Production Of Silicon Carbide Research Articles

APPLICATION OF SPARK PLASMA SINTERING AS A METHOD FOR PRODUCING NEW CERAMIC MATERIALS FROM SILICON PRODUCTION WASTE

The article presents some existing methods of producing silicon carbide, forms and types of silicon carbide, various compositions and formulations, production technology. The authors proposed a new method of processing silicon production waste - microsilica by spark plasma sintering with a carbon-containing reducing agent (soot) which produces a silicon carbide compound. Studies have shown that sintered silicon carbide has improved strength properties. Thus, the possibility of application of production wastes to create new composite materials characterized by a certain complex of properties is confirmed.

Effect of leakage of volatile synthesis products on silicon carbide yield in an electrothermal fluidized bed reactor

Effect of leakage of volatile synthesis products on silicon carbide yield in an electrothermal fluidized bed reactor

Spark plasma sintering of SiC-based bulk materials from carbonaceous residue of rice husk thermal processing

Relevance. The search for a useful application of carbonaceous residues of rice husks thermal processing. These residues due to high silicon content in the inorganic part can potentially be used to produce silicon carbide – an important functional material for various fields of science and technology. Useful utilization of this waste will allow not only solving the environmental problem associated with their inefficient application and formal disposal, but also obtaining value-added products in the form of SiC-based ceramics. Aim. To obtain SiC-based bulk products from carbonaceous residues of rice husk thermal processing by spark plasma sintering with a minimum number of additional stages of feedstock processing. Objects. SiC-based bulk products obtained using carbonaceous residues of rice husk thermal processing. The samples were obtained by spark plasma sintering at 1800 °C, pressure of 60 MPa and holding time of 10 minutes. Methods. Spark plasma sintering; X-ray diffractometry (X-ray phase analysis); scanning electron microscopy; vacuumless arc discharge synthesis method. Results. The authors have carried out the experimental studies to assess the possibility of applying carbonaceous residue of rice husk thermal processing as a precursor for the synthesis of silicon carbide in bulk (ceramics) and dispersed (powder) forms. A series of experiments on spark plasma sintering of carbonaceous residue from rice husk thermal processing in the initial and milled form, with SiO2 silica sand additives, as well as with the use of silicon carbide powders synthesized from carbonaceous residue by vacuumless arc discharge method were implemented. The latter is performed within a one-stage fast-flowing process in an air environment and does not require the use of a vacuum system. Preliminary results demonstrated the possibility of obtaining bulk products and dispersed powders based on silicon carbide with a content of at least 50 and 60 wt %, respectively, and indicate the prospects of further increasing phase purity by optimizing spark plasma sintering and vacuumless arc discharge synthesis.

Bimodal powder optimization in SiC binder jetting for mechanical performance

Binder jetting (BJ) additive manufacturing has emerged as a promising technique for batch production of complex silicon carbide (SiC) ceramic components. However, the utilization of coarse powder in BJ often leads to lower density and strength in green parts and final composites compared to conventional fabrication methods. This study aims to enhance the mechanical performance of SiC ceramics through a novel bimodal SiC powder formulation for BJ, complemented by phenolic resin impregnation and pyrolysis (PRIP) and liquid silicon infiltration (LSI). The optimal ratio of bimodal powder, comprising 75 % coarse and 25 % fine powder, was determined through a comprehensive analysis of the microstructure and properties at various stages of the preparation process. The bimodal powder achieves a packing density of 48.3 % and exhibits satisfactory flowability. Notably, the density of the green part reaches 1.78 g/cm3, which is 31 % and 4.7 % higher than that of unimodal fine and coarse powders, respectively. Following the LSI process, the final Si-SiC composites display a high flexural strength of 276.6 ± 13.3 MPa and fracture toughness of 3.52 ± 0.12 MPa·m1/2. These values represent increases of 42.4 % and 25.3 %, respectively, compared to the composites derived from unimodal coarse powder. The material compositions and fabrication strategies proposed in this work offer an effective pathway for creating high-performance SiC ceramic composites via binder jetting.

