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A novel (MoCrVMn) 2 FeB 2 based high-entropy cermets were prepared by two-steps method and the microstructure and mechanical properties were investigated. The single-phase (MoCrVMn) 2 FeB 2 powders were synthesized at 1400 °C for 2 h, and subsequently the (MoCrVMn) 2 FeB 2 based high-entropy cermets were prepared via pressureless sintering technique. The results revealed that the phase evolution was as follows: (Mo, Cr, V, Mn, Fe, B) → (Fe 2 B, V 2 B 3 , MoB) → ((FeVMn) 2 B, (FeVMnCr) 2 B, Mo 2 FeB 2) → (MoCrVMn) 2 FeB 2. The (MoCrVMn) 2 FeB 2 based high-entropy cermets sintered at 1250 °C showed good denseness and the ceramic phases were uniformly distributed in the metal bond, with the optimal mechanical properties of hardness 1355 HV 30 and fracture toughness 19.09 MPa m1/2. With the increase of temperature, the hardness increased first and then decreased, and the fracture toughness was basically unchanged first and then increased, and then decreased. This study provides a new route to further optimize the performance of Mo 2 FeB 2 based cermets. [ABSTRACT FROM AUTHOR]

The controllable α/β ratio of Si 3 N 4 powder was synthesized using tetraethyl orthosilicate (TEOS), glucose, MgCl 2 and YCl 3 ·6H 2 O by sol-gel assisted carbothermal reduction and nitridation (CRN). This study aimed to investigate the impact of various parameters, including a H 2 O/TEOS mol ratio of the sol, a C/Si mol ratio, sintering aids, and the temperature of CRN on the phase transformation of α-Si 3 N 4. The results demonstrated that the H 2 O/TEOS ratio significantly influenced the relative content of α and β phase in Si 3 N 4 by changing the morphological characteristics of SiO 2. When the H 2 O/TEOS ratio was 100, β-Si 3 N 4 powder with an approximate β content over 88 wt% was synthesized at 1500 °C. This remarkable phase transformation was likely facilitated by the eutectic liquid phase consisting of MgSiO 3 /Mg 2 SiO 4. The SEM image revealed rod-like whiskers with a length around 1.4 μm for the β-Si 3 N 4 grains. Due to the presence of liquid phase, the synthesis of spherical-like α-Si 3 N 4 nano-powder with an α-phase content of 91 wt% was achieved at a lower temperature of 1450 °C, with an H 2 O/TEOS ratio of 15 and a C/Si ratio of 4. The size of the particles was about 70 nm due to the reduced reaction temperature. Furthermore, without the addition of any sintering aids or Si 3 N 4 seeds, high purity α-Si 3 N 4 with an α phase content approaching 96 wt% could be synthesized at 1500 °C, using an H 2 O/TEOS ratio of 15 and a C/Si ratio of 4. The resulting α-Si 3 N 4 powder exhibited an extremely regular hexagonal prism shape with a length of approximately 2 μm. [Display omitted] [ABSTRACT FROM AUTHOR]

As one of the main waste streams of the manufacturing process of solid oxide cells (SOCs), scrap half-cells - discarded before the deposition of the barrier layer and the air electrode - imply the loss of significant quantities of ceramic composite material containing critical and hazardous elements, namely yttria-stabilized zirconia (YSZ) and NiO. These materials represent more than 90 wt% of an entire anode-supported cell. In this contribution, scrap half-cells were fragmented and subjected to three subsequent milling and sieving (below 25 μm) steps to recover composite NiO-YSZ powders with the appropriate specifications for reuse in SOC manufacturing. The overall characterization in terms of specific surface area, particle size distribution and crystalline phase retention confirmed the suitability of the recovered powders. Half-cells were manufactured including 30 wt% of recovered NiO-YSZ composite powders in their fuel electrode support, produced via tape-casting in combination with 70 wt% of virgin materials. The obtained cells were morphologically, mechanically and electrochemically tested and compared against standard cells constituted by 100 wt% of virgin materials. The electrochemical characterization highlighted 0.68 A cm−2 for the standard and recycled cells, at 600 °C and 0.7 V, while at 650 °C and same voltage both cells measured 1.12 A cm−2. This demonstrates the feasibility of recovering scrap SOCs through the presented method. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the structural, magnetic, and blood compatibility properties of Sr2+ substituted for Cu2+ in Cu 1−x Sr x Fe 2 O 4 (x = 0.0 to 1 with a 0.25 increment) nanoparticles synthesized via the sol-gel auto-combustion technique. Regardless of the substitution rate, the sol-gel auto-combustion method consistently yields powders with sizes ranging from 20 to 40 nm. The specific surface area of the produced powders is determined as 12 m2/g. X-ray diffraction analysis reveals that CuFe 2 O 4 exhibits a singular phase; however, as the Sr2+ ion substitution increases, the emergence of various secondary phases becomes apparent, with their proportions increasing with the substitution rate. The magnetic characteristics of the synthesized powders exhibit variations in magnetization, correlating with the distribution of cations in the sublattice points. Coercivities are influenced by both anisotropy and secondary phases. Saturation magnetization decreases from 31.3 (CuFe 2 O 4) to 7.6 (SrFe 2 O 4) emu/g with Sr replacement. The lowest observed coercivity is 429.5 Oe in powders prepared with CuFe 2 O 4 composition, while the highest is measured at 583.8 Oe in nanopowders prepared with Cu 0.5 Sr 0.5 Fe 2 O 4 composition. Moreover, blood compatibility experiments indicate significantly low hemolysis ratios for Cu 1−x Sr x Fe 2 O 4 nanoparticles. Additionally, all examined samples exhibit an increase in Soret band intensity compared to the negative control test, suggesting potential biocompatibility. [ABSTRACT FROM AUTHOR]

Currently, the lattice oxygen is the key factor affecting the thermal conductivity of AlN ceramics. In this paper, three methods are proposed to limit lattice oxygen, namely reducing the original powder oxygen content, changing the debinding atmosphere, and extending the sintering time. The results show that the low powder oxygen content and protective debinding atmosphere alter the carbon and oxygen content, and further promote the formation of the Y 4 Al 2 O 9 (YAM) phase. The generated YAM phase can effectively reduce the lattice oxygen in terms of thermodynamics. Prolonged high temperatures can provide kinetic conditions to reduce the lattice oxygen to 0.0343 wt%. In addition, morphological changes of the phase at the grain edges and their influence on the mechanical properties were noted. Finally, AlN ceramics with a thermal conductivity of 220 W m−1 K−1 and a flexural strength of 340 MPa were obtained. This study can provide a valuable reference for the industrial production of AlN ceramics. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) ceramic stands as a critical material in the realm of high-performance engineering ceramics. However, Crafting SiC ceramics with intricate structures and superior mechanical properties presents notable challenges in shaping, sintering, and processing. Binder jetting (BJ) additive manufacturing has the outstanding advantages of high forming efficiency and no thermal deformation, especially suitable for printing complex structure SiC components.; however, BJ printed green bodies often exhibit low density, resulting in high residual silicon content and diminished strength of the final components. In this work, we introduce a novel strategy to fabricate high-strength SiC components with complex geometries by improving the density of printed SiC green bodies. This method involves modifying the morphology of SiC powder through the molten salt method to increase the density of BJ 3D printed green bodies from 1.24 ± 0.13 g/cm³ to 2.01 ± 0.03 g/cm³, followed by a reactive melt infiltration process. The resulting RB-SiC ceramics display exceptional flexural strength, averaging 280.60 ± 33.05 MPa, and an elastic modulus of 294.67 ± 4.90 GPa. These values represent some of the highest for flexural strength and elastic modulus reported among 3D-printed SiC composites. With its robust mechanical performance and streamlined fabrication process, this strategy holds substantial promise for the production of structural SiC ceramics. [ABSTRACT FROM AUTHOR]

