moreover, when the irradiation dose rises, nanocrystals and helium bubbles appear simultaneously, growing in both size and density. The different recrystallization behaviors caused by irradiation and non-irradiation conditions could be explained by radiation-enhanced atomic diffusion, and helium bubbles are likely to be the by-products of nanocrystal formation. A possible explanation is proposed. This study provides insights into the practical application of amorphous silicon carbide in reactors and other irradiation environments. [ABSTRACT FROM AUTHOR]

Silicon/carbon (Si/C) nanocomposites are considered as one of the most promising anode materials for lithium-ion batteries due to their high capacity and suitable lithiation potential. However, the complex and time-consuming preparation processes of silicon-based nanocomposites and the unexpected silicon carbide generated during high treatment make it difficult to achieve high-performance Si/C nanocomposites for practical applications. Herein, a silicon/carbon nanocomposite is successfully prepared through a facile and eco-friendly molten salt assisted precarbonization–reduction method using palygorskite (PAL) and sodium alginate as raw materials. Based on physical characterizations, it is demonstrated that the sodium alginate plays a key role in the successful preparation of Si/C nanocomposite, which not only boosts uniform embedding of PAL nanoparticles in the carbon matrix but also releases molten sodium salt to suppress the formation of unexpected SiC. When used as an alternative anode material for lithium-ion battery applications, the as-obtained Si/C composite delivers a high reversible specific capacity of 1362.7 mA h g−1 with an initial Coulombic efficiency of 70.3% at a current density of 200 mA g−1 and excellent long-term cycling stability. The findings here provide a facile and eco-friendly molten salt assisted precarbonization–reduction method for high-performance silicon/carbon anode materials. [ABSTRACT FROM AUTHOR]

Point defect color centers acting as single-photon emitters are promising for quantum technology applications and have been extensively studied, e.g., in the 4H polytype of silicon carbide (SiC). However, the physics of such color centers in other SiC polytypes is much less explored. Herein, we study the formation and thermal stability of such color centers in 6H-SiC using photoluminescence spectroscopy. The emissions from typical single-photon emitters, such as silicon vacancies, divacancies, and carbon antisite-vacancy pairs in 6H-SiC, were monitored as a function of the proton irradiation fluence and post-irradiation annealing, and compared to that in 4H-SiC. Overall, at the background of similarities between the emission behavior in 4H- and 6H-SiC polytypes, we observed prominent differences; e.g., for the thermal stability of the carbon antisite-vacancy pair, which exhibited maximized emissions upon 300 and 900 ° C anneals in 4H- and 6H-SiC, respectively. Moreover, we observed a range of defect emission signatures not previously reported for 6H-SiC in the literature and discussed their potential origin in the context of the thermal stability. For example, among the PL-lines in 6H-SiC, we detected periodically repeatable emission signatures, resembling the so-called L-lines recently reported in 4H-SiC, even though their exact origin has not yet been settled in the literature. Thus, we use color centers comparison in different polytypes to better understand the nature of the single-photon emitters in SiC. [ABSTRACT FROM AUTHOR]

4H Silicon carbide (SiC) is widely recognized as one of the most advanced wide bandgap semiconductors used in the production of high-efficiency power electronic devices. Impurities play a crucial role in achieving the desired electrical properties in 4H-SiC, yet the understanding of impurities in this material remains limited. In this study, first-principles formation-energy calculations were employed to establish a comprehensive database of formation-energy diagrams for impurities in 4H-SiC. This database includes valuable information on site preference, lattice distortion, solubility, and charge transition levels (CTLs) of the impurities. The site preference for each impurity is closely related to factors such as the Fermi energy, chemical potential, and the impurity species itself. To assess the lattice distortion caused by each impurity, a comparison was made between the volume changes before and after doping. Moreover, the solubility of each impurity was determined using the detailed balance theory, thereby enabling a direct measure of the maximum impurity concentration achievable in the material. Based on the CTLs, the impurities in 4H-SiC were classified into four categories: n-type impurities, p-type impurities, amphoteric impurities, and non-electroactive impurities. This comprehensive property database for impurities in 4H-SiC provides valuable insights for tailoring the material properties through controlled doping, thereby ultimately leading to enhanced performance of power electronic devices. [ABSTRACT FROM AUTHOR]

4H Silicon carbide (4H-SiC) is widely recognized as a highly promising material for high-voltage and high-power electronic applications due to its exceptional properties. The performance of devices based on 4H-SiC is often weakened by the presence of carbon-related point defects, particularly carbon vacancies (VC). The defects of VC introduce deep-level traps (e.g., Z1/2 and EH6/7) that deteriorate device functionality. Experimental and theoretical studies on VC have led to some conflicting results about the charge states of VC, especially for the charge state ordering of EH6/7. We now employ ab initio metadynamics (META) to systematically investigate configuration space including the direction and magnitude of bond distortion and identify the most stable structures of VC. Eventually, the charge states of VC in 4H-SiC are identified. The Z1 (EH6) and Z2 (EH7) indicate transitions from acceptor (donor) levels of VC, located on the h and k sublattice sites, respectively. Z1 and Z2 demonstrate negative-U ordering, characterized by U values of −0.16 and −0.37 eV, respectively. Conversely, EH6 and EH7 display positive-U ordering, with U values of 0.16 and 0.08 eV, respectively. The current results provide insights into the properties of VC in 4H-SiC, highlighting the effectiveness of META in the exploration of complex potential energy surfaces associated with point defects in solids. [ABSTRACT FROM AUTHOR]

Based on the transport and polarization relaxation theories, the effects of hydrogen, fluorine, and chlorine atom passivation on the conductivity and dielectric properties of silicon carbide nanowires (SiCNWs) were numerically simulated. The results show that passivation can decrease the dark conductivity of SiCNWs and increase its ultraviolet photoconductivity. Among them, the photoconductivity of univalent (H) passivated SiCNWs is better than that of seven-valent (Cl, F) passivated SiCNWs. In terms of dielectric properties, the passivated SiCNWs exhibit a strong dielectric response in both deep ultraviolet and microwave regions. Hydrogen passivation SiCNWs produce the strongest dielectric response in deep ultraviolet, while fluorine passivation SiCNWs produce the strongest dielectric relaxation in the microwave band, which indicates that atomic passivation SiCNWs have a wide range of applications in ultraviolet optoelectronic devices and microwave absorption and shielding. [ABSTRACT FROM AUTHOR]