Possibility of using boric acid and glutinous rice flour as additive for producing silicon carbide ceramic via pressureless solid-state sintering

This research aimed to investigate the possibility of using the mixture of boric acid and glutinous rice flour as a cost-efficient alternative additive for producing silicon carbide (SiC) ceramic sintered at 1800℃ via pressureless solid-state sintering. The results indicated that the addition of boric acid- glutinous rice flour mixture (10 wt%) in an appropriate ratio (0.5 by molar ratio) into the SiC mixture (90 wt%) enhanced the densification and flexural strength of sintered SiC samples. However, increasing boric acid/glutinous rice flour ratio reduces density and flexural strength. The 5.45 wt% carbon content was sufficient to remove the oxide layer of the SiC surface and improve the properties of SiC ceramic. In summary, the boric acid-glutinous rice flour mixture has a high potential to be used as an additive for producing dense and porous SiC ceramics via pressureless solid-state sintering.

Thermomechanical characterization of brazed SiC assemblies for receivers of CSP plants

In order to increase the performance of solar tower power plants, it is necessary to improve the receivers in order to reach higher temperatures or a longer life span. Silicon carbide is a promising material for this purpose, but large parts cannot be made in one piece: a joining process is required. BraSiC® brazing alloys have been developed to produce silicon carbide assemblies that can withstand temperatures of about 1000°C, but their thermomechanical behavior is poorly understood. The understanding of the failure mechanisms as well as the knowledge of the limits of use of these materials is essential to be able to produce reliable receivers. In this article, two types of BraSiC® braze have been studied: CEA 0 and CEA 1, using the IMPACT test bench, specifically developed to characterize materials under concentrated solar flux. The results show that the CEA 1 braze is more resistant to thermomechanical stresses. Two damage mechanisms of the brazed joints were also identified using acoustic emission.

Design and performance characterization of highly wettable core-shell structured SiC@C composites

SiC@C composites are extensively used in high-temperature metallurgy owing to their distinctive physicochemical properties. In this study, SiC@C composites with a core-shell structure were synthesized using silicon powder and Fe2O3 as the silicon source and catalyst, respectively. The effect of various temperatures on the synthesis of the SiC@C composites was investigated. The results indicated that a SiC whiskers layer covers the graphite surface at 1600 °C. At this temperature, the production of silicon carbide reaches 9.2 %. Transmission electron microscope (TEM) revealed that the preferred growth orientation of SiC was the (111) crystal plane. Based on density functional theory, the adsorption properties of different crystal planes of SiC crystals and their interactions with Fe atoms on the crystal surface were investigated. The results showed that the adsorption properties of different SiC crystal planes varied, with the (111) crystal plane exhibiting the strongest adsorption ability. In the presence of Fe atoms, the adsorption properties of the (111) crystal plane reaches to a value of −2686.5253 Ha, indicating that Fe atoms can promote the adsorption of other atoms or molecules on the surface of SiC crystals. Additionally, the wettability of the SiC@C composites was improved, as evidenced by the decrease in the contact angle from 109° to 46°.

Magnesium thermal SHS of silicon carbide using carbon fibers as a carbon source

Studies on the production of silicon carbide by self-propagating high-temperature synthesis (SHS) have been carried out. To provide the necessary energy for the process, the synthesis was carried out by magnesium-thermal reduction of silicon dioxide in an argon atmosphere. A special feature of this study is the use of carbon fibers as a carbon source. It has been determined that during magnesium-thermal synthesis, hexagonal particles with a size of 1‒2 µm and a thickness of about 0,2‒0,3 µm are mainly formed. X-ray phase analysis showed the predominant formation of silicon carbide cubic syngony.

