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Based upon global-minimum searches and first-principles electronic structural calculations, we present the perfectly planar B6O50/−/2− (1–3) systems. Notably, the C2v B6O50/− (1–2) clusters mark a groundbreaking advancement as the first boron oxide clusters to feature a five-membered ring. Both structures exhibit remarkable similarity, each characterized by a central B3O2 ring surrounded by three terminal BO groups. However, a notable difference lies in the bond lengths within the B3O2 core, which are uniform in the former but uneven in the latter. Detailed canonical molecular orbital and AdNDP analyses reveal the delocalized π bonds over the B3O2 ring, affirming the π aromaticity of B6O5−. The Cs B6O52− (3) cluster showcases a chain-like arrangement with three terminal BO groups and a typical OBO group linked to a B2 core, emphasizing the crucial role of electrons in shaping the structure. Detailed chemical bonding analyses reveal the presence of dual three-center four-electron (3c–4e) π hyperbonds in 3, shedding further light on its unique bonding characteristics. Moreover, this study comprehensively extends the B(BO)n0/− (n = 1–5) series and provides valuable perspectives on their structural evolution. [ABSTRACT FROM AUTHOR]

Transparent lithium aluminum silicon glass‐ceramics are prepared via heat treatment and the effect of boron oxide (B2O3) content on the structure and properties of Li2O‐Al2O3‐SiO2 glass‐ceramics is investigated. The X‐ray photoelectron spectroscopy results reveal that the parent glass containing B2O3 exhibits a higher concentration of bridging oxygen (BO). With an increase in B2O3 content, the relative amount of BO changes from 76.64% to 79.86% and then to 79.52%. Simultaneously, the second crystallization peak temperature TP2 of the samples increases from 715°C to 720°C and then to 724°C by differential scanning calorimeter analysis. The X‐ray diffractometer and scanning electron microscope results indicate that the addition of B2O3 facilitates grain growth, while an increase in B2O3 substitution for Al2O3 hinders the precipitation of LiAlSi4O10 but promotes quartz formation. The glass containing 2 wt% B2O3 with the heat treatment of 560°C/ 4 h+ 680°C/2 h shows a Vickers Hardness value of approximately 7.75 GPa, and a transmittance at 550 nm reaching ∼85%. [ABSTRACT FROM AUTHOR]

A novel approach was applied to synthesize B6O using CaB6 and B2O3 powders as reactants. CaB6 and B2O3 were reacted to generate B6O and CaB2O4 at 1573 K, and the by‐product CaB2O4 was removed by acid leaching. It was found that the samples prepared in this work were oxygen deficient (B6Ox, x ≈ .76–.77). The optimal molar ratio of CaB6 to B2O3 was determined to be 3:5, and excess B2O3 could not lead to a change in the value of oxygen occupancy. Scanning electron microscope images showed that regular holes similar to the morphologies of CaB6 particles were exhibited in the final samples, which could be explained by the diffusion of CaB6 during the reaction process. [ABSTRACT FROM AUTHOR]

This study aims to introduce a novel type of particulate reinforced Al matrix composite. High entropy (HfTiZrVNb)B 2 ceramic particulate reinforced Al matrix composites were produced via a combined process of different powder metallurgy methods. Firstly, boride compounds (HfB 2 , TiB 2 , ZrB 2 , VB 2 , NbB 2) were synthesized in the laboratory scale using the related metal oxide, boron oxide, and magnesium by mechanochemical synthesis (MCS) and leaching processes under optimum conditions. Secondly, the synthesized and purified boride powders were mixed in equimolar ratios using a planetary ball mill for 72 h, and they were sintered at 2000 °C under 30 MPa via spark plasma sintering (SPS). Thirdly, equimolar high entropy (HfTiZrVNb)B 2 bulks were crushed, converted into powder forms, and added into Al powders at different amounts as 1, 2, 5, 10, and 15 wt %. Lastly, these powder blends were mechanically alloyed in a vibratory ball mill for 6 h, cold pressed and pressureless sintered at 630 °C for 2 h. For characterization techniques, X-ray diffractometry (XRD), thermal analysis, scanning electron microscopy/energy dispersive spectrometry (SEM/EDS), density measurements using pycnometer and Archimedes' methods, microhardness and dry sliding wear tests were conducted on the sintered composites. The highest hardness (∼1.5 GPa) and the lowest wear rate (∼0.0012 mm3/Nm) were obtained in the Al-15 wt % (HfTiZrVNb)B 2 sample. [ABSTRACT FROM AUTHOR]

