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Binder jetting requires the sintering of green parts to reach the properties of a metallic component. The sintering activity and sintered material properties of stainless steels are sensitive to powder oxidation and binder contamination, which are introduced by improper debinding. Air is often used during thermal debinding as oxygen aids binder removal, but the metal powder is oxidised being detrimental to sintering densification and final material properties. Hence, the impact of decreasing oxygen content in the debinding atmosphere on the sintering of 17-4 PH at 1300°C for 2 h in an inert argon atmosphere was investigated. Debinding in oxygen-containing atmospheres revealed the presence of δ-ferrite in the sintered microstructure, enhancing densification during sintering. Debinding in an inert Ar atmosphere resulted in low densification that was correlated to the absence of δ-ferrite due to the high amount of carbon in the sintered part. The high carbon content after debinding in Ar resulted in nearly complete oxygen removal by carbothermal reduction during sintering. Debinding in Ar + 1 vol.% O2 achieved the best combination of reducing final oxygen content by 46% via carbothermal reduction and the absence of carbon pickup during debinding and sintering. Debinding in processing atmospheres containing 3 vol.% O2 up to 20 vol.% O2, in contrast, led to a significant oxygen increase of 53 to 74% after sintering compared to the virgin powder. [ABSTRACT FROM AUTHOR]

A dual phase high‐entropy (Hf,Nb,Ta,Ti,Zr)C–(Hf,Nb,Ta,Ti,Zr)B2 ultra‐high temperature ceramic was synthesized using a single step boro‐carbothermal reduction route. The synthesized powder was densified by spark plasma sintering at 2000°C, resulting in complete solid solution formation and a relative density of ≈99%. The dual phase ceramic was 43 vol% high‐entropy carbide and 57 vol% high‐entropy boride. The grain sizes were 0.85 ± 0.34 µm for the carbide and 0.87 ± 0.33 µm for the boride with minimal residual oxide (0.2 vol%) detected in the microstructure. The resulting composition had a higher microhardness than the individual boride and carbide ceramics across the range of testing loads with maximum hardness of 47.5 ± 4 GPa at a load of 0.49N. The high hardness is attributed to the minimum residual oxide, submicron grains, favorable carbide‐to‐boride ratio, homogeneous metal distribution within the phases, uniform microstructure, and synergistic dual phase hardening. [ABSTRACT FROM AUTHOR]

Boron nitride (BN) powders with near‐spherical particles of more than 10 µm were synthesized by templated carbothermal reduction and nitridation. The effects of processing factors, such as raw material mixing methods, C/B2O3 molar ratios, and carbon templates, were systematically studied, and the reaction mechanism was discussed. The experimental results showed that the integrity and morphology of the carbon templates was usually destroyed during ball milling or grinding, but preserved during magnetic stirring. The morphology of synthesized BN particles depended on the C/B2O3 molar ratio in starting reactant mixtures and gradually changed from sheet‐like to near‐spherical shape with decreasing C/B2O3 molar ratio. The morphology and size of synthesized BN particles agreed with that of the carbon templates, which means that the morphology and size of synthesized BN particles can be tailored by controlling that of the carbon template. The BN near‐spherical particles synthesized in this work may be used as thermally conductive fillers for electronic packaging. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Extractive Metallurgy) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Retired wind turbine blades (RWTBs) mainly consist of glass fibers and resins, which have abundant of carbon and silicon resources. This study synthesized SiC nanowires (SiC NWs) by using the RWTBs for the first time. The RWTBs were grinded into powders and pyrolyzed at 600 °C for 2 h, the pyrolysis solid residues (P-RWTBs) mixed with apricot shell char (ASC) and silicon powder in a stoichiometric ratio (C/Si = 4), and then the mixture calcined at 1550 °C for 4 h in an argon atmosphere. XRD, FTIR and XPS results indicating that SiC NWs had been successfully synthesized. SEM and TEM micrographs show that the produced SiC NWs exhibit a worm-like shape, with diameters of 50–100 nm, and interweave into a 3D network body. The minimum reflection loss (RL min) of the SiC NWs 3D network body reached −18.17 dB at the thickness of 4.8 mm, which meet the requirements of microwave-absorbing materials. Its good microwave-absorption property is due to the various loss types of the electromagnetic waves that caused by the special structure. This study provides a new approach for high-value utilization of the RWTBs, which is of great significance in realizing the "green retirement" of glass fiber reinforced polymers. [ABSTRACT FROM AUTHOR]