ВЫПЛАВКА ВЫСОКОКАЧЕСТВЕННОГО ЧУГУНА В ЭЛЕКТРОДУГОВОЙ ПЕЧИ С КИСЛОЙ ФУТЕРОВКОЙ

The possibility of reducing the cost of producing high-strength cast iron by smelting the initial low-carbon melt in an electric arc furnace with an acidic furnace with subsequent carburization and silicification by waste of the return charge of silicon carbide production was considered.

Multilayer Graphene-Coated Silicon Carbide Nanowire Formation Under Defocused Laser Irradiation

Graphene-coated silicon carbide (SiC@C) core–shell nanostructures have attracted attention in the fields of energy storage and nanoelectronics. In this study, multilayer graphene-coated silicon carbide (SiC) nanowires were obtained through the laser irradiation of a mixture target of graphite powder and silicon (Si) grinding sludge discharged from Si wafer manufacturing. Laser irradiation was performed using an ytterbium (Yb) fiber pulsed laser with a pulse width of 10 ms and a wavelength of 1070 nm with various defocus distances. The effect of laser defocusing on the morphology of the generated nanostructures was investigated. Results showed that nanowires were produced under the defocused conditions, and nanoparticles were observed at the on-focus position. The products obtained under all defocused conditions showed a core–shell structure, and the SiC nanowires were covered by graphene layers. The aspect ratio of the nanowires increased with the defocus distance. Observation of the laser-induced plume using a high-speed camera showed that when the laser was defocused, the plume propagation speed slowed down, and the shape of the plume changed to a swirling vortex. The nanowire formation was closely related to the propagation speed and shape variation of the plume. This successful production of SiC@C core–shell nanowires from Si waste opens up the possibility of the sustainable development of new materials for energy storage and nanoelectronics.

3D printing Si3N4-bonded SiC refractories fabricated using colloidal films-containing slurries based on non-spherical SiC and Si powders

Stable slurries for Si3N4-bonded SiC refractories for direct ink writing (DIW) were successfully prepared from a mixture of non-spherical silicon carbide (SiC) and silicon (Si) powders with an average particle size of D50 = 41.98 μm. The rheological properties and printability of slurries prepared using polyvinyl alcohol (PVA; 4–16 wt %) or hydroxypropyl methylcellulose (HPMC, 0.5–2 wt.%) were investigated with the effect of sintering temperature on the mechanical performance, phase, and microstructure of Si3N4-bonded SiC refractory products. The results indicated that slurries prepared with the HPMC solution showed better printability than those prepared with the PVA solution because colloidal films formed by HPMC in slurries play a role in encasing particles, preventing solid−liquid separation and contributing to plasticity and lubrication, which guarantees the smooth extrusion and homogeneity of slurries. The successful printing of SiC–Si slurries is not only related to proper viscosity, yield value, and shear thinning characteristics but it is also crucial for maintaining the homogeneity of slurries under extrusion pressure. Optimal SiC–Si slurries containing 52 vol % SiC–Si and 1.5 wt% HPMC exhibited proper viscosity, shear thinning, and homogeneity characteristics during printing. The obtained specimens achieved the best printing performance with height and section retention rates of 98.7% and 97.6%, respectively. When sintered at 1450 °C, Si3N4 fibres grow further and reach a diameter of 342.5 nm, the nitriding rate is 92.43%, the fibres tend to form a full network structure, and the mechanical properties of Si3N4-bonded SiC products are the best.