Metal‐free boron‐based catalysts such as boron oxide (B2O3) and boron nitride (h‐BN) are promising catalysts for methane oxidation to HCHO and CO. The B2O3 catalyst contains various probable boron sites (B1 to B6), which may be responsible for methane oxidation. In this work, we utilized density functional theory to compare two relevant geometrically identical boron sites (B2 and B4) for their reactivities. The two sites are explored in‐detail for the conversion of methane to formaldehyde (M2F), carbon monoxide and carbon dioxide. The B4 site activates the methane C−H bond easily as compared to the B2 site. In M2F conversion, the rate‐determining step for the B2 site is the co‐activation of dioxygen and methane, whereas over the B4 site, formaldehyde formation is the rate‐determining step. The computationally‐determined RDS for the B4 site coincides well with the reported experiments. It is further revealed that this site also prefers the formation of CO over CO2, which is in‐line with the experiments in literature. It is also shown through orbital analysis that methanol formation does not occur during methane oxidation. We employed descriptors such as condensed Fukui functions and global electrophilicity index to chemically distinct these twin sites. [ABSTRACT FROM AUTHOR]

Metal‐free boron‐based catalysts such as boron oxide (B2O3) and boron nitride (h‐BN) are promising catalysts for methane oxidation to HCHO and CO. The B2O3 catalyst contains various probable boron sites (B1 to B6), which may be responsible for methane oxidation. In this work, we utilized density functional theory to compare two relevant geometrically identical boron sites (B2 and B4) for their reactivities. The two sites are explored in‐detail for the conversion of methane to formaldehyde (M2F), carbon monoxide and carbon dioxide. The B4 site activates the methane C−H bond easily as compared to the B2 site. In M2F conversion, the rate‐determining step for the B2 site is the co‐activation of dioxygen and methane, whereas over the B4 site, formaldehyde formation is the rate‐determining step. The computationally‐determined RDS for the B4 site coincides well with the reported experiments. It is further revealed that this site also prefers the formation of CO over CO2, which is in‐line with the experiments in literature. It is also shown through orbital analysis that methanol formation does not occur during methane oxidation. We employed descriptors such as condensed Fukui functions and global electrophilicity index to chemically distinct these twin sites. [ABSTRACT FROM AUTHOR]

Within the scope of the study, glasses co-doped with Sm3+/Gd3+ based on the B2O3–GeO2–Bi2O3 system were synthesized, covering compositions of 40B2O3–40GeO2–(15 – 17)Bi2O3–(3 – 2)Sm2O3–(2 – 1)Gd2O3 and 42.5B2O3–42.5GeO2–(11.25 – 12.75)Bi2O3–(2.25 – 1.50)Sm2O3–(1.500 – 0.075)Gd2O3. An assessment of luminescent characteristics was carried out within the temperature range of 298 – 673 K. Spectral bands of photoluminescence associated with transitions between various Stark sublevels of Sm3+ ions were identified. Redistribution of the fluorescence intensity ratio corresponding to 4G5/2 → 6H9/2 ( λ PL max = 645 nm) and 4G5/2 → 6H7/2 ( λ PL max = 597 nm) transitions was observed. Based on the obtained data, calculations of the fluorescence intensity ratio FIR, as well as relative sensitivity SR, were carried out. The obtained results indicate the promising potential of these glasses as luminescent thermometric materials. [ABSTRACT FROM AUTHOR]