In this research, AlN nano-powders were prepared by combining carbon-containing droplet combustion (CCDC) and carbothermal reduction (CR) methods. Firstly, Al 2 O 3 +C mixed precursor was synthesized by the CCDC method, and then AlN nano-powder was obtained by the carbothermal reduction of this CCDC precursor. The effects of urea and glucose contents, ignition temperature, and combustion atmosphere on precursors and AlN powders were studied in detail. The results showed that with the molar ratio of urea to aluminum nitrate (U/A) of 3, the atomic ratio of carbon to aluminum (C/Al) of 6, and the ignition temperature at 800 °C under air atmosphere, the prepared precursor was composed of hollow and spherical structure particles exhibiting rough and porous surface morphology with high specific surface area (SSA) (41.4 m2/g). AlN nano-powders obtained by the carbothermal reduction of this precursor were found to be consisted of fine particles with the size of 20–30 nm with high SSA of 39.9 m2/g. [ABSTRACT FROM AUTHOR]

The reaction mechanism of TiB2 synthesized by carbothermal reduction is unclear due to a lack of thermodynamic research. In this work, the phase diagrams of TiO2-B2O3-C system were analyzed at a large temperature range (900–1800 °C), illustrating that Ti4O7, Ti3O5, and TiC were the main intermediate products. According to the Gibbs free energy minimum principle, the synthesis pathways of the main intermediate products and the target product TiB2 were discussed, respectively. Based on the thermodynamic research, the reaction mechanism of TiO2-B2O3-C system was proposed and verified by experimental research at 900–1500 °C. X-ray-pure TiB2 powder was synthesized at 1500 °C for 30 min and the possible reaction mechanism could be divided into three stages: TiO2(anatase)→TiO2(rutile)→Ti3O5, TiC →TiB2. [ABSTRACT FROM AUTHOR]

Recovery of critical metals such as Li and Co from the spent lithium-ion batteries is necessary to alleviate resource scarcity and mitigate supply risk. The present study emphasizes the carbothermal and hydrogen reduction of lithium cobalt oxide (LCO) and the recovery of Li and Co from spent LCO-based batteries. Carbothermal reduction (CR) and hydrogen reduction (HR) at 500–900 °C followed by water leaching was carried out for Li recovery. Complete reduction with hydrogen was achieved at 500 °C, whereas a significant reduction for CR was achieved at 700 ℃. Characterization analysis of the reduced products affirms the decomposition of the layered LCO structure with the evolution of new phases. CR favored the Li2CO3 formation, while the LiOH phase was observed in the HR products. Both reductive treatments yielded metallic Co, but CoO was also found in the CR products. The hydrogen reduction was found better compared to carbothermal reduction for both Li and Co recovery. CR process at 900 °C resulted in 61% Li dissolution and 76.5% Co recovery, while HR at 500 °C yielded much higher Li dissolution (93%) and Co recovery (86.5%). [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To identify the mineral grade ore, two distinct Malaysian ilmenite ores (FeTiO3) from different placers deposits were examined. The sources of ilmenite ore were the Kinta Valley in Perak and the Langkawi Black Sand Beach in Kedah. Both of the ores were reduced by palm char as a sustainable carbon reductant. The study examined carbon characteristics and phase transitions following carbothermal reduction at 1550°C. Prior to the studies, the reductant palm char was characterized by XRF, BET surface area measurement, SEM, and ultimate with proximate analyses. It is shown that the palm char had low moisture (4.10 wt.%) and high fixed carbon (75.40 wt.%). The high carbon content, volatile matter, and porous structure of palm char played a significant role in the gas generated during the carbothermal reduction of ilmenite ores. Carbothermal reduction of both ilmenite ores with palm char-produced rutile, iron, titanium carbide, and pseudobrookite. The XRF analysis exhibits the existence of 18.41 and 35.76 wt.% of Fe and TiO2 respectively in Perak ilmenite ore. While Langkawi ilmenite ore shows 9.28 and 22.72 wt.% of Fe and TiO2 respectively.