Engineering new chalcogenide solids improves the desired functionality of the materials and may open the way for new applications. Here we discuss the preparation of As x S 100−x amorphous thin films modified with WS 3 by the sol–gel method. We show that the formation of homogeneous, transparent, and stable n-propylamine-based solutions by mixing 0.02M As x S 100−x and 0.02M (NH 4) 2 WS 4 solutions is feasible for the As content in the chalcogenide glass precursor x ≤ 25 at.%. Above this limit, rapid and massive precipitation occurs in the solutions. We further demonstrate the preparation of amorphous thin films along the pseudo-binary AsS 3 - WS 3 tie-line and provide information about the role of WS 3 on optical properties and the structure of tungsten-based chalcogenide thin films. Due to a significant etching contrast between annealed AsS 3 − WS 3 thin films at 70 and 240 ∘ C , we propose tungsten-based chalcogenide thin films as a suitable platform for application in wet-lithography. [Display omitted] • Homogeneous, transparent, and stable solutions by mixing As x S 100−x and (NH 4) 2 WS 4 solutions for x ≤ 25 at.%. • The WS 3 content increases the thermal stability of prepared thin films. • Optically transparent amorphous AsS 3 − WS 3 thin films up to a molar ratio of 1:3. • As WS 3 increases, the absorption edge is red-shifted. • The chemical resistance decreases to amine-based solutions with increasing WS 3 content. [ABSTRACT FROM AUTHOR]

This study investigates the physical characteristics of un- and Mn-doped SnS nanoparticles (NPs) synthesized through a co-precipitation method. The undoped SnS is referred to as Mn 0, while Mn 1, Mn 2, and Mn 3 samples are obtained by incorporating 1, 3, and 6 mL of Mn-dopant solution, respectively. Elemental analysis is done by means of energy-dispersive X-ray spectroscopy (EDX), confirming successful Mn incorporation into the SnS lattice. X-ray diffraction (XRD) studies validate the formation of the SnS phase with a preferred orientation at the (040) plane for all samples. The crystallite size (D) of SnS NPs initially increases and then decreases after Mn-doping, confirmed by transmission electron microscopy (TEM) images. Field emission scanning electron microscopy (FESEM) images exhibit grain-shaped morphology with sizes ranging from 23 to 36 nm for all samples. The reduction in bandgap energy (E g) upon Mn-doping is attributed to variations in grain size and the formation of impurity levels within the SnS band gap. Mott-Schottky analysis showed p -type conductivity for all samples. The semiconductor parameters of SnS, such as the acceptor concentration (N A) and the density of states (N V), improved after Mn-doping. Current-voltage (I – V) curves revealed that the conductivity and mobility of SnS after Mn-doping initially declined for Mn 1 and Mn 2 samples and then improved for the Mn 3 sample. Electrochemical impedance spectroscopy (EIS) results align with the I – V findings. Consequently, it can be concluded that Mn-doping leads to enhancements in optoelectronic properties of SnS. [ABSTRACT FROM AUTHOR]

Plate-like grain toughening is an effective approach to enhance the toughness of ceramics. Herein, we propose a novel method to prepare platelet-toughened Al 2 O 3 /ZrO 2 ceramics by pressureless sintering without any additives. The Al 2 O 3 /ZrO 2 powder was prepared through combustion synthesis assisted by rapid water cooling. The synthesis process involved ultra-high temperatures and a rapid cooling rate, leading to the formation of Al-Zr-Y oxide solid solution with γ-Al 2 O 3 or t-ZrO 2 structure in the powders. The surface of the powder after being acid etched or annealed was investigated. The results indicated that the solid solution with γ-Al 2 O 3 structure exhibited a dendrite morphology, which could develop into plate-like Al 2 O 3 grains during annealing or pressureless sintering. Platelets can effectively improve toughness by inducing crack deflection. Furthermore, numerous ZrO 2 nanoparticles precipitated from the solid solution, which also contributed to the enhancement of mechanical properties. Consequently, the toughness and hardness of the ceramic could reach up to 10.76 MPa m0.5 and 15.5 GPa, respectively. Additionally, this method could be applied to fabricate platelet-toughened Al 2 O 3 /ZrO 2 ceramics with a wide range of Al 2 O 3 contents (60 wt%∼80 wt%), thereby catering to a wide range of industrial applications. [ABSTRACT FROM AUTHOR]

Laser‐based powder bed fusion (PBF‐LB) has gained prominence in the realm of additive manufacturing of metals. This technique utilizes a laser beam to consolidate powder layers, which inherently introduces high thermal gradients and rapid cooling rates. This results in characteristic process effects, including inhomogeneities, surface roughness, anisotropy, and residual stress, which play a pivotal role in altering the fatigue properties of the manufactured components. This paper presents fatigue tests involving samples of AlSi10Mg manufactured using PBF‐LB with varying surface roughness and residual stress. An approach to predict fatigue life based on stress amplitude, residual stress, and crack size is presented, using a smooth sample as a reference. An empirical model for fatigue life prediction is developed from experimentally measured values of fatigue life, peak surface roughness, and residual stress. [ABSTRACT FROM AUTHOR]

Core–shell structural B 4 C@TiB 2 composite powders were synthesized via the molten salt method using micron-sized B 4 C and TiH 2 powders as raw materials. Furthermore, a SiC composite ceramic with B 4 C@TiB 2 core–shell structural units as the toughening phase was prepared by spark plasma sintering using SiC powder and the obtained B 4 C@TiB 2 composite powder as starting powders. The effects of calcination temperature and raw material ratio on the phase compositions and microstructure of the B 4 C@TiB 2 composite powders were studied, and the synthesis mechanism of the B 4 C@TiB 2 composite powder was explored. The formation mechanism of B 4 C@TiB 2 core–shell toughening units inside the SiC matrix was investigated, and the toughening mechanism of the SiC–B 4 C@TiB 2 composite ceramic was discussed. Results show that the B 4 C@TiB 2 core–shell units in the SiC matrix can induce a complex crack propagation mode and consume abundant crack propagation energy. Therefore, a high fracture toughness of 6.47 ± 0.32 MPa m1/2 is realized for the SiC–B 4 C@TiB 2 composite ceramics. [ABSTRACT FROM AUTHOR]

By pre-milling in glucose aqueous solution, γ-Al 2 O 3 particles were uniformly mixed with carbon via hydrothermal treatment technique. Then, directly heating the γ-Al 2 O 3 /C precursor at 50 °C/min to 1775 °C for 15–30 min in N 2 , single phase AlON powder was fast obtained through one-step carbothermal reduction and nitridation (CRN). By approaching the evolution of phase assemblages and morphology during heating and dwelling, the one-step fast CRN mechanism for preparing fine AlON powder was revealed. The carbon around γ-Al 2 O 3 particles delayed the phase transformation of Al 2 O 3 from γ phase to α one. The undesired particle aggregation and growth before formation of AlON was also auxiliarily inhibited by swiftly achieving AlON formation temperature via high heating speed. Further elevating synthesis temperature enabled high reaction kinetics to boost the speed of AlON formation. By these ways, CRN reactions were quickly completed to fast obtain pure AlON powder with small primary particles due to limited particle aggregation and growth. The as-prepared fine AlON powder was easy to be ball-milled to prepare highly transparent AlON ceramics by pressureless sintering. [ABSTRACT FROM AUTHOR]