The article "Biorestorative Modification of White Spot Lesions in Anterior Teeth" explores the causes, diagnosis, and treatment of white spot lesions (WSLs) in teeth, particularly in relation to orthodontic therapy. It discusses various treatment options, including enamel microabrasion, resin infiltration, and bleaching, to address WSLs effectively. The article emphasizes the importance of patient involvement in prevention, management, and treatment decisions, highlighting the need for conservative and minimally invasive approaches to restore tooth aesthetics and function. [Extracted from the article]

Oxide‐bonded SiC porous ceramics (SCPCs), synthesized via reaction bonding, exhibit significant potential for high‐temperature applications. However, incorporating sintering aids inevitably results in a considerable quantity of amorphous glass phase within SCPCs, thereby introducing risks to their high‐temperature mechanical performance. In this study, we employ in‐situ characterization techniques to investigate the high‐temperature behavior of SCPCs. Our findings reveal that SCPCs demonstrate remarkable high‐temperature self‐enhancing properties, with a critical bending strength at 800°C. Beyond this temperature, the strength declines sharply. Intriguingly, the critical bending strength is 36.6% greater than at ambient temperature. Moreover, elevated temperatures enhance the elastic modulus and promote the transition of SCPCs from multilinear to nonelastic fracture. The neck phase, which imparts strength to the SCPCs, is composed of four distinct layers along the depth direction: silicate glass, oxygen‐containing, silicon‐rich, and SiC region, as revealed by FIB‐TEM. The transformation from α to β‐cristobalite in the oxygen‐containing region improves the thermal expansion match with SiC, thereby mitigating local stress concentration. Furthermore, the compressive stress within the neck region intensifies with increasing temperatures, thereby inhibiting crack propagation. This work provides a basis for the high‐temperature applications of SCPCs. [ABSTRACT FROM AUTHOR]

Tristructural isotropic (TRISO) fuel particles, developed for use in high‐temperature gas‐cooled nuclear reactors, can be subjected to oxidizing environments in off‐normal accident scenarios. In this study, surrogate TRISO fuel particles were oxidized at 1000–1350°C for 4 h in 20 kPa water vapor atmosphere balanced with ultrahigh‐purity helium gas. The oxide scale morphology and thickness were studied via scanning electron microscopy, focused ion beam, and transmission electron microscopy. The oxide thickness increased as the oxidation temperature was increased. Although the oxide scale at 1000°C was completely amorphous, pockets of crystalline oxide were observed on particles oxidized at 1200 and 1300°C. Kinetic analysis was performed to deduce the oxidation mechanism by determining the apparent activation energy using linear regression analysis. The oxidation mechanism was consistent for temperatures from 1000 to 1200°C with an activation energy of 412.4 ± 8.8 kJ/mol. The activation energy then dropped to approximately 201 ± 7.1 kJ/mol for temperatures 1200–1350°C. Therefore, there is a change in oxidation mechanism at ∼1200°C. This change is attributed to the existence of a network of significant bubbles in the oxide layer at higher temperatures, which serve as rapid diffusion pathways for the transport of oxidants from the surface to the SiC/SiO2 interface, instead of relying on the bulk diffusion through the SiO2 layer at lower temperatures where only small bubbles are present along the SiC/SiO2 interface. [ABSTRACT FROM AUTHOR]

Nickel–tungsten (Ni–W) coatings reinforced with silicon carbide (SiC) were successfully produced on a steel substrate using the pulse electrodeposition method (PED). Influence of SiC addition on phases, crystallite size, dislocation density, residual stress, mechanical properties and corrosion resistance of the coating were investigated. Field emission scanning electron microscopy (FESEM) images revealed a refinement in the coating's surface morphology and distribution of SiC particles. Higher residual stress observed in the as-deposited Ni–W coating was attributed to hydrogen dissolution into the coating, leading to lattice expansion, with the subsequent release of hydrogen, contributing to this stress. Addition of SiC to the Ni–W coating resulted in improvements in hardness and bonding strength by ~23% and ~184%, respectively. Moreover, the addition of SiC to Ni–W coating led to a reduction in the coefficient of friction by about ~34% compared to Ni–W coating. Corrosion properties were evaluated using an immersion test in a 3.5 wt.% NaCl solution. The Ni–W–SiC composite coating exhibited significantly higher corrosion resistance, with ~67% decrease in corrosion rate compared to Ni–W coating. This enhanced corrosion resistance was linked to the grain refinement induced by SiC, which restricted the penetration of corrosive ions onto the substrate. Furthermore, the formation of a continuous barrier layer composed of SiO2, contributed to the improved corrosion resistance. [ABSTRACT FROM AUTHOR]

This research synthesis the aluminium hybrid composite made with 5-15% of nano SiC and 5% of ZrO2 reinforcement via ultrasonic vibration-assisted stir casting techniques. Influences of hybrid reinforcements on tribological behaviour of composites are evaluated by different sliding spans (1000 to 3000m), load (10-20N), and sliding speed (1.5 to 4.5m/s). The hybrid Al5083/5wt% ZrO2/15wt% SiC composite is noted to have a lower wear rate ranging from 0.0008-0.0016 mm3/Nm and enhanced friction coefficient of 12-0.25 at 4.5m/sec for 3000m under 30N applied load. Moreover, the increased sliding speed and distance lead to an increase in the wear rate and limits the friction coefficient. The tribological behaviour of the hybrid composite Al5083/5wt% ZrO2/15wt% SiC was observed to exhibit diverse surface characteristics due to the occurrence of delamination, wear debris, tribo-chemical wear regimes, and two-body and three-body abrasion wear. Furthermore, the presence of pits and oxide layers was also noticed. [ABSTRACT FROM AUTHOR]

The high thermal conductivity of SiC single crystals makes them crucial in fields such as renewable energy and aerospace. Nevertheless, owing to the phonon scattering resulting from crystal boundary, the reported thermal conductivity of SiC ceramic is always well below the intrinsic value. For the SiC ceramic derived from β-SiC (3 C-SiC) starting powder, the β→α phase transformation (i.e. 3 C→4 H) happened imposes significant influences on its microstructure. Therefore, systematic studies of contributions from hetero-/homo- phase boundaries are necessary for understanding the thermal conductivities of resulting SiC ceramic, providing further guidance to the phase transformations control. In this work, the thermal conductivities of both β/β and α/α homophase boundary, as well as β/α heterophase boundary, are systematically investigated. Further, it is found that the highest thermal conductivity is reached at sintering temperature of around 2000 °C, where about 90% of SiC has been transformed from β to α content. [ABSTRACT FROM AUTHOR]