The development of high‐temperature electromagnetic (EM) wave absorbing materials is an important direction for achieving radar stealth in high‐speed aircraft. In this study, HfC–SiCf composite ceramics with 3D reticular structure were synthesized in one‐step using the molten‐salt‐assisted carbon thermal reduction method. During the synthesis process, SiC grew in situ into a fibrous structure with a diameter of 500 nm and lengths ranging from 2 to 30 µm. By adjusting the molar ratio of HfC to SiC, the HfC‐30 mol% SiC (HS30) exhibited the best EM absorption performance at room temperature, with a minimum reflection loss (RLmin) of −31.4 dB at 16.1 GHz and an effective absorption bandwidth (EAB) of 4.6 GHz. The excellent absorption performance was attributed to the 3D reticular structure composed of SiC fibers, HfC bulk, and HfC nanoparticles, which significantly increased the number of pores and heterogeneous interfaces in the material. These microinterfaces induced interface polarization effects, thereby effectively enhancing the EM absorption. As the temperature increased, the EM absorption performance declined. At 900°C, the HS30 sample exhibited an EAB of 1.18 GHz from 12.4 to 13.58 GHz and an RLmin of −$ - $22.6 dB at 13.0 GHz. This research provides references for understanding the effects of material composition and structure on EM absorption performance. [ABSTRACT FROM AUTHOR]

Sluggish redox kinetics and severe polysulfide shuttling are major hurdles for the commercialization of lithium–sulfur (Li–S) batteries. Transition‐metal compound catalysts offer a promising solution by providing excellent polysulfide adsorption capabilities, outstanding catalytic activities, and homogeneous nucleation control of Li2S2/Li2S. The electronic structure of transition‐metal sites in catalysts can also be fine‐tuned through bi‐metallic coupling, which can further improve the catalytic activities. In this study, bi‐metallic nickel molybdenum phosphide is co‐synthesized with Li2S and carbon through a carbothermal reduction process, forming a cathode composite (Li2S @ NixMoyPz @ C). This process is not only advantageous for large‐scale manufacturing due to its simplicity, but also ensures homogeneous integration and distribution of the catalyst within the cathode composite. Furthermore, applying Li2S as an active material allows the creation of an anode‐free cell configuration, enhancing the overall cell energy density. The anode‐free cell with the Li2S @ NixMoyPz @ C composite cathode demonstrates an outstanding capacity retention of 50% over 300 cycles at a negative‐to‐positive capacity (N/P) ratio of 1. Additionally, the bi‐metallic phosphide integrated Li2S cathode composite delivers a remarkable anode‐free pouch cell performance of 703 mA h g−1 (on Li2S basis) under the challenging conditions of an E/Li2S ratio of 4.5. [ABSTRACT FROM AUTHOR]

Nano tungsten carbide (WC) was synthesized using loose yellow tungsten oxide (WO3) rods, which were derived from violet tungsten oxide (WO2.72) through calcination in dry oxygen. The WO3 rods were then subjected to ball milling with carbon black, followed by carbothermal reduction and carbonization. Unlike conventional methods such as hydrogen reduction or carbothermal reduction, this technique avoids the formation of hydrated tungsten oxides and addresses challenges related to precise carbon control and matching. This streamlined procedure produces nanoscale tungsten carbide particles approximately 150 nm in size, showing great potential for future industrial applications. [ABSTRACT FROM AUTHOR]

As a kind of ultra-high temperature ceramic, TaC is widely used in aerospace field. In order to improve its high temperature oxidation resistance, SiC is usually added as a second phase. TaC-SiC nanocomposites prepared by precursor-derived ceramic method have the advantages of low pyrolysis temperature, small particle size and uniform phase composition. Some studies have used solid polycarbosilane (PCS) as the precursor of SiC. However, it has problems such as high cost and need to add solvent. In this work, TaC-SiC nanocomposites were prepared by precursor-derived ceramic method with polytantaloxane (PTO) and vinyl-containing liquid polycarbosilane (LPVCS) instead of PCS as raw materials after 2 h pyrolysis at 1600 °C. The obtained TaC-SiC nanocomposites have a particle size of about 200 nm and a grain size of 15–40 nm, wrapped by 1–2 nm amorphous carbon shells, which is beneficial to inhibit grain growth. By analyzing the oxidation mechanism of TaC-SiC nanocomposites, it was found that higher SiC content was conducive to antioxidant, because the SiO 2 protective layer formed by oxidation insulated O 2 diffusion. [ABSTRACT FROM AUTHOR]