A novel binary transition metal oxide (NiFe2O4) nanosphere catalyst with a diameter of 500 nm has been synthesized by the hydrothermal reaction, which can efficiently catalyze the formation of hexagonal boron nitride nanotubes (BNNTs) with high‐yield and large aspect ratio. Based on the temperature dependence of the product phase composition and microstructure, combined with results generated using single‐component catalysts, the BNNTs formation process can be summarized as follows: NiFe2O4 reacts with NH3 to generate Fe0.64Ni0.36, which dissolves to form a liquid‐phase Ni‐Fe alloy at high temperatures, where the B component in the precursor and the N atom formed by the decomposition of NH3 diffuse on the surface of the Ni‐Fe alloy; when the concentration of B and N exceed the saturation threshold, hollow BNNTs containing catalyst at the tips are precipitated. The formation process is dominated by a vapor‐liquid‐solid mechanism with tip‐growth mode, where the synergistic catalytic effect of the Ni‐Fe binary system promotes a high yield of large aspect ratio BNNTs. [ABSTRACT FROM AUTHOR]

The addition of boron oxide is well‐known to dramatically extend the afterglow persistence (PersiL) from minutes to hours in Sr4Al14O25 (S4A7) co‐doped with 1 at% Eu and 1 at% Dy (S4A7EDxB), while the longest duration occurs when 30–40 mol% B2O3 is used. To elucidate the influence of B2O3 on the S4A7EDxB structure supporting PersiL, the thermodynamics and kinetics of phase transformation from amorphous preceramics of S4A7EDxB are investigated in the present work. Powders of S4A7EDxB containing x = 0, 10, 20, 30, and 40 mol% B2O3 were prepared by Pechini processing, and their phase evolution was analyzed at characteristic exothermic reaction temperatures. Differential thermal analysis and thermogravimetry at different heating rates, X‐ray diffraction, micro‐Raman, and scanning electron microscopy methods are used to reveal that S4A7 forms along different reaction pathways involving SrAl2O4, γ‐Al2O3, and SrAl4O7, with the pathway determined primarily by the amount of boron oxide present. Evidence is presented correlating the energy barrier of different phase transformations to the relative stability of Al3+ coordination polyhedral networks that form the scaffolding in each crystal phase. To lift the kinetic limitations for direct crystallization of S4A7, at least 30 mol% B2O3 is required for sufficient liquid borate to enable both the Sr2+ diffusion and the reorganization in topological connectivity in the Al3+ polyhedral scaffolding. [ABSTRACT FROM AUTHOR]

Copyright of SDU Journal of Engineering Sciences & Design / Mühendislik Bilimleri ve Tasarım Dergisi is the property of Journal of Engineering Sciences & Design 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.)

AbstractThe isothermal calcination kinetics of H3BO3 to B2O3 was firstly investigated as a function of time at 160, 200, 240 and 280 °C using heterogeneous and homogeneous reaction models and were characterized by XRD, FTIR-ATR, SEM and DTA/TG devices. Peaks in XRD patterns and bands in FTIR-ATR spectrum confirmed the structure of H3BO3 and B2O3. SEM showed that H3BO3 had a rather clean, flaky, smooth and plate-shaped surface while B2O3 had a rough surface. TG analysis confirmed that H3BO3 was degraded in two steps. Avrami model fitted a very good agreement with the experimental data. The activation energy was calculated as 14.2 kJ/mol. The smallest particle size for nano B2O3 was measured as 33 nm with Zetasizer NanoS. TEM images also confirmed that the particle size of B2O3 was measured to be approximately 50 nm. Additionally, the BET surface area of nano B2O3 was determined as 10.8 m2/g. [ABSTRACT FROM AUTHOR]

Solvothermal reaction of magnesium nitrate and boron oxide in N,N-dimethylformamide produced a number of particularly complex supramolecular magnesium borates. Five topologically different types of negatively charged {Mg@[B18ϕ34–35]}-clusters, ϕ = O, OH, were observed with the magnesium cation as a core and octadecaborate anions as shells. The clusters assemble via common borate polyhedra forming 1D chains, a 2D mesoporous layer, and 3D mesoporous frameworks with an effective channel width of up to 16 Å. Topological analysis of the clusters in combination with the modular crystallography approach indicates that numerous new functional materials can be obtained by varying their assembly mode. At least one compound containing such clusters exhibits a very strong luminescence. [ABSTRACT FROM AUTHOR]