Towards net zero emissions, recovered silicon from recycling PV waste panels for silicon carbide crystal production

The high rate of PV adaptation around the world requires a strategy for recovery of the materials from PV waste panels and a circular market development. In particular, the silicon recovered from the PV cells can be used in different applications. A valuable acquisition is to refine the recovered silicon at metallurgical grade to a high level of purity namely electronic grade silicon which in conjunction with graphite can be the raw material for silicon carbide crystal production. Based on a comprehensive and critical review of the latest research and development of relevant technologies, a manufacturing process is proposed to increase the usage of renewable resources, reduce the energy consumption and CO2e emissions. The recovered silicon from recycling PV waste can reduce the CO2e emissions to a third of what is involved in the current carbothermic reduction of quartz in an induction furnace. Based upon the thorough evaluation of available evidence, a continuous coupled process is envisaged where the upgraded metallurgical grade silicon from recycling PV waste undergoes further vacuum and gas refining to the electronic grade silicon. Then the purified liquid silicon enters a vertical Bridgeman furnace for silicon carbide crystal production through a bottom seeded solution growth process. Considering the silicon melting point at 1410 °C, omitting a solidification/ meting step after vacuum/gas refining leads to energy and material saving. The continuous method can reduce the CO2e emissions up to 75% compared with the current silicon carbide production through Acheson process.

Synthesis and investigation of the physicochemical properties of polymorphic 3C–SiC

Silicon carbide (SiC) nanopowders were synthesized under Ar atmosphere via the carbonization reaction method using silicon powders and expanded graphite as initial materials, and ferric nitrate as catalyst precursor. The effects of heat treatment temperature and the C/Si molar ratio on SiC products were studied. The microstructure, phase composition and chemical state of the products were analyzed by XRD, SEM, XPS, TEM and Raman. The photoluminescence (PL) properties of SiC nanopowders were tested. The results showed that the content of the 3C–SiC product is higher after heat treatment at 1400 °C for 3 h with a molar ratio of C/Si of 1:1. 3C–SiC exists in the form of particles and wires. The formation process of 3C–SiC can be explained by a two-step method, nucleation under catalysis and growth under Vapor-Solid (VS) mechanism. Two ultraviolet light emission peaks are observed at about 318 and 380 nm. The main PL spectra of 3C–SiC nanopowders exhibit larger blueshifts. The blueshift is attributed to the stacking fault, oxygen defects, morphology and quantum confinement effect. It has potential application prospects in ultraviolet detectors, optoelectronic devices and light emitters.

Thermal Transformation of Secondary Resources of Carbon-Rich Wastes into Valuable Industrial Applications

Carbon-based materials have become an indispensable component in a myriad of domestic and industrial applications. Most of the carbon-based end-of-life products discussed in this review end up in landfills. Where recycling is available, it usually involves the production of lower-value products. The allotropic nature of carbon has been analysed to identify novel materials that could be obtained from used products, which also transform into a secondary carbon resource. Thermal transformation of carbon-rich wastes is a promising and viable pathway for adding value to waste that would otherwise go to landfills. The valorisation routes of four different carbon-rich wastes by thermal transformation are reviewed in the study—automotive shredder residue (ASR), textile wastes, leather wastes, and spent coffee grounds (SCGs). Textile wastes were thermally transformed into carbon fibres and activated carbon, while ASRs were used as a reductant to produce silicon carbide (SiC) from waste glass. The leather wastes and spent coffee grounds (SCGs) were employed as reductants in the reduction of hematite. This paper examines the possible routes of thermally transforming carbon-rich wastes into different industrial processes and applications. The transformation products were characterised using several techniques to assess their suitability for their respective applications. The strategy of valorising the wastes by thermal transformation has successfully prevented those wastes from ending up in landfills.

A general method for rapid synthesis of refractory carbides by low-pressure carbothermal shock reduction