The current method for recovering iron oxide scale in the steel industry is not economically optimal, especially for high‐alloy scales found in alloyed steel. This study focuses on iron oxide scale containing valuable metals like chromium (Cr), molybdenum (Mo), and vanadium (V). The required carbon addition is calculated based on the iron and chromium oxides in the scale. The effects of varying carbon additions and reduction temperatures on reduction efficiency are thoroughly examined. Kinetic studies show that as temperature and carbon increase, the rate‐limiting step shifts from interfacial diffusion to interfacial reaction. Reduction experiments assess carbon utilization, metallization rate, deoxidation rate, and removal of harmful elements. Results show that high temperatures hinder sulfur (S) and phosphorus (P) removal, and excess carbon reduces carbon utilization efficiency. Optimal conditions are a carbon ratio of 0.2174 and a temperature of 1150 °C. The carbothermic reduction product requires further refinement through conventional ladle slag systems to meet the quality standards for metallic materials. Over 65% of alloying elements are recovered, though phosphorus content remains slightly higher than in finished alloy steel. The materials from this study are suitable as high‐quality intermediates for alloy steel production. [ABSTRACT FROM AUTHOR]

Si3N4 ceramics with improved thermal conductivity and mechanical properties were prepared by carbothermal reduction and two‐step sintering. The addition of 2 wt% C led to the development of an intergranular phase YNSiO2 with reduced oxygen content. Notably, setting the pre‐sintering temperature at 1450°C promoted the formation of a rough bimodal morphology within the Si3N4 ceramics. Furthermore, an extended holding period at 1850°C resulted in additional grain growth and the elimination of intergranular phases. The Si3N4 specimens produced at 1450°C for 3 h followed by 1850°C for 8 h, incorporating 2 wt% C, exhibited a notable continuity between Si3N4 grains. The thickness of the grain boundary layer was only about 1 nm, and the N/O atomic ratio of the intergranular phase was measured to be 0.42. Consequently, the resulting thermal conductivity, flexural strength, and fracture toughness of Si3N4 specimens were found to be 101 W·m−1·K−1, 712 ± 29 MPa, and 7.7 ± 0.2 MPa·m1/2, respectively. Compared with samples without C additive and directly sintered at 1850°C for 8 h, the Si3N4 specimens produced in this work showed a significant increase of more than 50% in thermal conductivity and about 17% in fracture toughness. [ABSTRACT FROM AUTHOR]

To identify the mineral grade ore, two distinct Malaysian ilmenite ores (FeTiO3) from different placers deposits were examined. The sources of ilmenite ore were the Kinta Valley in Perak and the Langkawi Black Sand Beach in Kedah. Both of the ores were reduced by palm char as a sustainable carbon reductant. The study examined carbon characteristics and phase transitions following carbothermal reduction at 1550°C. Prior to the studies, the reductant palm char was characterized by XRF, BET surface area measurement, SEM, and ultimate with proximate analyses. It is shown that the palm char had low moisture (4.10 wt.%) and high fixed carbon (75.40 wt.%). The high carbon content, volatile matter, and porous structure of palm char played a significant role in the gas generated during the carbothermal reduction of ilmenite ores. Carbothermal reduction of both ilmenite ores with palm char- produced rutile, iron, titanium carbide, and pseudobrookite. The XRF analysis exhibits the existence of 18.41 and 35.76 wt.% of Fe and TiO2 respectively in Perak ilmenite ore. While Langkawi ilmenite ore shows 9.28 and 22.72 wt.% of Fe and TiO2 respectively. [ABSTRACT FROM AUTHOR]