The paper presents a process to restrain edge chipping in grinding segmented mirrors using powder-added filler based on the mechanism of stress wave propagation. Powder of the same material as the mirror is mixed into the filler and added to the splicing gap to reduce tensile stress. The stress wave propagation mechanism in the workpiece with powder-added filler is revealed based on stress wave theory. The influence of the gap thickness on the instantaneous stress state is analyzed by numerical calculation. Stress wave propagation when using powder-added filler is also calculated and compared with the situation using pure filler. Maximum tensile stress can be reduced with smaller gap thickness and powder-added filler. The variation in the size of cracks in scratching tests proves the results derived in the numerical calculations. As verified in contract experiments, cracks near the gap are restrained using filler mixed with powder in the grinding process. [ABSTRACT FROM AUTHOR]

The effect of nitrogen sintering atmosphere on the electrical resistivity of porous silicon carbide (SiC) ceramics with aluminum or boron additives comparing with argon atmosphere was thoroughly discussed and a mechanism was proposed. With using α-SiC starting powder and choosing trace amount of additives, the porosity, microstructure and polytype composition of the porous SiC ceramics sintered under different atmosphere were not found drastically different. Therefore, the effect on electrical properties were able to be discussed straightforwardly in relation to the sintering atmosphere and the two additives. Large difference of electrical resistivity of porous SiC ceramics is found in between the two different sintering atmospheres, in which those with 0.34 mol% of aluminum addition is 106 higher when sintered under argon atmosphere than those under nitrogen atmosphere. The mechanism of nitrogen atmosphere that reduce the electrical resistivity is considered to result from the phenomenon of Auger recombination based on the result of Hall measurements and photoluminescence spectrums. [ABSTRACT FROM AUTHOR]

We report the enhanced erosive wear resistance of SiC/SiC ceramic matrix composites (CMCs) integrated with a knit fabric via high-temperature crystallization of relatively cost-effective first-generation (amorphous) Si–C–O–Al fibers (AM; short for Tyranno™ AM), desingned for use as a sliding component. A pyrocarbon (PyC) interface was formed via dip coating in liquid phenolic resin, and matrix densification was achieved by hot pressing at 1900 °C for 1 h at 30 MPa. The PyC-coated AM fibers exhibited low tensile strength values at temperatures below 1600 °C, which increased significantly at 1900 °C (2.68 ± 0.74 GPa). The hot-pressed AM-SiC/SiC CMCs exhibited typical quasi-ductile fracture in a three-point bending test. The erosive wear of the CMCs was investigated using a slurry erosion test, and the associated mechanism was clarified by laser-microscopy-based 3D profiling and scanning-electron-microscopy-based microstructural examination. The matrix of the hot-pressed AM-SiC/SiC CMCs was dense (1.99 % porosity), rigidly structured, and hard (27.1 ± 2.91 GPa), enabling the CMCs to outperform conventional SiC/SiC CMCs in terms of slurry erosion resistance. [ABSTRACT FROM AUTHOR]

Retention of hydrogen isotopes is a critical concern for operating fusion reactors as retained tritium both activates components and removes scarce fuel from the fuel cycle. Radiation-induced displacement damage in SiC influences the retention of hydrogen isotopes compared to pristine SiC. Deuterium retention in neutron irradiated high purity SiC has been compared to different microstructures of non-irradiated high purity SiC using thermal desorption spectroscopy after gas charging and low energy ion implantation. Experimental results show lower deuterium retention in single crystal SiC than in polycrystal SiC indicating that grain boundaries are key trapping features in unirradiated SiC. Deuterium is released at lower temperatures in neutron irradiated polycrystal SiC compared to pristine polycrystal SiC, suggesting weaker trapping by radiation-induced defects compared to grain boundary trapping sites in the pristine materials. Low energy ion implantation caused a high deuterium release temperature, highlighting the sensitivity of deuterium release behaviour to radiation defect characteristics. First principles calculations have been conducted to identify energetically favourable trapping sites in SiC at the HABcVSi and HTSiVC complexes, and migration barriers between interstitial sites. This helps interpret experimental results and derive effective diffusivity of hydrogen isotopes in SiC in the presence of vacancies. [ABSTRACT FROM AUTHOR]

Silicon carbide whiskers (SiCw) have emerged as ideal nano-fillers for antiwear coatings, but their poor dispersion because of the strong van der Waals interaction and high surface energy limits their application. In this study, we proposed the preparation of chemically bonded phosphate ceramic coating (CBPC) using a Fe 3 O 4 /silicon carbide whisker (MSiCw) hybrid, where the ordered dispersion and orientation of SiCw was achieved through a weak magnetic field. The evolution of the physiochemical structure of MSiCw before and after the modification was investigated by scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis and thermogravimetric analyzer. In addition, tribological experiment and the analyses of microstructure, phase characterization and mechanical performance were carried out to clarify the mechanism of MSiCw content and arrangement on the effect of wear performance. Results show that the addition of MSiCw and the introduction of the magnetic field significantly enhance the mechanical and wear property of CBPC. That is because the oriented arrangement of MSiCw helps to decrease the concentration of local stresses and promote the formation of a transfer film, thus reducing the wear rate and friction coefficient of CBPC. Therefore, CBPC reinforced by aligned SiCw processes excellent tribological properties, which provide thought-provoking ideas for phosphate ceramic coatings to protect metals in harsh environment. [ABSTRACT FROM AUTHOR]

The study investigates the synthesis of mesoporous SiO 2 nanoparticles with uniform spherical morphology via the sol-gel method. A strategic approach of this research was to control the particle size within the sol, achieved by incorporating ammonium polycarboxylate (APC) as an additive. The primary objective of this paper is to utilize these modified particles in the fabrication of ceramic filters for metal melt filtration, aiming to enhance their functional properties. Various analytical methods, including DLS, XRD, FTIR, DTA/TG, XPS, SEM, and TEM/EDS, were employed to evaluate the product formation mechanism during the sol-gel process. It was demonstrated that by controlling the pH within an acidic range of 3, precursor particles containing the Si source formed in sizes below 10 nm within the sol, a phenomenon that is fundamental in controlling the final product size to be under 50 nm. The addition of APC, through an electrosteric mechanism, contributed to the stability of the precursor particles within the sol. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images revealed that the silica nanoparticles possess a spherical shape with a uniform size of approximately 25 nm. Nitrogen adsorption/desorption porosimetry indicated that the nanoparticles have mesoporous with an average pore size of 2.5 nm and a specific surface area of 120 m2/g. This method can be conveniently used to prepare silica nanoparticles with desirable morphology and mesostructure. Polyurethane foam filters were impregnated with nanosilica particles using a slurry casting method. Subsequently, the effects of varying percentages of nanosilica particles in the slurry on the compressive strength, density, and porosity of the ceramic foam filters were examined. Additionally, the impact of silica nanoparticles on the slurry's viscosity was studied using rheometry. The optimal sintering temperature was reported to be 1250 °C. XRD results indicated the formation of mullite phase alongside silicon carbide and alumina phases at 1250 °C. SEM microstructural analysis showed that the mullite phase formed in nanometric dimensions within the ceramic foam bodies. The emergence of the mullite phase in nanometric dimensions within the filter microstructure is one of the factors contributing to the reinforcement and enhancement of refractoriness. [ABSTRACT FROM AUTHOR]