Refractory carbides are attractive candidates for support materials in heterogeneous catalysis because of their high thermal, chemical, and mechanical stability. However, the industrial applications of refractory carbides, especially silicon carbide (SiC), are greatly hampered by their low surface area and harsh synthetic conditions, typically have a very limited surface area (<200 m2 g-1), and are prepared in a high-temperature environment (>1,400 °C) that lasts for several or even tens of hours. Based on Le Chatelier's principle, we theoretically proposed and experimentally verified that a low-pressure carbothermal reduction (CR) strategy was capable of synthesizing high-surface area SiC (569.9 m2 g-1) at a lower temperature and a faster rate (∼1,300 °C, 50 Pa, 30 s). Such high-surface area SiC possesses excellent thermal stability and antioxidant capacity since it maintained stability under a water-saturated airflow at 650 °C for 100 h. Furthermore, we demonstrated the feasibility of our strategy for scale-up production of high-surface area SiC (460.6 m2 g-1), with a yield larger than 12 g in one experiment, by virtue of an industrial viable vacuum sintering furnace. Importantly, our strategy is also applicable to the rapid synthesis of refractory metal carbides (NbC, Mo2C, TaC, WC) and even their emerging high-entropy carbides (VNbMoTaWC5, TiVNbTaWC5). Therefore, our low-pressure CR method provides an alternative strategy, not merely limited to temperature and time items, to regulate the synthesis and facilitate the upcoming industrial applications of carbide-based advanced functional materials.

Lightweight porous NiCo-SiC aerogel with synergistically dielectric and magnetic losses to enhance electromagnetic wave absorption performances

Microwave absorption performances can be remarkably enhanced using an electromagnetic (EM) wave absorber with synergistically dielectric and magnetic losses. In this study, the eggplant was used as a raw material to produce silicon carbide (SiC) aerogel by two steps: carbonization and subsequent carbothermic reduction. Then the magnetic NiCo layer was coated on the SiC aerogel (NiCo–SiC) by chemical plating method. The NiCo-SiC aerogel with an extremely low density (0.194 g/cm3) primarily composed of a porous SiC skeleton, SiC nanowires, and the magnetic NiCo alloy nanoparticles distributed on SiC skeleton and nanowires surfaces. The existence of magnetic NiCo alloy nanoparticles in the aerogel, the magnetic and dielectric losses are both increased by the formed heterogeneous interfaces. Thus, the NiCo–SiC aerogel with a thickness of 3 mm exhibits a minimum reflection loss (RLmin) of − 44.5 dB and an effective absorption bandwidth (RL<−10 dB) of 7.6 GHz, which displays the potential application in lightweight and excellent EM wave absorbers.

Glass waste derived silicon carbide synthesis via direct current atmospheric arc plasma

The paper presents the results of the experimental studies addressing the production of silicon carbide from glass waste by electric arc plasma processing. A feature of the method is the possibility of its implementation without the use of vacuum equipment. It is possible due to the effect of self-shielding of the reaction volume from atmospheric oxygen. This approach significantly simplifies the design of the electric arc reactor and its performance. After plasma processing of various types of glass waste (such as bottle glass, window glass, medical glass, quartz glass, parts of worn-out scientific and industrial equipment), silicon carbide based material was produced. Silicon carbide was obtained from a mixture of various glass waste at a current 200 A, where blend was first purified from unbound carbon and then was consolidated by spark plasma sintering at 1800 °C and 60 MPa pressure for 10 min. As a result, a ceramic bulk sample was fabricated from a mixture of glass waste of various origin. Such sample was characterized with hardness of 14.8 GPa, and attained density of 92.5 %. Despite a possible increase in the density due to impurities and inhomogeneities, the hardness of the fabricated sample is comparable to that of other silicon carbide based materials, including commercial ones. Since the hardness of the produced silicon carbide based material is comparable to that of commercial materials, the use of glass waste of various origin could be feasible for synthesis of silicon carbide based powders.