The potential of HfO 2 as a memory semiconductor material with ferroelectric properties in thin-film deposition has been recently analyzed. In this study, the preparation, composition, and physical properties of Al-doped hafnium oxides were analyzed. Hf x Al (1- x) O y (HAO) [ x = 0.33, 0.5, and 0.67] powders were prepared by controlling the ratio of Hf to Al and using ball milling. The HAO powder was calcined at 1000 °C in a furnace and then sintered in a temperature range of 1000–1600 °C by a solid-state reaction method to fabricate high-quality targets with high densities. The density and crystal size increased with the sintering temperature. The 1600-°C Hf 0.67 Al 0.33 O y target was optimal for thin-film deposition. In addition, the target properties were affected by an increase in the HfO 2 content x. The crystal structures and sizes, surface free energies, contact angles, and band gaps of the HAOs were evaluated to analyze their potential as high- k dielectric materials. HAO is a promising high- k dielectric and memory material, valuable for further studies on ferroelectric gate oxide materials. This study contributes to the increasing number of studies on the ferroelectricity of HfO 2 thin films and provides a fundamental understanding of this material and its potential for novel device applications. [ABSTRACT FROM AUTHOR]

A leading trend inmodern industry is hybridmanufacturing methods. The intention is to integrate additive and subtractive methods into a single machine. In such a process, it is difficult to evaluate the quality of the manufactured component between successive processes. A solution thatwouldmake it possible to determine the quality of a component produced by incremental technologies on the basis of forces recorded in amachining process is not yet available. In the present study, an attemptwasmade to reconstruct the surface of themachined workpiece solely on the basis of recorded forces during the groove micromilling process. A workpiece with a known surface geometry in the form of a sinuous wave was machined. The geometry of the workpiece corresponded to a structure typical of the selective laser sintering method for metallic powders. A process conducted with two different axial cutting depths was considered. The reconstructed surface profiles were evaluated by comparative analysis with the real machined surface. [ABSTRACT FROM AUTHOR]

Background: White spot lesions are a widespread undesirable effect, especially prevalent during fixed orthodontic treatments. The study compared the in vitro enamel remineralization potential of undemineralized dentin matrix (UDD) versus chicken eggshell powder (CESP) for artificially induced enamel lesions. Methods: 100 caries-free and sound maxillary premolars were randomly divided into four groups each contain 25 teeth: Group I (Baseline): No treatment was done to the enamel surface. Group II (Negative control): The enamel surface of the teeth underwent demineralization using demineralizing solution to create artificial carious lesions then kept in artificial saliva. Group III (CESP treated): After demineralizing the tooth surface, the teeth have been suspended in the CESP remineralizing solution. Group IV (UDD treated): After enamel demineralization, the teeth were suspended in UDD remineralizing solution. The remineralization potential was assessed by Vickers microhardness testing, scanning electron microscopic examination (SEM), and energy dispersive X-ray (EDX). Results: The current study demonstrated an increase in the mean microhardness of CESP and UDD-treated groups; however, It was nearer to the baseline level in the UDD group. SEM imaging revealed greater enamel remineralization in the UDD group compared to the remaining groups. The UDD group disclosed complete coverage for the prismatic enamel compared to the CESP group, which revealed a partially remineralized enamel surface. Interestingly, the Ca/P ratio increased significantly in the CESP group compared to the negative control group. In contrast, a higher significant increase in the mean Ca/P ratios was recorded in the UDD group compared to the test groups. Conclusion: biomimetic UDD and CESP powder should be utilized to treat enamel early carious lesions. However, UDD demonstrated the most significant remineralization potential. [ABSTRACT FROM AUTHOR]

MoAlB powders with a purity of 96 wt.% were successfully fabricated by a laser‐induced self‐propagating method using molybdenum boride (MoB) and aluminum powders as starting materials under the conditions of an n(MoB): n(Al) ratio of 1.0:1.4 and the laser linear energy density (El) of 0.9 J/mm, and the effect of raw material composition and El on the phase composition and microstructure of the resultant MoAlB powders were investigated. The minimum reflection loss (RLmin) value and effective absorption bandwidth (EAB) of the as‐prepared MoAlB absorber with a thickness of 5.0 mm were only determined as −12.5 dB (at 16.9 GHz) and 0.9 GHz (16.4–17.3 GHz) in the frequency of 1–18 GHz, respectively. Nevertheless, the RLmin and EAB of as‐prepared MoAlB powders oxidized after 3 h at 773 K increased to −18.59 dB (at 15.82 GHz) and 2.13 GHz (15.22–17.35 GHz), respectively, demonstrating that the as‐prepared MoAlB powders are potential candidates for high‐temperature microwave absorption applications. This study proposes a new efficient strategy for the preparation of boron‐based ternary compounds for high‐temperature electromagnetic wave absorption application. [ABSTRACT FROM AUTHOR]

Flash sintering has evolved into touch‐free sintering, where free‐standing workpieces can be sintered without attaching electrodes. Instead, the flash is transmitted from the surface of a reactor into the workpiece with superimposition of a magnetic field. Thus, sintering now depends on two independent parameters: the current used to sustain the flash in the reactor and the current flowing through the induction coil. We present a first report on the influence of these two parameters on the quality of the sintered workpiece. The specimens were made from whiteware, consisting of aggregates of ceramic particles interspersed with particles of a glass phase. The results are presented in a map with the reactor current and the induction current as the control variables. Three regimes are identified: insufficient sintering, good sintering, and the formation of defects. The reactor current emerges as an important variable: densification is poor if it is too low, and defects form if it is too high, with high density achieved in the intermediate regime. High induction currents are needed to achieve good sintering. Touch‐free flash sintering has also been shown to sinter and at the same time transform powders of elemental oxides into a single‐phase multicomponent ceramic. [ABSTRACT FROM AUTHOR]

Radiative cooling pigments offer new opportunities for sustainable carbon neutrality as zero‐energy and zero‐pollution functional materials. However, it is a challenge to prepare inorganic yellow pigments simultaneously with environmentally friendly, high color value, and weather resistance. In this study, a series of alkali metal‐doped γ‐Sm2S3 yellow pigments with near‐infrared reflectance were synthesized. The doping of alkali metal ions reduced synthesis temperature of Sm2S3 from 1300°C to 1000°C. The change in energy band structure induced by alkali metal doping allows the products to exhibit modifiable colors. Typical γ‐[Na]‐Sm2S3 pigment powders have a high near‐infrared reflectance and impressive colors (b* = 78.6, C* = 77.6). Furthermore, colored films made by prepared yellow powders with polyvinylidene fluoride in certain ratios had high near‐infrared reflectance and excellent environmental weathering, resulting in an effective cooling of 4–8°C in outdoor experiments. This work expands the range of options for energy‐efficient building and yellow colorant. [ABSTRACT FROM AUTHOR]