AbstractThis research article explores the mechanical, thermal, and microstructural properties of Basalt Fabric composites that have been improved by incorporating Silicon Carbide (SiC) nanoparticles using electrostatic self-assembly. The study seeks to investigate the efficacy of this interfacial reinforcement technique in enhancing the characteristics of Basalt Fabric composites. The methods utilized in this study involved the creation of composite samples by combining SiC nanoparticles with different concentrations (0.25, 0.5, 0.75, and 1 gram per liter of NH2 solution). This was achieved through the process of electrostatic self-assembly of SiC nanoparticles and the use of the vacuum bagging technique. Thorough testing, which included evaluating the strength and flexibility of the material through tensile and flexural tests, was carried out in accordance with the standards set by ASTM. Additionally, a detailed analysis of the material’s microstructure was conducted using FESEM and FTIR techniques. The results demonstrated that the composite containing 0.5 grams of SiC nanoparticles per liter displayed exceptional mechanical characteristics, exhibiting notable enhancements in both tensile strength and modulus when compared to other compositions. The microstructural analysis verified that the nanoparticles were evenly distributed throughout the matrix and had a robust interfacial bonding. The study concludes that using electrostatic self-assembly of SiC nanoparticles to reinforce the interface is an effective method for improving the performance of Basalt Fabric composites. This method shows promise for use in different engineering fields. [ABSTRACT FROM AUTHOR]

Functionally graded design transforms polymer composites without altering their properties. These composites change only the surface exposed to severe temperatures, leaving the rest unchanged. This study analyses ceramic additions' effects on polymer thermal stability and crystallinity. Dynamic mechanical analysis (DMA) examined viscoelastic behaviour and thermogravimetric stability. Alumina, silicon carbide, and hafnium carbide ceramic powders increase thermal stability. DMA examined how ceramic additives affected composite viscoelasticity. The functionally graded design barely affects ceramic adhesive thermal properties. The ceramic adhesive remained stable at 800 °C with only 6% weight loss, while the other two disintegrated before 600 °C. [ABSTRACT FROM AUTHOR]

The kinetic regularities of the electrօspark sintering of SiC–TiC, SiC–VC composites at a pressure of 45 MPa and the temperatures of 1900 and 2000 °C have been established. At the first stage of the composite compaction process, the addition of TiC, VC impurities in the amount of 20 vol.% to silicon carbide with a dispersion of 2 μm increases the compaction rate by 1.3 and 1.1 times, respectively, and the addition of Ti, V carbides in the amount of 40 vol.% increases the compaction rate by 1.7 and 1.2 times, respectively. At the second stage of the compaction process, when Ti, V carbides are added in the amount of 40 vol.%, the compaction increases from 70% in silicon carbide to 99.9% in the 60SiC–40TiC composite and 91.2% in the 60SiC–40VC composite. Solid-phase sintering in composites with an admixture of titanium carbide is better than in composites with an admixture of vanadium carbide due to an increase in interaction at the phase boundaries: the interaction zone increases from ~1.0 μm at the boundaries of silicon carbide and vanadium carbide grains to ~1.5 μm at the boundaries of silicon carbide and titanium carbide grains. [ABSTRACT FROM AUTHOR]

Interest in exploiting physical properties of nanocomposite materials continues its upward trajectory, which can lead to advancements in a variety of application domains, including sensing and optoelectronics. Here, silica (SiO2) and silicon carbide (SiC)-reinforced polyethylene oxide (PEO) nanocomposite membranes (NMs) are fabricated by a casting method. The SiO2-SiC nanoparticle (NP) content is changed between 0–5.1 wt.%, followed by characterizing microstructural and optical properties of the resulting NMs. The successful reinforcement of SiO2 and SiC NPs within the matrix is described using different analytical mechanisms. The absorbance of PEO/SiO2-SiC NMs increases to 74.2%, and their transmittance decreases to 46% at a wavelength of λ = 560 nm when the SiO2-SiCNP content increases to 5.1 wt.%. The absorption coefficient of pure PEO (6591 cm−1) is found to increase to 8450 cm−1 for the 5.1 wt.% NP content at a photon energy of 4.14 eV. Meanwhile, increasing the NP content from 0 to 5.1 wt.% decreases the allowed and forbidden indirect transition energy gaps from 3.7 to 3.3 eV and 3.6 to 3.2 eV, respectively. Alternatively, increasing trends are observed for the refractive index (from 1.94 to 2.64) and extinction coefficient (from 5.47 × 10–3 to 19.76 × 10–3) at λ = 780 nm. Also, the increased SiO2-SiCNP content enhances the real and imaginary parts of the dielectric constant of the NMs. [ABSTRACT FROM AUTHOR]

Based on the processing of a backscattered electron digital image of the ground surface and the results of X-ray spectral microanalysis, a method for determining the intensity of titanium alloy charging by wear products of an abrasive tool made of silicon carbide is developed. The numerical values of the charging intensity and the laws of its distribution are determined. The effect of radial feed on the charging intensity is established. [ABSTRACT FROM AUTHOR]

Induction heating technology plays a significant role in heating applications with its high efficiency, fast response, and precise control ability. Traditional resonant inverter-based systems face problems such as complexity, lack of flexibility, and low efficiency in multi-load situations. To overcome these issues, a new non-resonant full-bridge multiple-output inverter topology using silicon carbide (SiC) semiconductor devices is presented. While the system is simplified by eliminating resonant components, efficiency is increased thanks to SiC devices. In the study, a coil design methodology focusing on coil resistance and inductance is presented to optimize energy transfer and maximize system performance. Load-sensing and advanced frequency-modulation techniques are integrated to provide precise and independent power regulation in multi-loads. Thus, the efficiency of energy distribution and system robustness are increased. The proposed topology offers heating performance that provides homogeneous heat distribution. The developed prototype was proven to operate reliably with high efficiency under different load conditions and was suitably applied for domestic induction heating applications. An efficiency of 96.78% was achieved at a 50 kHz operating frequency and 2000 W power level. [ABSTRACT FROM AUTHOR]