Silicon carbide fiber‐reinforced SiC ceramic matrix composites (SiCf/SiC CMCs) based on a domestic KD‐SA SiC fiber were exposed to a wet oxygen atmosphere for 135 h at 800, 1100, and 1300°C. The evolution of the microstructure and mechanical properties of SiCf/SiC CMCs have been systematically investigated following oxidation. For weight change, CMC‐1300 showed the greatest gain (0.394%), followed by CMC‐1100 (0.356%) and CMC‐800 (0.149%). The volatilization of boron oxide (B2O3) combined with the slight oxidation of the SiC matrix at 800°C caused crack deflection and fiber pull‐out. The complete dissipation of the interphase could be found when the oxidation temperature increases to 1100°C, generated a fracture surface with brittle fracture characteristics. At 1300°C, crystalline SiO2 hindered oxygen diffusion, with evidence of fiber pull‐out. Based on thermodynamic calculations and microscopic observations, we propose a mechanism to explain the thermal degradation of SiCf/SiC CMCs. This work offers valuable guidance for the fabrication of SiCf/SiC CMCs that are suitable for high‐temperature applications. [ABSTRACT FROM AUTHOR]

With the aim of studying the occurrence of chromium reduction during argon-oxygen refining using boron oxide as a flux, thermodynamic modelling of the equilibrium interfacial distribution of chromium between slag of the oxide system CaO–SiO2–(3–6%)B2O3–12%Cr2O3–3%Al2O3–8%MgO in the range of basicity 1.0–2.5 and metal depending on temperature, boron oxide content, and basicity is performed. Modelling results are shown as diagrams of the dependence of the equilibrium interphase distribution of chromium on slag composition at 1600 and 1700 °C. It is found that an increase in slag basicity from 1.0 to 2.5 at 1600 and 1700 °C leads in the range of boron oxide content studied to a decrease in the interfacial distribution coefficient of chromium from 60.0 · 10−3 to 1.5 · 10−3 and as a result an increase in the degree of chromium reduction from 91 to 99.5%. An increase in metal temperature and boron oxide content have little effect on chromium reduction. The influence of basicity of the slags studied on the chromium reduction process may be qualitatively explained from the perspective of phases formed within slags and thermodynamics of chromium reduction reactions with aluminum and silicon. Experimental studies confirm results of thermodynamic modeling. [ABSTRACT FROM AUTHOR]

Bi-layer foamed glass-ceramic has the advantages of both dense and foamed structure which lead to low bulk density and high mechanical strength. We propose a new one-step method to produce bi-layer foamed glass-ceramic using the asynchronous oxidization of B 4 C and SiC. The parent glass is prepared by melting-quenching method, followed by foaming through powder sintering route with addition of B 4 C and SiC. The bi-layer structure and formation of bi-layers are investigated by scanning electron microscope (SEM), X-ray computed tomography, 11B NMR, and high temperature melting observation system (HTMOS). The results show that during the sintering process, the oxidization of B 4 C in top layer at low temperature forms boron oxide and helps the formation of glass melt in the top layer. The oxidization of SiC at high temperature leads to foaming in the top layer. The prepared bi-layer foamed glass-ceramic has low bulk density of 1.06 g·cm−3 and high flexural strength of 26.15 MPa. [ABSTRACT FROM AUTHOR]

Pyrolytic carbon (PyC) is widely used as the interphase in SiC f /SiC composites because of the crack deflection capability originating from its weakly bonded layered structure. However, the poor oxidation resistance limits its application in SiC f /SiC. Boron doping can improve oxidation resistance due to the crack-healing effects of boron oxide. To explore the optimal boron doping content in PyC interphase, structure characters and mechanical properties of C 128−x B x (x = 8, 20, 32, 44, 64) were simulated by ab-initio molecular dynamics. Modeling results suggest a transition of C 128−x B x from layered to amorphous accompanied by a change of its elasticity tensor from strongly anisotropic to nearly isotropic. The predicted optimal boron content is near 34 at%, at which the B-doped PyC maintains a layered structure with a high crack deflection potential according to the Cook & Gordon model while having a high crack-healing capability with a large volume expansion factor. [ABSTRACT FROM AUTHOR]

Copyright of Refractories / Naihuo Cailiao is the property of Naihuo Cailia (Refractories) Editorial Office 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.)