Wind turbine blades are primarily composed of fiberglass composite, posing a significant recycling challenge for the wind energy industry. This paper introduces a novel recycling approach by comprehensively analyzing the pozzolanic reactivity of recycled powder as a new supplementary cementitious material (SCM). A systematic characterization using laboratory techniques is first described, establishing both the chemical and morphological properties of the powder and suggesting that the material was likely to be capable of acting as a pozzolan. The effects of thermal and mechanical processing on the reactivity characteristics of the material were elucidated using a suite of analytical and standardized characterization approaches. It was found that through heat treatment to remove impinging resin and subsequent mechanical processing to synthesize a fine powder, the reactivity of the material could be improved to an extent at which the performance characteristics of a conventional class F fly ash were closely matched. For instance, mortar containing 10% of thermally-mechanically processed powder achieves 95% of the 28-day strength of cement mortar. This paper opens the door for both the use of these materials to bolster dwindling supplies of supplementary cementitious materials, and to provide a much-needed reprocessing route for waste fiberglass which are otherwise highly challenging to dispose of cost-effectively. [ABSTRACT FROM AUTHOR]

In this study, tungsten–copper (W–Cu) composite was fabricated using the sintering process to examine the corrosion, wear and hardness of the fabricated samples at three different temperatures of 1050, 1150 and 1300 °C. The potentiodynamic polarization behavior of the composite samples was evaluated in 3.5% NaCl solution containing different benzotriazole inhibitors. Finally, the microstructure of the W–Cu composite was examined by SEM, TEM, XRD and EDS analyses. The XRD results on the milled samples showed that the optimal conditions were obtained with a ball to powder ratio of 16:1 and a milling time of 15 h, so that the crystals with a size of 16.76 nm were obtained. Also, the highest hardness (185 HV) and relative density (97.34%) were obtained in the samples sintered at 1300 °C. With increasing the wear force, the work hardening increased in the mechanically mixed layer, which led to a rise in the wear rate and a decrease in the friction coefficient. The corrosion behavior of the composite indicated that by addition of 200 ppm inhibitor in the corrosion solution, the corrosion current density decreased from 3.73 to 0.59 μA/cm2 and the corrosion potential improved from − 630.46 to − 336.28 mVSCE. [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 Mg(OH) 2 –2Al(OH) 3 composite gel, synthesized via the sol-gel method, served as a modifier in the preparation of modified yttria partially stabilized zirconia (Y-PSZ) ceramics. The volume density, apparent porosity, compressive strength, thermal shock resistance, phase composition, and microstructure of the ceramics were systematically characterized. The findings reveal that, upon sintering, the Mg(OH) 2 –2Al(OH) 3 composite gel decomposes into MgO–Al 2 O 3 powder, which in turn in-situ generates a MgAl 2 O 4 spinel reinforcing phase, characterized by its uniform size and distribution. The presence of this MgAl 2 O 4 spinel applies compressive stress to the adjacent zirconia grains, effectively inhibiting their abnormal growth. By occupying the grain boundaries and establishing a mosaic structure, the compressive strength and thermal shock resistance of the Y-PSZ ceramics are significantly enhanced. Notably, an increase in the composite gel quantity correlates with a reduction in both volume density and apparent porosity of the Y-PSZ samples, whereas the compressive strength initially rises before diminishing, and the thermal shock resistance markedly improves. When the amount of Mg(OH) 2 –2Al(OH) 3 composite gel introduced reaches 9 %, the comprehensive performance of the modified Y-PSZ ceramics is optimized. At this point, its compressive strength is increased by 1.26 times compared to the unmodified Y-PSZ ceramics, reaching 732 MPa; moreover, after undergoing 60 thermal shocks, its residual strength retention rate still remains as high as 59.15 %. [ABSTRACT FROM AUTHOR]

The synergistic piezoelectric and osteoconductive properties of barium titanate (BT) and hydroxyapatite (HA) could stir the development of a new generation of synthetic bone graft substitutes, with capability for rapid and safe osseointegration. The research focused on two concurrent approaches for coupling the BT and HA materials: (i) conventional sintering of BT-HA powder mixtures; and (ii) functionalization of pre-sintered BT with HA coatings using magnetron sputtering (MS). Irrespective of the BT/HA ratios ranging from 95/5 to 80/20 wt%, nanocrystalline or highly-crystallized nature of the powders, sub-micron- or micron-sized particle dimensions, and sintering temperature, it was observed that the BT-HA reactivity cannot be prevented above 800 °C. At higher temperatures in the range of 1000–1300 °C, HA undergoes decomposition and extensively reacts with BT, leading to the formation of several secondary phases such as CaTiO 3, Ba 2 Ca(PO 4) 2 , BaCa 6 (PO 4) 4 O, BaCa(PO 3) 4 , and β -Ca 2 P 2 O 7. As a consequence, the cytocompatibility assessed in fibroblast and osteoblast cell cultures, as well as the piezoelectric response, were significantly altered. Applying HA coatings by MS to the sintered BT ceramics successfully preserved their piezoelectric properties, while also providing an unaltered cytocompatible and osteogenic-prone surface. The HA coatings were fully crystallized at post-deposition annealing temperatures of 550 and 700 °C, achieving crystalline qualities comparable to HA powders sintered at 1100 and 1200 °C, respectively. No reactivity events between BT and HA were observed. Partial reactivity was only noticeable upon annealing at 1000 °C. Therefore, it is suggested that the HA coating of BT is effective in seamlessly coupling the piezoelectric and osteogenic properties of the two constituents without compromise. • BT-HA powder mixtures inevitably react at high-temperature to form secondary phases. • The HA osteogenic component can be lost at sintering temperatures above 1000 °C. • The secondary phases lead to a decay of the piezoelectric and biological responses. • HA-magnetron sputtered BT – a feasible solution to overcome inter-phases reactivity. • HA-coated BT yields uncompromised piezoelectric and in-vitro biologic performances. [ABSTRACT FROM AUTHOR]

AlN powders with different O impurity contents were used to fabricate the high thermal conductivity (TC) AlN ceramics of different grain boundary (GB) phase distributions via pressureless sintering. Bending strength, fracture toughness, R -curve characteristic, and fracture mechanism of the ceramics were then investigated. The results showed that the GB phase distributions had great influences on mechanical characteristics of the ceramics. The ceramics with the continuous/semi-continuous GB phases possessed low strength and toughness. Comparatively, the ceramics with the isolated island-like GB phases, especially the fine GB phases at the triple AlN GB junctions, owned higher strength and toughness. The AlN ceramics principally followed the intergranular fracture mode, but the GB phase distribution had great effects on the fractions of transgranular fracture. The AlN ceramics with the continuous/semi-continuous GB phases had a lower fraction of the transgranular fracture, and thus lower crack propagation resistance and reliability than the others. [ABSTRACT FROM AUTHOR]