Novel catalytic silicon carbide membrane filters (SCMFs) are synthesized with Co/Al–layered double hydroxide (Co/Al-LDH)-coated silicon carbide powder. After capsuled in a self-designed membrane shell, the SCMFs are utilized in activating persulphate for aniline degradation. Thermal analysis conducted via TG/DTG/DSC examination shows that the heating treatment is beneficial in elevating the activating ability of SCMFs, and the derived Co3O4 displays superior catalytical efficiency than Co/Al-LDHs precursor. The XRD patterns and SEM images indicate the sheet-like Co/Al-LDHs are uniformly coprecipitated throughout the surface of SCMFs. Within 20 min, around 95% of aniline is eliminated under 0.7 m of flow velocity and 8:1 of persulphate to aniline ratio. Three-dimensional fluorescence and GC chromatography reveal that distinct by-products exist in the early stage of the aniline degradation process between the sintered and non-sintered Co/Al-LDH-coated SCMFs. The integration strategy of Co/Al-LDH coatings and heating treatment endows traditional SCMFs with robust catalytic properties for engineering-oriented applications in wastewater treatment. [ABSTRACT FROM AUTHOR]

This study presents the development and optimization of pyramidal microwave absorbers designed for efficient electromagnetic interference (EMI) reduction in anechoic chambers. Based on prior research, this work transitions from conventional flat cement-carbon absorbers to a novel pyramidal design, incorporating silicon carbide (SiC) as ceramic materials. Introducing ceramic materials into the cement-carbon composite aims to enhance absorption across a broader frequency range while maintaining structural integrity. The study evaluates five sets of pyramidal absorbers with varying SiC content within the 1-12 GHz frequency range. Reflectivity performance was assessed using the naval research laboratory (NRL) Arch free space method at a 0° incidence angle. Among the tested absorbers, the set containing 10% SiC demonstrated superior performance, achieving minimum and maximum reflectivity values of -26.6215 and -55.2752 dB, respectively, particularly in the C-band. The findings highlight the significant impact of material composition and porosity on the absorber's effectiveness, providing valuable insights for the future design of highperformance EMI absorbers. [ABSTRACT FROM AUTHOR]

A broadband microwave composite metamaterial absorber based on the Debye model, consisting of triple dielectric loss layers and different-ordered metallic fractal pattern vertical layers, has been proposed. The research results show that when all the three dielectric layers are silicon carbide fiber (SiCf), the composite absorber presents two intense absorption bands with a bandwidth of 5.44 GHz. The length (l) of the metallic pattern and thickness (t) of the top dielectric layer can effectively regulate the reflection loss performance. Additionally, the effective absorption bandwidth increases to 13.44 GHz when the relative absorption bandwidth reaches about 119.15% by replacing SiCf at the top dielectric layer with the dielectric loss materials which satisfy the Debye model. The research results show that the absorption bandwidth obviously increases with dielectric loss materials of distinct Imε. Furthermore, the proposed fractal pattern shows robustness to the variation of complex permittivity spectrum, expanding the range of suitable dielectric materials for composite broadband metamaterial absorbers. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) fiber is a high-performance ceramic fiber mainly prepared by the polymer-derived ceramics (PDC) method. However, balancing the precursor's ceramic yield and spinnability is challenging in the preparation process. Herein, we proposed a new strategy, chemical bonding with PCS to form a high cross-linked network structure, utilizing the flexibility and high aspect ratio within MWCNTs. As a result, based on the spinnable PCS (57.58 %), only the incorporation of 0.05 wt% MWCNTs increase the ceramic yield by 21.66 %–70.05 % and 1 wt% MWCNTs achieved as high as 81.44 % when pyrolyzed at 900 °C. Moreover, the hybrid precursors showed good spinnability, except for the 1%-MWCNTs/PCS. In addition, the presence of chemical bonding and cross-linking structures has been thoroughly proven, and the mechanism behind the increase in ceramic yield has been further explored. MWCNTs occupied cross-linking sites and formed cross-linked structures to effectively reduce weight loss during thermal cross-linking in the 300–500 °C temperature range, thereby increasing ceramic yield. The increment of spinnable PCS in the ceramic yields can effectively reduce the preparation cost and enhance the performance of the SiC fibers using the PCS method. [ABSTRACT FROM AUTHOR]

This study investigates Beam Line Absorbers (BLAs) for the Hefei Advanced Light Facility (HALF). A ferrite-based BLA prototype was developed, demonstrating high-power handling capacity up to 10 kW, ultra-high vacuum performance better than 6. 5 × 1 0 − 1 0   mbar, and high absorption efficiency in critical frequency ranges. Subsequently, more compact designs with reduced longitudinal length were explored, investigating ferrite-only, silicon carbide (SiC)-only, and hybrid configurations through RF simulations. Based on preferred absorption efficiency, ferrite-only and hybrid BLA structures were further analyzed under high-power conditions. Referencing test results, multiphysics simulations were conducted under 3 kW absorbed power. The hybrid design, comprising two rings of ferrite tiles and one ring of SiC tiles, improved the temperature distribution of the absorbing materials. Extrapolating to 11 kW absorbed power, this design reduced the maximum temperatures on absorbing tiles by up to 40 ° C compared to the ferrite-only design. The hybrid design offers a balanced solution that combines effective HOM damping with enhanced thermal performance, improving the long-term operational stability of BLAs. [ABSTRACT FROM AUTHOR]