A heterostructure based on MOFs with a small lattice mismatch is ideal for improving glucose's electrochemical sensing performance. Herein, a novel one‐pot carbothermal reduction technique to prepare Cu‐BTC@Cu/C heterostructure with intimate interfacial contact and high yield was developed, by in situ integrating Cu‐BTC (Cu3(BTC)2 ⋅ 3H2O) and its derived Cu/C nanocomposites. Structure characterizations demonstrated that Cu‐BTC@Cu/C heterostructure shows a synergistic effect in the combination of these two components, with more electrochemical active sites and lower resistance. Compared with each individual component, Cu‐BTC@Cu/C heterostructure exhibits better glucose electrooxidation performance. Under optimal condition, an extremely sensitive nonenzymatic glucose sensor with a low detection limit of 6.78 μM, sensitivity of 911.03 μA mM−1 cm−2, linear range of 0.001–2.0 mM, and anti‐interference performance is presented. Meanwhile, the newly constructed sensor was effectively employed for detecting glucose in honey sample with perfect recoveries, showing its great potential toward glucose monitoring in real sample. In addition, it has been demonstrated Cu(II) can be induced into Cu(I) by glucose in solution, while Cu(I) could be electrochemically converted to Cu(II), therefore achieving a Cu(I)/Cu(II) redox cycle. It offers a promising strategy for synthesis of advanced electrocatalysts with high efficiency and promising applications in this paper. [ABSTRACT FROM AUTHOR]

A hydrothermal method was employed to synthesize the precursor of nano-zirconium carbide, which was subsequently heat treated at high temperatures under vacuum to obtain finely dispersed nanometer-sized zirconium carbide powder through a carbothermic reduction reaction. Scanning Electron Microscopy (SEM) was utilized to examine the microstructure of the precursors obtained under different hydrothermal conditions and carbon contents. The effects of different heat treatment temperatures on the microstructure of the products were analyzed. Transmission Electron Microscopy (TEM) confirmed the boundary coating structure of the hydrothermal precursor and provided insights into the phase structure of the nanometer-sized zirconium carbide. The reaction mechanism and temperature involved in the carbothermic reaction process were determined through calculations. Furthermore, the energy, phase and microstructure of the reaction were investigated using Thermogravimetric Analysis (TG-DSC) and X-ray Diffraction (XRD) at different temperatures. The obtained results revealed that the zirconium carbide precursor was synthesized via the hydrothermal method exhibited a core-shell structure with a boundary coating, which not only ensured uniform contact between C and ZrO 2 particles but also facilitated the formation of zirconium carbide. The results show that the most suitable process parameters are Zr/C 1: 7, 240 °C and 24 h. The thermodynamic calculation results show that ZrO 2 combines with carbon to form CO and ZrC when the temperature reaches 1656.56 °C. As the temperature rises, CO reacts with ZrO 2 to form ZrC and CO 2. TG-DSC shows that the carbothermal reduction reaction starts at 1100 °C and reaches its peak at 1418 °C. XRD analysis confirms that when the temperature reached 1450 °C ZrC appeared. At 1600 °C, the phase transition of ZrC is basically completed. TEM images showed that the synthesized zirconium carbide particles were about 30 nm. [ABSTRACT FROM AUTHOR]

A dense, fine‐grained, and toughened nonstoichiometry high entropy carbide (HEC) (MoNbTaTiW)C4.5 was synthesized via a two‐step way of carbothermal reduction‐solid solution using metal oxides and carbon. The effects of carbothermal reduction temperature, sintering temperature, and carbon content on the phase, microstructure, mechanical and thermal properties of (MoNbTaTiW)C4.5 were studied. The results showed dense and single phase (MoNbTaTiW)C4.5 were synthesized through reduction of metal oxides at 1600°C and sintered at and above 1950°C by spark plasma sintering. Reduced carbon content and higher solid solution temperature were beneficial to obtain dense HECs with better mechanical properties. With a carbon content of 90%, a reduction temperature of 1600°C, a holding time of 20 min, and a sintering temperature of 1950°C, the as‐synthesized (MoNbTaTiW)C4.5 showed a higher fracture toughness (5.2 MPa·m1/2). Besides, the (MoNbTaTiW)C4.5 showed a low thermal conductivity (5.9 W/m·K, at room temperature). [ABSTRACT FROM AUTHOR]