The inherent brittleness and uniform coloration of Si 3 N 4 materials have traditionally limited their applicability. In this study, colored Si 3 N 4 ceramics were synthesized utilizing α-Si 3 N 4 powder, a ternary mixture of sintering additives, and rare earth oxides (Eu 2 O 3 , Dy 2 O 3). The study focused on assessing the influence of varying Dy 2 O 3 content and holding time on the coloration, mechanical properties, and electromagnetic shielding properties of Si 3 N 4 ceramics. The incorporation of Eu 2 O 3 induced a color shift from gray to yellow-green, while the addition of Dy 2 O 3 facilitated the regulation of brightness in yellow-green Si 3 N 4 ceramics. The results reveal that both hardness and bending strength decreased with prolonged holding time, correlating with changes in sample density. The addition of rare earth oxides can effectively improve the fracture toughness of the Si 3 N 4 ceramics. Specifically, under conditions of 45 min holding time, 2%SED exhibited the highest fracture toughness at 8.45 MPa·m1/2. This enhancement can be primarily attributed to extended retention time, resulting in increased β- Si 3 N 4 phase content, improved fracture energy absorption, and a larger aspect ratio. The introduction of Eu 2 O 3 and Dy 2 O 3 did not significantly alter the electromagnetic shielding properties of Si 3 N 4 ceramics. This study offers novel pathways for the application of Si 3 N 4 ceramics in emerging fields. [ABSTRACT FROM AUTHOR]

The thermal decomposition and sintering kinetics of microfine magnesite were investigated to inaugurate a new One-step process for preparing high-density sintered magnesia. The optimal parameters for the discharging particle size of magnesite through ball milling were determined using an orthogonal experiment and Three-Way Measures ANOVA. The model for the thermal decomposition process of microfine magnesite was established through TGA-DSC and nonlinear regression analysis. Meanwhile, by describing the sintering process of microfine magnesite in detail through microstructure and CTE, the kinetic mechanisms of grain growth at different sintering stages were obtained. The results revealed that increasing the ratio of ball to powder can quickly obtain microfine magnesite which the bulk density reaches 3.45 g·cm−3 after One-step sintering. The thermal decomposition process required an activation energy of only 124.98 kJ·mol−1, which is much lower than existing technology and followed the Two-dimensional phase boundary reaction mechanism R 2. Additionally, the densification process was dominated alternatively by grain boundary diffusion and volume diffusion. This paper provided a detailed theoretical basis and leads a new direction in the One-step preparation of high-density sintered magnesia. [ABSTRACT FROM AUTHOR]

YFeO 3 (YFO) ceramics were synthesized by reverse co-precipitation at different pH values followed by microwave sintering (MS) and spark plasma sintering (SPS) techniques. Also, the effect of the grain size on the magnetic and dielectric properties of the sintered ceramics was examined using various characterization methods. Moreover, FESEM micrographs showed that the particle size of the calcined samples has declined by increasing the pH value. Furthermore, the magnetization curves exhibited weak ferromagnetic behavior in the pre-sintered powder samples. Besides, the M s value was enhanced from 1.26emu/g to 2.3emu/g by an increase in pH from 8.5 to 10.5 owing to reducing the particle size and subsequently raising the amount of uncompensated surface spins. Furthermore, the powder samples showed an increase in the H c and M r values from 15Oe to 28Oe and 0.127emu/g to 0.296emu/g, respectively, with a reduction in particle size from 0.632 μm to 0.272 μm. Additionally, the specimens processed through the sintering techniques demonstrated a remarkable reduction in magnetic characteristics. Therefore, a decrease in magnetic saturation values from 2.3emu/g to 0.43emu/g for the MS sample and to 0.17emu/g for the SPS specimen was attributed to a marked reduction in the amount of free surfaces and subsequently uncompensated surface spins. At last, the observed dielectric characteristics of all the sintered pellets had a common dielectric behavior. This signifies that by increasing the frequency the ε ′ and tanδ decline at lower frequencies and become frequency-independent at higher frequencies based upon the Maxwell-Wagner polarization theory. On the other hand, the ε ′ value for the SPS sample produced at pH = 10.5 underwent a decline of 2.5 times at the low frequency of 200 Hz compared to the MS one due to the significant decrement of the grain boundaries on account of the coarsening of grains. • The reverse co-precipitation method has been chosen to synthesize the YFeO 3 powders. • Through the particle size reduction, the higher pH levels resulted in the increased magnetization. • The spark plasma sintering method resulted in a higher grain growth compared to the microwave route. • The microwave sintering outperformed the spark plasma sintering in magnetic and electrical properties. [ABSTRACT FROM AUTHOR]

Ytterbium oxide (Yb2O3) ceramic powders at different Eu3+ mol concentrations, co-doped with a low molar ratio of Tb3+, were synthesized by the sol–gel process for study before and after the inclusion of the organic ligand thenoyltrifluoroacetone (TTA). The luminescent properties caused by the interactions between the Tb3+–Eu3+ ions before and after the antenna effect caused by the TTA were studied to investigate the relationships among their chemical, physical, structural and optical properties. Before the surface adhesion of TTA, the ceramic powders were composed of cubic crystalline structures that, in turn, consisted of large numbers of agglomerated particles exhibiting xerogel morphologies. The materials presented well-defined dispersive energy spectra, which indicated a suitable chemical composition. Subsequently, changes were induced through the superficial inclusion of TTA, these were characterized by promoting a greater luminescent intensity, especially for the emission bands corresponding to the 5D0→7F0-3 transition levels of the Eu3+ ion. [ABSTRACT FROM AUTHOR]

In this article, we prepared europium ions (Eu3+) doped lithium lutetium double tungstate material using a classical solid-state reaction. X-ray diffraction (XRD), optical absorption and photoluminescence techniques were used to characterize the samples. XRD analysis and structural refinement measurements revealed that LiLu(WO4)2 has a monoclinic structure with a P2/n space group with a formula unit (Z = 2). Additionally, we measured, analysed, and discussed the room-temperature photoluminescence emission and excitation spectra of Eu3+-doped LiLu(WO4)2. The emission spectra show the intra-configurational red emission characteristic of Eu3+ ions, namely 5D0 → 7Fj, J = 0–4. The quenching emission by temperature as well as the 5D0 emission decay curves were measured and discussed. It was found that the quenching of luminescence is obtained for 1.5 at% Eu3+ concentration. Judd–Ofelt intensity parameters (Ω2 = 5.26 × 10−20 cm2 and Ω4 = 1.04 × 10−20 cm2) and the 'Commission Internationale de l'Eclairage' (CIE) chromaticity coordinates were calculated from the emission spectrum of LiLu1−xEux(WO4)2 for x = 0.015. The results indicate that Eu3+-doped LiLu(WO4)2 could be a suitable material for solid-state lighting applications. [ABSTRACT FROM AUTHOR]

Monopotassium orthophosphate (MPOP) crystals in pure form and monopotassium orthophosphate crystals in doped form with non-essential amino acid L-serine (LSMPOP) are obtained by implementing slow evaporation solution growth techniques. The peaks of powder XRD graphical output, while comparing with the powder XRD pattern of pure MPOP, is found that 2θ values shifted slightly for L-serine-doped MPOP and this suggests that the formation of parent material is slightly disturbed by the dopant L-serine. The lattice constant and other crystal characteristics like volume, space group crystal system were analysed in detail by single crystal X-ray diffraction investigations and it is found that it belongs to I-42d space group and tetragonal structure. The infra-red Fourier transforms' spectral studies give information about the functional groups present in the pure and L-serine-doped parent material MPOP. The properties like optical energy gap, lower cut-off wavelength and transmittance were given by ultraviolet visible spectral inspections and the cut-off wavelength is found to be 382 nm for MPOP and 385 nm for LSMPOP, the band gap is found to be 2.85 eV for MPOP and 3.03 eV for LSMPOP. The microhardness of the title materials are calculated by Vickers microhardness studies. The electrical behaviours of MPOP and LSMPOP, such as dielectric constant, ac conductivity, impedance spectroscopy, activation energy are diagnosed and calculated by dielectric analysis. [ABSTRACT FROM AUTHOR]