\nHighlightsReaction-bonded silicon carbide (RB-SiC) is a typical brittle material. Surface removal modes such as brittle fracture and ductile groove will directly influence the performance of RB-SiC. This study proposes an improved YOLOv8 intelligent recognition method to enhance the accuracy and efficiency of recognising material removal mode on the surface of RB-SiC. The model employs the lightweight YOLOv8n architecture with a Slim-neck structure to reduce network parameters and accelerate detection speed, integrates the Coordinate Attention (CA) module for enhanced feature extraction, and utilises the Wise-IoU loss function to improve loss calculation. The experimental results showed that the original YOLOv8 model achieved a mean Average Precision (mAP) of 84.7% and the proposed model achieved an mAP of 88.6%, outperforming the original by 3.9%. Meanwhile, the mapping relationship between the material removal mode and the grinding parameters on the surface of RB-SiC ceramics was established. Based on the material removal mechanism, advanced approaches for evaluating the quality of the grinding surface were explored. A new method for detecting material removal modes on RB-SiC surfaces using improved YOLOv8 is proposed.The slim-neck structure and coordinate attention module optimise the model for lightweight, efficient, robust performance.The model was validated by comparison and ablation tests employing the dataset obtained from RB-SiC precision grinding.Mapping the relationship between grinding parameters and the material removal modes of RB-SiC surface reveals strategies for reducing brittle fracture damage.A new method for detecting material removal modes on RB-SiC surfaces using improved YOLOv8 is proposed.The slim-neck structure and coordinate attention module optimise the model for lightweight, efficient, robust performance.The model was validated by comparison and ablation tests employing the dataset obtained from RB-SiC precision grinding.Mapping the relationship between grinding parameters and the material removal modes of RB-SiC surface reveals strategies for reducing brittle fracture damage. [ABSTRACT FROM AUTHOR]

Multifunctional polymer composites containing micro/nano hybrid reinforcements have attracted intensive attention in the field of materials science and engineering. This paper develops a multi-phase analytical model for investigating the effective electrical conductivity of micro-silicon carbide (SiC) whisker/nano-carbon black (CB) polymer composites. First, CB nanoparticles are dispersed within the non-conducting epoxy to achieve a conductive CB-filled nanocomposite and its electrical conductivity is predicted. Some critical microstructures such as volume percentage and size of nanoparticles, and interphase characteristics surrounding the CB are micromechanically captured. Next, the electrical conductivity of randomly oriented SiC-containing composites in which the nanocomposite and whisker are considered as the matrix and reinforcement phases, respectively, is estimated. Influences of whisker aspect ratio and volume fraction on the effective electrical conductivity of the SiC/CB-containing polymer composites are explored. Some comparison studies are performed to validate the accuracy of the model. It is observed before the percolation threshold that the addition of nanoparticles with a uniform dispersion can improve the electrical conductivity of the polymer composites containing SiC/CB hybrids. Moreover, the results show that the electrical conductivity is more enhanced by the decrease in nanoparticle size. Interestingly, the composite percolation threshold is significantly reduced when SiC whiskers with a higher aspect ratio are added. This work will be favorable for the design of electro-conductive polymer composites with high performances. [ABSTRACT FROM AUTHOR]

This study presents a novel topology designed to enhance the energy efficiency and quality of IGBT-based high-frequency rectifiers, which are commonly used to supply the high DC power required in industrial applications. In the proposed design, traditional silicon semiconductors are replaced with advanced SiC semiconductors, resulting in reduced switching losses and improved energy quality due to higher frequency switching. The new topology also offers solutions to challenges such as inrush current, reverse energy flow, and high DC output voltage issues typically encountered in IGBT-based rectifiers. The goal is for this topology to maximize efficiency and applicability. The proposed design is simulated in the Simulink environment, with the results presented in the findings section. To highlight the advantages of the new topology, the electrical parameters of the widely used three-phase full-bridge IGBT rectifier topology are employed for comparison. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) metal oxide semiconductor field-effect transistors (MOSFETs) are a future trend in traction inverters in electric vehicles (EVs), and their thermal safety is crucial. Temperature-sensitive electrical parameters' (TSEPs) indirect detection normally requires additional circuits, which can interfere with the system and increase costs, thereby limiting applications. Therefore, there is still a lack of cost-effective and sensorless thermal monitoring techniques. This paper proposes a high-efficiency datasheet-driven method for sensorless estimation utilizing the third-quadrant characteristics of MOSFETs. Without changing the existing hardware, the closure degree of MOS channels is controlled through a dual-gate bias (DGB) strategy to achieve reverse conduction in different patterns with body diodes. This method introduces a MOSFET operating current that TSEPs are equally sensitive to into the two-argument function, improving the complexity and accuracy. A two-stage current pulse is used to decouple the motor effect in various conduction modes, and the TSEP-combined temperature function is built dynamically by substituting the currents. Then, the junction temperature is estimated by the measured bus voltage and current. Its effectiveness was verified through spice model simulation and a test bench with a three-phase inverter. The average relative estimation error of the proposed method is below 7.2 % in centigrade. [ABSTRACT FROM AUTHOR]

The Food and Drug Administration (FDA) has banned gamma-Hydroxybutyric acid (HBA), which is widely utilised for drug-facilitated sexual assaults across the world. As a result, it is crucial for law enforcement and drug organisations to detect HBA in biological settings. There has been substantial interest in 2D chemical nanosensors for gaseous and biological molecule detection. This paper studied the sensing performance of bare and Ir-decorated SiC nanosheets for HBA detection through the TPSS density functional. The bare SiC nanosheets were found to have insignificant responsiveness to HBA (almost 7.3 at 298 K) due to their small binding energy with the drug molecules (−0.26 eV). The Ir-decorated SiC nanosheets, however, showed superb performance in adsorbing HBA on an Si–C bond, with a binding energy of −2.54 eV. The Ir-decorated SiC nanosheets enabled strong HBA adsorption (binding energy = −1.35 eV). Therefore, the decoration of SiC sheets with Ir atoms remarkably enhanced their responsiveness to HBA molecules from 7.3 to 495.4. The recovery time for the desorption of HBA molecules from the surface of the Ir-decorated SiC nanosheets was estimated to be 1.09 s. It was concluded that Ir-decorated SiC nanosheets are a promising nanosensor to detect HBA. [ABSTRACT FROM AUTHOR]