The article analyses the thermodynamic laws of processing iron-based compounds contained in copper production slag using the method of carbothermic recovery. Evaluation of the probable direction of carbothermic reactions occurring between oxidized compounds and carbon in the slag was carried out by changing the thermodynamic values of the system. In the thermodynamic scientific justification of the physic-chemical processes occurring in the carbothermic recovery of metal oxides in slag, the change of Gibbs energy of the system with temperature increases and the estimation of equilibrium constants of chemical reactions based on Gibbs energy and the method of determining the slowest (limiting) chemical process among them were used. The Microsoft Excel program was used to determine the thermodynamic values of the chemical reactions occurring in the slag and reducing agent system and to compile their Ellingham graphs. [ABSTRACT FROM AUTHOR]

This article investigated the recoverability of the Ga in bauxite by carbothermal reduction. Currently, Ga is mostly manufactured from bauxite through the Bayer process as a by-product of alumina, but it is worthwhile to consider alternative processes under stricter environmental regulations and a shortage of high-quality bauxite. This study focused on the Pedersen process, which is the alumina production process consisting of carbothermal reduction and alkaline leaching. The metal and slag phases were prepared by carbothermal reduction of bauxite at 1873 K, and then aluminium in the slag was leached with (Na2CO3 + NaOH) solution at 348 K. Evaluation by inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry revealed that almost all Ga in bauxite was transferred to the metal phase, and the distribution to the slag phase was negligible in carbothermal reduction, which agrees with the thermodynamic consideration. These results suggest that the gallium recovery from pig iron is necessary to produce Ga in the Pedersen process. [ABSTRACT FROM AUTHOR]

The decarbonisation of the steel and cement industry is of utmost importance in tackling climate change. Hence, steel production in modern integrated steel mills will be shifted towards electric arc furnaces in the future, in turn causing dwindling supplies of blast furnace slag, which is used as a supplementary cementitious material inter alia to reduce the CO2 emissions of cement production. Achieving a sustainable circular steel and building material economy requires the valorisation of currently landfilled steel slags and investigating utilisation options for electric arc furnace slag, which is increasingly being generated. For this purpose, different metallurgical residues and by-products were treated by carbothermal reduction in an inductively heated graphite crucible and then rapidly cooled by wet granulation, yielding a slag fraction similar to granulated blast furnace slag and a metal fraction valuable as a secondary raw material. A spreadsheet-based model was developed to calculate residue combinations to accomplish target compositions of the slag and metal fractions to fulfil previously identified requirements of the targeted cementitious and ferrous products. The results demonstrate the high accuracy of the model in predicting the properties (e.g. main oxide composition) of the generated slag and metal fraction, which fulfil the needed requirements for their use as (i) a supplementary cementitious material and (ii) a secondary raw material in steel production. [ABSTRACT FROM AUTHOR]

A dense, fine‐grained, and toughened nonstoichiometry high entropy carbide (HEC) (MoNbTaTiW)C4.5 was synthesized via a two‐step way of carbothermal reduction‐solid solution using metal oxides and carbon. The effects of carbothermal reduction temperature, sintering temperature, and carbon content on the phase, microstructure, mechanical and thermal properties of (MoNbTaTiW)C4.5 were studied. The results showed dense and single phase (MoNbTaTiW)C4.5 were synthesized through reduction of metal oxides at 1600°C and sintered at and above 1950°C by spark plasma sintering. Reduced carbon content and higher solid solution temperature were beneficial to obtain dense HECs with better mechanical properties. With a carbon content of 90%, a reduction temperature of 1600°C, a holding time of 20 min, and a sintering temperature of 1950°C, the as‐synthesized (MoNbTaTiW)C4.5 showed a higher fracture toughness (5.2 MPa·m1/2). Besides, the (MoNbTaTiW)C4.5 showed a low thermal conductivity (5.9 W/m·K, at room temperature). [ABSTRACT FROM AUTHOR]