Friction stir welding (FSW) is a process that can join many materials by causing minimal internal stress without the need for a direct electric current, contrary to traditional welding methods. The effects of SiC and Al2O3 reinforcing powders on the joining of AA6061-T6 and AA7075-T6 plates, which are difficult to join with conventional welding methods by FSW, are investigated in this study. The metallurgical properties of the combined samples are examined in terms of strength characteristics to investigate the effects of the reinforcement powder. In addition, elemental analysis is carried out for the mixing behavior of the powders. Finally, we used the TOPSIS method to select the most appropriate powder types to improve welding quality. Furthermore, a game theory application is presented to determine which powder type is suitable considering the joined aluminum plate's strength expectations. [ABSTRACT FROM AUTHOR]

The limited mechanical properties of Al–Si alloys hinder their application in demanding and extreme conditions. The cracking tendency of high-strength aluminum alloys and high-cost of rare-earth elements pose challenges for the large-scale application of aluminum alloys in additive manufacturing. The novel and practical high-speed scanning remelting proposed in this study enables Al–Si alloys to exhibit significant proportion of fine microstructures and nano-precipitates, surpassing the mechanical properties of aluminum alloys fabricated by normal methods with exceptional strength (496.1 ± 5.8 MPa) and plasticity (21.4 ± 0.9%). This in-situ microstructure control method opens new pathways for the application in demanding engineering contexts. [ABSTRACT FROM AUTHOR]

Liquid silicone rubber (LSR) is characterized by a wide range of advantageous properties and is therefore used in many branches and industries. However, the material is difficult to recycle due to the non‐reversible cross‐linking reaction. A promising approach to recycle the already cross‐linked (post‐industrial) waste is the mechanical recycling of LSR via grinding and addition of the powder as filler in virgin material. This research focused on the processing of such LSR‐powder‐compounds via injection molding and the influence of the powder content on mechanical properties. Compounds of virgin LSR and ambient ground powder were prepared and injection molded. Both the processability and the mechanical properties were analyzed. Compounds of up to 40 wt% powder content could be processed with standard injection molding machine equipment without any noticeable issues. The results show a similar compression set for the virgin as for the recycled compounds. Hardness decreases slightly but constantly. Tensile strength and elongation at break are at similar levels for all powder added compounds and drop only by 16.6% and 12.6% compared with the virgin LSR. The results are promising and should be the basis for further and more detailed investigations to industrialize the mechanical recycling of LSR. Highlights: Processing on standard injection molding machine with standard parameters.Up to 40 wt% recycled silicone powder content.Using recycled silicone particles has no effect on compression set.Tensile strength and elongation at break decrease only by 16.6% and 12.6%. [ABSTRACT FROM AUTHOR]

To investigate the granule reaction of two-micron aluminum powders with water at low temperatures, differential scanning calorimetry was used to analyze the initial exothermic temperature. Additionally, adiabatic accelerated calorimetry was employed to study the exothermic reaction under adiabatic conditions. The hydrogen production and particle size variation were investigated in order to gain insights into the Al-water reaction in a reactor with no induction time. Through focused beam reflectance measurement analysis, it was observed that during the reaction process of Al-water, particle sizes initially increased and then decreased. Specifically, the particle size of 3 μm aluminum powder experienced a 189% increase after the reaction while 25 μm aluminum powder decreased by 29%. Ultimately, both types of particles reached similar final sizes around 13.89 μm The process of Al-water reaction was explained and hydrogen production was analyzed, and the kinetic model was obtained. [ABSTRACT FROM AUTHOR]

The study aimed to develop gluten-free Riceberry rice pasta supplemented with cricket powder using a twin-screw extruder, contributing valuable knowledge to increasing the nutritional value of pasta through sustainable practices, nutritional enhancement, and novel ingredients. The D-optimal mixture design, an effective statistical tool for optimizing formulation, was used to determine the optimal proportions of Riceberry rice flour (RF, 75-90%), cricket powder (CP, 5-20%), and xanthan gum (XG, 1-5%). The results showed that all predictive models were statistically significant with satisfactory coefficients of determination (R² ≥ 0.75), and exhibited a non-significant lack of fit. The contour plot demonstrated that pasta with high RF, XG, and low CP contents had the lowest L* and highest a* values. The incorporation of XG increased firmness, while an increase in CP led to higher protein and fat contents in the pasta. A decrease in RF resulted in reduced total phenolic content (TPC), anthocyanin content (ATC), and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity (AOA). The sensory evaluation scores of the pasta, in terms of the texture attribute and overall acceptance, decreased as the proportion of XG increased. The optimization analysis showed that the highest desirability was achieved with RF, CP, and XG at 84.10, 14.45, and 1.45%, respectively. The optimally desirable product had the following properties: L* at 22.60, a* at 4.80, b* at 4.78, firmness at 3.41 N, protein content at 12.57%, fat content at 4.68%, TPC at 360.13 mg GAE/100 g dw, ATC at 476.24 mg C3G/100 g dw, AOA at 25.10 mg TE/100 g dw, texture rating at 7.40, and overall acceptance rating at 7.01. This study highlights the potential of cricket powder as a protein source in gluten-free Riceberry rice pasta. It offers insights into the effects of ingredients on pasta quality and facilitates the development of nutritious and appealing gluten-free pasta. [ABSTRACT FROM AUTHOR]

A novel algorithm, stretchedNMF, is introduced for non-negative matrix factorization (NMF), accounting for signal stretching along the independent variable's axis. It addresses signal variability caused by stretching, proving beneficial for analyzing data such as powder diffraction at varying temperatures. This approach provides a more meaningful decomposition, particularly when the component signals resemble those from chemical components in the sample. The stretchedNMF model introduces a stretching factor to accommodate signal expansion, solved using discretization and Block Coordinate Descent algorithms. Initial experimental results indicate that the stretchedNMF model outperforms conventional NMF for datasets exhibiting such expansion. An enhanced version, sparse-stretchedNMF, optimized for powder diffraction data from crystalline materials, leverages signal sparsity for accurate extraction, especially with small stretches. Experimental results showcase its effectiveness in analyzing diffraction data, including success in real-time chemical reaction experiments. [ABSTRACT FROM AUTHOR]

To solve the problem that Si was volatile and dense Si/SiC ceramics were difficult to achieve by spark plasma sintering (SPS) under a low sintering temperature and pressure, three kinds of SiC powders were used for particle grading and then ball‐milled with different time to further change and regulate their particle size and morphology, and finally nearly dense Si/SiC ceramics were prepared by SPS. The effect of milling time on particle size, morphology, tap density, phase, and microstructure of the SiC powders, as well as on bulk density, microhardness, thermal conductivity, phase, and microstructure of the Si/SiC ceramic, was researched. When the mixed SiC powders were ball‐milled for 12 min, the bulk density, microhardness, and thermal conductivity of Si/SiC ceramic were 2.96 g/cm3, 22.95 GPa, and 152.84 W/(m K), respectively. Ball milling changed the particle gradation and micro‐powder morphology and then affected the powder particle stacking state. Forming continuous pore channels was conducive for the volatile liquid Si to flowing and filling pores in a short time, resulting in denser Si/SiC ceramics at a lower sintering temperature and pressure. This study was useful for the preparation of ceramics containing volatile liquid phase by SPS. [ABSTRACT FROM AUTHOR]