Silicon carbide and an aluminum alloy (SiC/AlSi12) composite are obtained during the pressurized casting process of the aluminum alloy into the SiC foam. The foam acts as a high-stiffness skeleton that strengthens the aluminum alloy matrix. The goal of the paper is to describe the behavior of the material, considering its internal structure. The composite's structure is obtained by using X-ray computing tomography. The thorough computer tomography analysis allows for the high-precision identification of the shape and distribution of the pores in the matrix. The computational model prepared in the framework of the peridynamics method takes into account the pores and their shape. The pores in the structure appeared in the fabrication process. The impact of a steel ball is studied employing the peridynamics method. The sample without any porosity and a porous one were considered during the analyses. It has been found that the porosity of the matrix influences the plastic strain development, but the damage parameter in the skeleton is not affected significantly. The damage advancement in the skeleton during the process is practically identical in both cases. The equivalent plastic strain field is much smoother in a non-porous matrix than in a porous one. The porous matrix has high equivalent plastic strain concentrations, much higher than the non-porous matrix. The shape of the sample is affected by the porosity of the matrix. The sample with a porous matrix tends to fragment, and it shows a tendency towards spallation when in close contact to the surface with the base. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) foam ceramics demonstrate excellent filtration efficiency as filter supports due to their complex pore network and chemical stability. However, their fabrication demands high sintering temperatures (above 2100 °C), resulting in substantial energy consumption and production costs, which restricts their wider use in separation and purification application processes. To address this, we utilized fly ash, a by-product of coal combustion rich in inorganic Al₂O₃, as a sintering aid to develop a porous silicon carbide–alumina foam ceramic (SAFC) and investigated the effects of Al₂O₃ on its performance. Additionally, we introduced SAFC as an adsorbent material, synthesizing the fluoride adsorbent (La@SAFC) and evaluating its fluoride removal efficacy through batch experiments. Results indicate that Al₂O₃, as a sintering aid, promotes the sintering process by forming a liquid phase that enhances Si and C diffusion at lower sintering temperatures. SAFC containing 16 wt% Al₂O₃ achieved optimal porosity, low bulk density, and compressive strength at a sintering temperature of 1150 °C. The addition of Al₂O₃ also facilitated mullite formation, significantly enhancing the ceramic's mechanical properties. However, excess Al₂O₃ can produce an overabundant liquid phase and gas release, potentially compromising the mechanical integrity of SAFC. Batch experiments revealed that La@SAFC exhibited strong fluoride removal from water containing competing ions across a pH range of 3–7, achieving effluent within strict discharge standards. Mechanism analysis suggested fluoride removal via ion exchange and electrostatic interaction. La@SAFC maintained high fluoride removal efficiency across five regeneration cycles, underscoring its promise for practical applications. [ABSTRACT FROM AUTHOR]

Slurry infiltration method has been widely used as a preliminary step in preparing dense and multifunctional fiber reinforced SiC ceramic matrix composites. However, the infiltration efficiency of slurry is low mainly due to its insufficient stability, specifically manifested as the limited weight gain of composite after slurry infiltration. The aim of this study is to improve the infiltration efficiency of slurry by improving its stability, while maintaining its low viscosity and high particle concentration. In this study, by adjusting the particle size, two SiC slurries with identical high particle concentration (50 wt.%) and similar low viscosities (less than 10 mPa·s) but different stabilities were obtained and then applied in the infiltration process of composites. The stability of slurry can be highly improved by decreasing the particle size. The weight gain of composites after infiltration of high stability slurry (sedimentation time exceeding 35 h) is more than twice that of low stability slurry (sedimentation time nearly 1 h). Combined with chemical vapor infiltration method, the final composite using high stability slurry exhibits increased density, reduced porosity and enhanced mechanical performance. [ABSTRACT FROM AUTHOR]

The use of submicron silicon carbide powder as a raw material is crucial for preparing high-performance silicon carbide ceramics. However, its strong absorption of ultraviolet light makes stereolithography of submicron silicon carbide powder challenging. In this study, submicron SiC particles, photosensitive resin, and photoinitiator were used as raw materials to prepare SiC ceramics via stereolithography combined with a pressureless sintering method. The effects of ultraviolet wavelength, type, and content of photoinitiator on the curing properties of submicron SiC ceramic slurry were investigated. The results showed that the curing thickness of the SiC ceramic slurry significantly increased with the increasing ultraviolet wavelength. Compared to photoinitiators TPO and 396, photoinitiator 819 exhibited a better curing effect. Additionally, increasing the photoinitiator content facilitated the generation of more free radicals in the SiC ceramic slurry at low light intensity, thereby improving its ultraviolet absorption characteristics. When the dosage of photoinitiator 819 was 8.8 %, the SiC slurry achieved the best curing performance, with a single-layer curing thickness of 50 μm and a sintering density of 95 % for SiC ceramics. [ABSTRACT FROM AUTHOR]

In medium- and high-power-density applications, silicon carbide (SiC) metal-oxide semiconductor field effect transistors (MOSFETs) are often connected in parallel increasing the current capability. However, the current sharing of paralleled SiC MOSFETs is affected by the mismatched technical parameters of devices and the deviated power circuit parasitic inductances, even if power devices are controlled by a single gate driver. This leads to unevenly distributed power losses causing different stress between SiC MOSFETs. As a result, unbalanced current sharing increases the probability of severe power switch(es) and system failures. For over a decade, the current imbalance issue between parallel-connected SiC MOSFETs has concerned the scientific community, and many methods and techniques have been proposed. However, most of these solutions are impossible to realize without the necessity of screening power devices to measure their technical parameters. Consequently, system costs significantly increase due to the expensive equipment for screening SiC MOSFETs. Also, transient current imbalance is the main concern of most papers, without addressing static imbalance. In this paper, an innovative approach is proposed, capable of suppressing both static and transient current imbalance between paralleled SiC MOSFETs, under both symmetrical and asymmetrical layouts, through an improved active gate driver and without the requirement for any power device screening process. Additionally, the proposed solution employs a self-sustaining algorithmic approach utilizing current sensors and a field-programmable gate array (FPGA). The functionality of the proposed solution is verified through experimental tests, achieving current imbalance suppression between two paralleled SiC MOSFETs, actively and autonomously. [ABSTRACT FROM AUTHOR]

This work explores the principle of utilizing gallium nitride devices as a gate driver for silicon carbide power devices. As silicon has long reached its performance limits, Wide Bandgap semiconductors such as gallium nitride and silicon carbide have emerged as promising alternatives due to their superior characteristics. However, few publications suggest using a gallium nitride-based gate driver for silicon carbide, high-voltage power devices. Unlike standard voltage source gate drivers, this paper proposes a novel bi-polar current source resonant gate driver topology using gallium nitride transistors as a gate drive circuit for silicon carbide power switching. The driver receives a single input supply and pulsed width modulation signal, producing a high current bi-polar gate driving signal. The gate driver is validated by employing the proposed gate driver to a high-power silicon carbide transistor in a resonant boost converter. The experimental results show that the new gate driver recovers the gate charge wasted energy and provides high performances in varying high voltage loads at a 2.5 MHz switching frequency while reducing the gate losses by 26%. [ABSTRACT FROM AUTHOR]