Carbonaceous materials suffer from low capacity when applied as an anode in sodium-ion batteries. Constructing metal sulfides/carbon composites can address the above issue but leads to limited cycle stability and sluggish kinetics. In the current work, ultrasmall PbS nanocubes embedded in a carbon framework (named PbSnc@C) are synthesized by combining emulsion polymerization, electrostatic interaction promoted adsorption, and in situ carbothermal reduction. PbSnc@C has a uniform spherical morphology and well-developed pore structure, with 20 nm PbS cubes dispersed in the carbon framework. As such, it displays a fast Na+ transfer rate, shortened Na+ diffusion radius, and optimal structural merits to alleviate the volume change during the sodiation/desodiation process. When employed as a sodium-ion battery anode, PbSnc@C demonstrates a large capacity of 332 mAh g-1 at 0.1 A g-1, superior rate capability with a remarkable capacity of 145 mAh g-1 at 20 A g-1, and good electrochemical stability during a 2000-cycle repeated charge/discharge process. Moreover, the in-depth study indicates that the Na+ storage in PbSnc@C follows a two-step mechanism: (i) the conversion reaction between PbS and Na+, leading to the formation of Pb metal and Na2S, and (ii) an alloying of Pb and Na+. [ABSTRACT FROM AUTHOR]

In this article, a novel method for SiC production from a residue of coal fly ash (CFA) after high-pressure leaching with a mixture of NH 4 HSO 4 + H 2 SO 4 is proposed. A thermodynamic analysis showed that SiC can be obtained at >1500 °C, and titanium carbide (TiC) and ferrosilicon (FeSi) can form as byproducts. Carbothermal reduction of the CFA residue with carbon in the range 1300–1500 °C with holding time 1–3 h was investigated. X-ray phase analysis (XRD) indicated that SiC forms at >1425 °C. Iron compounds in the form of Fe 3 Si and Fe 5 Si 3 were detected by Mössbauer spectroscopy in a sample sintered at 1500 °C. The possibility of SiC production by a two-step procedure was demonstrated. First, a SiC powder was obtained from the CFA residue and carbon at 1500 °C, then SiC was mixed with yttrium aluminum garnet Y 3 Al 5 O 12 and processed by spark plasma sintering at 1750–2000 °C, holding time 5 min, and pressure 50 MPa. Ceramic samples obtained at 1850 and 1900 °C with compressive strength of 350 ± 17.5 & 416 ± 20.8 MPa and Vickers hardness of 17.89 ± 0.89 & 15.97 ± 0.79 GPa, respectively, proved to be comparable to the best reported SiC + yttrium aluminum garnet ceramics. Thus, this study presents an original method for ceramics production from solid waste of coal-fired power plants; this approach will allow to create a comprehensive technology for utilizing 100 % of CFA. [ABSTRACT FROM AUTHOR]

Mimicking nature is an effective strategy for designing high performance materials. However, artificially constructing biomimetic materials with complex hierarchical structures remains a great challenge. Herein, a biomimetic, anisotropic, robust, thermoconductive, and high temperature-resistant porous SiC ceramic is reported to be used as a high temperature filter. The unidirectional pore channel structure of poplar wood is accurately inherited in biomorphic SiC ceramic by an in-situ carbothermal reduction reaction between wood-derived carbon precursors and SiO vapor generated from SiO particles. Due to the anisotropic architecture with vertically aligned and densely interconnected pore channels, the light-weight and high purity biomorphic SiC ceramic exhibits an excellent flexural strength of 41.63 MPa at ∼78.6% porosity, a high thermal conductivity of 10.50 W m−1 K−1 with ∼77.6% porosity, an anisotropic thermal conductivity factor of 5.79, and good thermal stability at ∼900 °C. Meanwhile, it demonstrates a high gas permeability (k 1 = 11.83 × 10−12 m2, k 2 = 1.86 × 10−6 m) with ∼81.9% porosity and a good filtration efficiency of 89.81% for PM > 2.5 μm under an extremely low pressure drop (0.69 kPa). These results indicate that this approach could open a new avenue for the design and preparation of high performance porous ceramics suitable as filters in high temperature environments. [ABSTRACT FROM AUTHOR]