The phytochemicals of high nutritional and functional properties in Lepidium sativum L. (garden cress) seeds have nominated their seed powder (regardless of the concentration used) for enrichment of mulberry leaves in order to enhance Bombyx mori L. larval feeding, and consequently to gain ground in sericulture industry. As expected, B. mori larval feeding on L. sativum-enriched mulberry leaves showed not only a remarkable increase in mean values of certain economic parameters of B. mori, such as cocoon weight, cocoon shell weight, pupal weight, and egg yield, compared with the control group, but also showed a phenomenal increase in egg counts (on average, ca. 958–1256 eggs laid per female moth) and a significant increase in egg size (measured as egg surface area and egg volume). Male or female moth larval diet has significantly influenced the reproductive performance or fitness of both sexes of B. mori in terms of large-sized moths (measured as forewing, hind femur, and hind tibia lengths) and highly fecund moths (i.e., increased fecundity and spermatophore counts per female moth, and large-sized eggs). On the basis of B. mori female moth reproductive index, the female moths from L. sativum-fed larvae proved to have a lower reproductive index compared to their corresponding value for females of the control group, indicating more efficient utilization of larval resources for B. mori reproduction. Quantification of the three main physiological resources viz., protein, lipid and carbohydrate in the internal reproductive tract of B. mori female moths at death has nominated the female moth abdomens, or simply their bodies, as being a reasonable natural source of protein, lipid, and carbohydrate, to be involved in certain manufactures (e.g., pet feed formulations) instead of discarding them as a source of environmental pollution. Evidently, the L. sativum seed powder is of considerable interest because it remarkably improves the performance of such an economically important insect, B. mori. This is the first study for evaluating the efficacy of L. sativum seed powder in sericulture field to enhance B. mori productivity parameters. [ABSTRACT FROM AUTHOR]

Ceramic saggars of mullite‐cordierite are currently used to produce cathode powders for lithium‐ion batteries. Strong interactions occur between the LiNi0.8Mn0.1Co0.1O2 (NMC) precursor in the temperature range of calcination (750–1000°C) leading to corrosion and formation of cracks in the saggar. The frequent failure of saggar causes a lot of waste, which could be reduced by choosing corrosion‐resistant materials. To understand the corrosion mechanism in the system MgO–Al2O3–SiO2, the materials MgO, Al2O3, MgAl2O4, and SiC (instead of SiO2) were embedded in premixed NMC precursor and calcined at T = 780°C for 50, 100, 150 and 200 h. The formed phases were determined by phase and microstructure analysis. Finally, the formation of LiAlO2 and Li5AlO4 is associated with a lower growth rate of the corrosion layer compared with Li4SiO4, while MgO is inert. The reactivity with NMC can be ordered as follows: SiO2 > Al2O3 > MgO. [ABSTRACT FROM AUTHOR]

The highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) poses a significant threat to the global swine industry. Vaccination is a preventive measure against viral infections. However, the use of vaccines in livestock healthcare programs faces the challenge of safety and delayed immune responses. Earlier studies have shown the potential of modified Bazhen powder as an immunomodulator with significant biological properties, but its effect on vaccines against HP-PRRSV is yet to be studied. This study elucidated how modified Bazhen powder could improve the safety and efficacy of the conventional PRRSV vaccine by evaluating T-cell responses, antibody levels, clinical symptoms, levels of viremia, organ health, and cytokine production. The results revealed that the oral application of modified Bazhen powder in combination with PRRS vaccination improved both cellular and humoral immunity, accelerated viremia clearance, improved lung injury scores, and reduced viral load in the tonsils. The modified Bazhen powder also effectively reduced inflammatory responses following a PRRSV challenge. These findings further highlight the pharmacological properties of modified Bazhen powder as a potential oral immunomodulatory agent that could enhance vaccine efficacy and ensure broad-spectrum protection against HP-PRRSV in pigs. [ABSTRACT FROM AUTHOR]

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Soft magnetic composite cores were produced by spark plasma sintering (SPS) from Ni3Fe@ZnFe2O4 and NiFeMo@ZnFe2O4 pseudo-core-shell powders. In the Fe-Ni alloys@ZnFe2O4 pseudo-core-shell composite powders, the core is a large nanocrystalline Permalloy or Supermalloy particle obtained by mechanical alloying, and the shell is a pseudo continuous layer of Zn ferrite particles. The pseudo-core-shell powders have been compacted by SPS at temperatures between 500–700 °C, with a holding time of 0 min. Several techniques were used for the characterisation of the powders and sintered compacts: X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, magnetic hysteresis measurements (DC and AC), and electrical resistivity. The electrical resistivity is stabilised at values of about 7 × 10−3 Ω·m for sintering temperatures between 600–700 °C and this value is three orders of magnitude higher than the electrical resistivity of sintered Fe compacts. The best relative initial permeability was obtained for the Supermalloy/ZnFe2O4 composite compacts sintered at 600 °C, which decreases linearly for the entire frequency range studied, from around 95 to 50. At a frequency of 2000 Hz, the power losses are smaller than 1.5 W/kg. At a frequency of 10 kHz, the power losses are larger, but they remain at a reduced level. In the case of Supermalloy/ZnFe2O4 composite compact SPS-ed at 700 °C, the specific power losses are even lower than 5 W/kg. The power losses' decomposition proved that intra-particle losses are the main type of losses. [ABSTRACT FROM AUTHOR]

To understand mechanical behavior of metastable metal-matrix composites, Cu@Ag core–shell powders of two compositions, 51:49 and 80:20 (Cu:Ag in wt%), were compacted by spark plasma sintering. The microstructures of these metastable metal-matrix composites are characterized by single spherical particulates of pure Cu in the matrix of pure Ag in the former case while by aggregates of Cu particulates in Ag matrix in the latter one. The plastic deformation showed enhancement of the ultimate tensile strength compared to both pure component metals by a factor of ca. 3. It is shown that a part of plastic deformation can be correlated by a logarithmic dependence but a possibility to apply a polynomial (quadratic) correlation is suggested. As expected, the shape of the particulate changes during plastic deformation and depends on the level and type of the plastic deformation. A model is proposed showing that this dependence is of a hyperbolic character. [ABSTRACT FROM AUTHOR]

Nanostructured amorphous composites are novel materials comprising nano-sized crystal phases embedded in an amorphous matrix, but often necessitating ultra-high-pressure molding for preparation. In this study, nanostructured amorphous ZrO 2 –Y 2 O 3 composite ceramics were rapidly prepared for the first time using flash viscous flow sintering without the application of pressure. The relative density of the ZY ceramics increased with increasing current density, and ZY composite ceramics with relative density of 86%–97 % were prepared by FS in a short time of 60 s under 700 V/cm with 0.16–0.56 A/cm2. Furthermore, the sintering activities in FS were compared between partially amorphous powder and crystalline powder. The ceramics prepared by flash sintering of partially amorphous powder show a much higher relative density than that from crystalline powder, suggesting that partially amorphous powder achieves easier densification than crystalline powder in flash sintering under given current density and power dissipation. This phenomenon was attributable to the differing sintering mechanisms between the two materials, i.e., solid-state sintering for crystalline powder and viscous flow sintering for partially amorphous powder. [ABSTRACT FROM AUTHOR]