Finite element-based machine learning approach for optimization of process parameters to produce silicon carbide ceramic complex parts

Design and fabrication of silicon carbide ceramic complex parts introduce considerable difficulties during injection molding. Due to the great importance in processing optimization, an accurate prediction on the stress and displacement is required to obtain the desired final product. In this paper, a conceptual framework on combination of finite element method (FEM) and machine learning (ML) method was developed to optimize the injection molding process, which can be used to manufacture large-aperture silicon carbide mirror. The distribution characteristics of temperature field and stress field were extracted from FEM simulation to understand the injection molding process and construct database for ML modeling. To select the most appropriate model, the predictive performance of three ML models were estimated, including generalized regression neural network (GRNN), back propagation neural network (BPNN) and extreme learning machine (ELM). The results show that the developed ELM model exhibits exceptional predictive performance and can be utilized to predict the stress and displacement of the green body. This work allows us to obtain reasonable technique parameters with particular attention to the loading speed and provides some fundamental guidance for the fabrication of lightweight SiC ceramic optical mirror.

Study of the effect of the impurity composition of silicon on the defectiveness of reaction-bonded silicon carbide samples

Large-sized complex-shaped silicon carbide products can be obtained via liquid silicon infiltration, however, the presence of free silicon in their composition limits the scope of their application. The silicon content can be reduced by forming a fine-grained porous structure of the material and control of the growth rate of the carbide layer on the pore walls during liquid-phase silicification. We present the results of studying the effect of the impurity composition of silicon grade KR00 on the appearance of defects in the structure of fine-grained reaction-bonded silicon infiltrated silicon carbide (The results obtained can be used in the production of tribotechnical parts, valves, etc. on the basis of RGCC.). It is shown that iron contained in industrial silicon KR00 exerted the greatest effect. At a content of Fe below 0.94 %wt., SiSiC samples are almost defect-free with the density not less than 3.00 ± 0.05 g/cm3. At a Fe content of 1.49 %wt., defects in SiSiC samples are observed in the form of under-impregnated regions, which are probably attributed to the increased solubility of carbon in the silicon melt upon impregnation with technical silicon with an increased iron content and, as a consequence, more intensive growth of the silicon carbide layer on the pore walls with their subsequent overlapping. As the melt moves deeper into the carbonized porous sample, it becomes depleted in silicon with an increase in the content of impurities, primarily Fe and Al, and the formation of SiC, Fe3C, and FeSi. The theoretical calculation showed that the relative changes in volume for the reactions of SiC and Fe3C formation upon interaction of 1 mole of carbon with silicon and iron are 134 and 339%, respectively. Moreover, with a significant content of iron in the melt, a significant role in the overlap of capillaries can be played by the volumetric change associated with the formation of Fe3C. The results obtained can be used in the production of SiSiC-based tribotechnical parts, valves, etc.

In-situ resource utilization: ferrosilicon and SiC production from BP-1 lunar regolith simulant via carbothermal reduction

A study of carbothermal reductive smelting of the BP-1 lunar simulant, aiming to the in-situ production of ferrosilicon and silicon carbide is reported in the present study. BP-1 simulates a low Ti-content mare regolith and is mined in Arizona. The process was first studied from a thermodynamic point of view, while the final ferrosilicon product was examined metallographically. Reduction experiments were performed, after the enrichment of the simulant in iron oxide through dry magnetic separation, under vacuum. Thermodynamic analysis indicates that the production of a ferrosilicon alloy in smelted form and SiC is possible over 1200 °C. The use of carbon amounts in excess does not have significant effects on the progress of the reduction reaction at 1300 °C. The experimental results showed that reduction at gentle temperature conditions (1300 °C) advances the formation of a granulated ferrosilicon alloy potentially appropriate as a feed for 3D printing. X-ray diffractometry and scanning electron microscopy showed that the synthesized ferrosilicon alloy is a homogeneous metallographic structure but having a high silicon content (average concentration 23.78% by weight) and minor contents of aluminum and titanium (1.80% and 0.94% by weight, respectively). This resulting alloy could be used in various basic lunar building structures such as dwellings and research facilities, as well as to produce the machinery required for mining the ore. The second by-product of the reaction, silicon carbide, can be used as a filler in polypropylene resin/SiC composite that has been proposed as a suitable material for shielding space radiation.