Featured Application: Using the proposed photodetector (TaC: Cu/4H silicon carbide (SiC)) could broaden the use of 4H SiC-based devices beyond traditional UV detection, extending into near-ultraviolet and visible light regions, particularly at 405 nm. The high responsivity and photocurrent make it suitable for high-temperature optoelectronic applications that require reliable and efficient light detection across a wider range of wavelengths. Its possible applications include environmental monitoring, flame detection, and UV-visible optical sensing, addressing the demand for high-performance photodetection in extreme conditions. Photodetectors (PDs) based on 4H silicon carbide (SiC) have garnered significant interest due to their exceptional optoelectronic properties. However, their photoresponse is typically restricted to the ultraviolet (UV) region, with limited light absorption beyond 380 nm, which constrains their utility in visible light detection applications. To overcome this limitation, an efficient photodetector was developed using an alloy with TaC (80%) and Cu (20%) on a 4H n-type SiC substrate, enabling effective light detection at 405 nm. The device exhibited high performance with a high photoresponsivity of 1.66 A W − 1 and a specific detectivity of 2.69 × 10 8 Jones at 405 nm. The superior performance of the device is ascribed to the enhanced electrical conductivity and optical absorption of the TaC: Cu layer on the 4H SiC substrate, particularly in the near-ultraviolet region. This photodetector combines ease of fabrication with significant performance improvements, expanding the potential applications of 4H SiC in high-temperature optoelectronics. It also introduces a promising pathway for enhancing 4H SiC-based photodetection capabilities across broader spectral ranges. [ABSTRACT FROM AUTHOR]

As a kind of metal matrix composites, silicon carbide particulate reinforced aluminum alloy composites (SiCp/Al) have been widely applied in numerous fields. However, it is still difficult to process this composite material with electrical discharge machining (EDM) at present. To address this problem, this study introduces a novel rotary electrochemical discharge – chemical composite machining (RECDM-CM) method. This method uses rotating electrodes and workpieces to improve the flushing effect of working medium and utilizes the electrolysis to reduce the recast layer thickness. The chemical reaction between sodium carbonate (Na2CO3) and aluminum oxide (Al2O3) at high temperatures is used to remove the non-conductive Al2O3 in this composite machining. Rotary electrochemical discharge – chemical composite machining is used to process silicon carbide particulate reinforced AA2009 aluminum alloy composites with the silicon carbide volume fraction of 55%. The experimental results reveal that the material removal rate (MRR) of rotary electrochemical discharge – chemical composite machining is 5.2 times that of rotary electrical discharge machining, and its relative tool wear rate (RTWR) is 37.42% of rotary electrical discharge machining. The recast layer thickness is reduced to less than 13 μm via rotary electrochemical discharge – chemical composite machining. [ABSTRACT FROM AUTHOR]

The top-seeded solution growth (TSSG) method is an emerging technique for the production of silicon carbide (SiC). Due to its advantage of lower growth temperature compared to the physical vapor transport method, it holds significant potential in the preparation of Al-doped SiC. In this study, a global numerical model calculating heat and mass transfer was established to investigate the impact of solution radius and height, coil position, and rotational speed of the seed crystal on the flow pattern and carbon transport. The results indicated that a meticulous determination of these growth parameters could enhance both carbon transport and growth rate. Furthermore, abundant transient calculation results were utilized to train back-propagation (BP) neural networks to extract the correlation between growth parameters, growth rate, and Al concentration. The optimal parameters were ultimately obtained using the non-dominated sorting genetic algorithm (NSGA-II). The Al concentration calculated in the solution under the optimal growth conditions demonstrated that the evaporation of Al was sufficiently low to satisfy the p-type doping requirement. This study provides valuable insights for the future development of a TSSG system tailored for the rapid growth of Al-doped SiC. [ABSTRACT FROM AUTHOR]

The properties of polymeric composites have often been altered with the incorporation of fillers. In this study, the poly(methyl methacrylate) (PMMA) was filled with silicon carbide nano-particles (SiC). The PMMA/SiC composite films were prepared through solution casting by using acetone as solvent. The different loading of SiC ranging from 0.25 wt% to 1.00 wt% were incorporated into the PMMA matrix. The effect of SiC loading and silane coupling agent on PMMA/SiC composite films in terms of mechanical, physical, and morphological properties was investigated. It was found that the increasing SiC loading and the silane treatment had increased the tensile strength and Young’s modulus but reduced the elongation at the break of PMMA/SiC composite films. At 0.75 wt% of silanized SiC, the tensile strength of the composite films was found to increase by 25 % from 30 to 37.5 MPa as compared to the virgin PMMA. Besides, the hardness of composite films was also increased with SiC loading and silane treatment. The presence of 1.00 wt% silanized SiC had increased 21.7% the hardness of the virgin PMMA, resulting in the increase of Shore A value from 69 to 84. By using silane treatment, better filler-matrix interaction was established as smoother fracture surfaces were observed through SEM micrographs and higher d-spacing was found in X-ray diffraction (XRD) patterns. The PMMA/SiC composite films prepared were suitable to be used in sporting goods, additive manufacturing, and environmental and protective coatings. [ABSTRACT FROM AUTHOR]

In this study, silicon carbide (SiC) was prepared from sol–gel process combined with subsequent carbothermal reaction. Then through hydrothermal method synthesized xFe/SiC-700 and 30Fe/SiC-T catalysts. The catalysts were characterized by XRD, SEM/TEM, XPS, and H2-TPR. The ammonia decomposition performances of the catalysts were assessed in a fixed-bed reactor. Tests revealed that SiC has a high specific surface area and can evenly diffuse Fe2O3 nanoparticles, thus exposing more active sites and raising the adsorption capacity of catalysts surface. The interaction of Fe2O3 and SiC is stronger, the catalyst activity is better. The surface basicity of catalyst is higher, decomposition ability of ammonia is stronger. 30Fe/SiC-700 catalyst has the best activity among the synthesized catalysts for hydrogen production by ammonia decomposition. The ammonia conversion rate can reach up to 90.16%, and the hydrogen generation can rate reach up to 30.19 mmol·min−1·gcat−1 at 600 °C at 30,000 mL·gcat−1·h−1. Moreover, the catalytic activity is efficient and stable after continuous reaction at 600 °C for 160 h. Ammonia decomposition: The silicon carbide supported iron oxide catalyst was prepared, which effectively cracked ammonia to produce COX-free H2. [ABSTRACT FROM AUTHOR]