Extending the transparency range of MgO–Y 2 O 3 composite ceramic to wavelength less than 3 μm is highly desirable, as it broadens their potential applications in infrared (IR) optics. This study illustrates the effectiveness of deagglomerating a mixture of magnesium oxide and yttrium sesquioxide powders, derived from self-propagating high-temperature synthesis (SHS), in achieving this goal. The impact of powder deagglomeration on the microstructure and porosity defects of hot-pressed MgO–Y 2 O 3 ceramic was analyzed using electron and IR microscopy. The results showed that the deagglomeration enhanced the homogeneity of the composite grain mixture, slowed down the grain growth, suppressed the formation of large grains, and significantly reduced the number of porosity microdefects in the material. The optical transmittance increased from 42 % to 77 % at a wavelength of 2 μm (for samples with a thickness of 1.2 mm) when deagglomerated powders were used, compared to non-deagglomerated ones. [ABSTRACT FROM AUTHOR]

Zirconia-toughened alumina (ZTA) ceramics have attracted much attention in the medical field as joint replacement materials due to their good mechanical properties and biocompatibility. However, the flexural strength of conventional ZTA is still slightly insufficient in traditional preparation techniques. In this study, by improving the slurry system, the effects of the solid content of the slurry, additives, and the pH of the slurry on the slurry system were investigated. ZTA powders with a uniform particle size distribution, high degree of sphericity and high flowability were prepared by spray granulation. The mechanical properties, microstructure and biocompatibility of the ZTA pressing were investigated after degreasing and sintering processes. The results showed that the hardness of the prepared ZTA ceramics was 1658.24 ± 28.04 H V, the fracture toughness was 4.016 ± 0.027 MPa m1/2, and the biaxial bending strength was 501.43 ± 21.44 MPa, and the three-point bending strength reached 635 MPa. The ZTA ceramics also possessed good biocompatibility and a low haemolysis rate, which aligns with the requirements of clinical biomedical implant materials. [ABSTRACT FROM AUTHOR]

High-quality Si 3 N 4 powder is a prerequisite for the preparation of high-performance Si 3 N 4 ceramics. In this paper, Si 3 N 4 powders with regular morphology were successfully prepared by pyrolysis of Si(NH) 2 using silicon as a nucleation inducing agent. The mechanism of the silicon in regulating the morphology and particle size of Si 3 N 4 powders was investigated. The results show that when Si(NH) 2 is pyrolyzed directly at 1500 °C under N 2 atmosphere, the products are mainly whiskers accompanied by some particles with irregular shape. In the presence of silicon, the powder particles exhibit a regular hexagonal prismatic morphology. With the increase of silicon content, the whisker content decreases obviously, and the whisker disappears completely when the silicon content exceeds 10 %. Furthermore, the particle size of Si 3 N 4 powder decreases with the increase of silicon content, and the particle size is the smallest when the silicon content is 15 wt%, which is about 802 nm. The nucleation and growth process of Si 3 N 4 powder particles can be divided into three stages. Firstly, silicon reacts with N 2 to form Si 3 N 4 nuclei. Then, amorphous Si 3 N 4 partially decomposes to form Si (g) and SiO (g) and grows on the formed Si 3 N 4 nuclei as the temperature increased. Finally, undecomposed amorphous Si 3 N 4 spontaneously nucleates and grows of the solid-phase diffusion mechanism. Ultimately, all the powders show equiaxial regular morphology. Preferential nitridation of silicon to form Si 3 N 4 nuclei provides nucleation sites for vapor-phase products, which is the key to inhibiting whisker formation and regulating the particle size of Si 3 N 4 powders. [ABSTRACT FROM AUTHOR]

Composite modification of fine SiC powder was implemented by 3-aminopropyl triethoxysilane (KH550) and sodium polystyrene sulfonate (PSS) to improve the dispersion stability of fine powder in water. KH550 was adopted as preliminary modifier and then PSS was used for second modification of KH550-SiC powder. Adsorption studies proved the preliminary modification of KH550 contributed to the adsorption of PSS on SiC particle surface and PSS saturated adsorption capacity was 4.473 mg/g. After KH550 and PSS composite modification, the zeta potential, stability and dispersibility of fine SiC powder were improved. The absolute value of zeta potential of KH550-PSS-SiC particle reached the maximum value of 46.4 mV at pH 12. KH550-PSS-SiC suspension had better stability at the pH range of 2–12. Subsequently, KH550-PSS-SiC powder was mixed with coarse SiC powder to prepare recrystallized SiC (RSiC) green body by slip casting. When the mass ratio of KH550-PSS-SiC powder to coarse SiC powder was 2:3, RSiC slurry with the solid loading of 70 vol% and the viscosity of 636.0 mPa s was obtained and then dense RSiC green body was produced. The density of the prepared RSiC green body was 2.6603 g/cm3 and the relative density was 82.70 %. [Display omitted] [ABSTRACT FROM AUTHOR]

This study utilized an innovative unalloyed CoCrFeNiTiMo hybrid powder as a joining filler to fabricate high‐strength SiC/HEA/SiC joints via in‐situ reaction. The investigation systematically examines the effects of joining parameters on microstructural evolution and mechanical properties. The filler exhibits high reactivity with SiC, addressing carbon enrichment and low‐strength issues. The resulting joining layer comprises HEA‐rich Si, Mo1.5Cr1.5Si, MoTiC2, and TiC phases. Increasing the temperature facilitates carbon diffusion, transforming TiC into MoTiC2 and forming a MoTiC2‐wrapped TiC structure. At 1400°C for 60 min, the joints attain peak flexural and shear strengths of 312 ± 16 and 137 ± 10 MPa, respectively. Additionally, the joints demonstrate excellent oxidation resistance, with a residual strength of 270 ± 7 MPa after 20 h at 900°C, and favorable high‐temperature mechanical strength, retaining 155 ± 14 MPa at 1000°C. A detailed analysis of the joint formation mechanism is conducted based on experimental results and first‐principles calculations. [ABSTRACT FROM AUTHOR]

The pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is far from over as new strains are emerging all over the world. Selenium as a micronutrient is important for immunity and also has anti-viral activity. Objective: The study evaluated the activity of a Selenium enriched garlic powder (SeGP or SelenoForce®) against SARS-CoV-2 viral replication in vitro and explored its possible mechanism of action. Methods: The anti-SARS-CoV-2 activity assay was carried out in Vero E6 cells in vitro. Human lung carcinoma A549 cells were used to study the antioxidant activity, expression of angiotensin converting enzyme (ACE), transmembrane protease, serine 2 (TMPRSS2) and the activity of proprotein convertase, and furin. Anti-inflammatory activity was evaluated in lipopolysaccharide-activated RAW 264.7 cells. Results: SeGP inhibited the replication of SARS-CoV-2 in Vero E6 cells with an IC50 of 19.59 μg/ml. It exhibited significant antioxidant activity in vitro with IC50 value determined as 43.45 μg/ml. The Selenium enriched product inhibited the expression of ACE and TMPRSS2 and also showed inhibition of furin protease activity. In the presence of SeGP, the secretion of nitric oxide, interleukin −6 and TNF-α were reduced in activated RAW 264.7 macrophages. Conclusion: The results of the study suggest that Selenium enriched garlic powder could inhibit SARS-CoV-2 multiplication in vitro, reduce oxidative stress and inflammatory mediators suggesting that it could be developed as an effective supplement or adjunct therapy to combat viral infections. [ABSTRACT FROM AUTHOR]