The classical simple picture of stepwise B‐to‐C migratory insertion of all three alkyl groups in the carbonylation reaction of trialkyl boranes with CO was shown not to be correct, except for the first alkyl group shift affording an acyl borane. The second and third direct alkyl shifts turned out to be kinetically hampered due to the non‐activated character of the B−C bond in electron‐poor B atoms. The latter can only be achieved by either the autocatalytic action of the final alkyl boron oxide or by formation of dimeric species with weakened B‐alkyl bonds at borate centres. Both thermodynamic and several NICS‐related parameters pointed to scarce, even "negative", aromatic character for boroxines, the final cyclotrimerization products of alkyl‐boron oxides. [ABSTRACT FROM AUTHOR]

Metallic glasses with high magnetomechanical power efficiency are widely used in laminated magneto-electric devices, from passive magnetometers and solid-state converters to very-low-frequency emitters. The remaining challenge is to simultaneously enhance the magnetomechanical power coupling and quality factors that are usually counterbalanced in metallic glasses. Here, we investigate the relaxations and surface configurations in annealed metallic glasses and their impacts on the magnetomechanical properties. We found an opportune annealing condition that maximizes the power efficiency when a surface-oxidation film of boron oxide is formed with excessive boron atoms that are separated from a surface-crystalline film. We confirm the findings by demonstrating a magneto-electric gyrator that has a power efficiency of 96% and magneto-electric antennas that have an increased emission intensity by 20% than that with traditionally annealed metallic glasses. [ABSTRACT FROM AUTHOR]

The emerging of single‐atom catalysts (SACs) offers a great opportunity for the development of advanced energy storage and conversion devices due to their excellent activity and durability, but the actual mass production of high‐loading SACs is still challenging. Herein, a facile and green boron acid (H3BO3)‐assisted pyrolysis strategy is put forward to synthesize SACs by only using chitosan, cobalt salt and H3BO3 as precursor, and the effect of H3BO3 is deeply investigated. The results show that molten boron oxide derived from H3BO3 as ideal high‐temperature carbonization media and blocking media play important role in the synthesis process. As a result, the acquired Co/N/B tri‐doped porous carbon framework (Co–N–B–C) not only presents hierarchical porous structure, large specific surface area and abundant carbon edges but also possesses high‐loading single Co atom (4.2 wt.%), thus giving rise to outstanding oxygen catalytic performance. When employed as a catalyst for air cathode in Zn‐air batteries, the resultant Co–N–B–C catalyst shows remarkable power density and long‐term stability. Clearly, our work gains deep insight into the role of H3BO3 and provides a new avenue to synthesis of high‐performance SACs. [ABSTRACT FROM AUTHOR]

Electrochemical production of hydrogen peroxide (H2O2) via the two-electron (2e−) pathway of oxygen reduction reaction (ORR) supplies an auspicious alternative to the current industrial anthraquinone process. Nonetheless, it still lacks efficient electrocatalysts to achieve high ORR activity together with 2e− selectivity simultaneously. Herein, a boron-doped defective nanocarbon (B-DC) electrocatalyst is synthesized by using fullerene frameworks as the precursor and boric oxide as the boron source. The obtained B-DC materials have a hierarchical porous structure, befitting boron dopants, and abundant topological pentagon defects, exhibiting a high ORR onset potential of 0.78 V and a dominated 2e− selectivity (over 95%). Remarkably, when B-DC electrocatalyst is employed in a real device, it achieves a high H2O2 yield rate (247 mg·L−1·h−1), quantitative Faraday efficiency (~ 100%), and ultrafast organic pollutant degradation rate. The theoretical calculation reveals that the synergistic effect of topological pentagon defects and the incorporation of boron dopants promote the activation of the O2 molecule and facilitates the desorption of oxygen intermediate. This finding will be very helpful for the comprehension of the synergistic effect of topological defects and heteroatom dopants for boosting the electrocatalytic performance of nanocarbon toward H2O2 production. [ABSTRACT FROM AUTHOR]

Nickel catalysts were synthesized for solid-state NaBH4 composites by reducing nickel chloride with sodium borohydride. The effect of heat treatment on their magnetic properties and the hydrogen generation rate was studied. It has been established that calcination of nickel catalysts to 350 °C has a negligible effect on the rate of gas generation but provides fast separation of more than 70% of the catalyst from the spent reaction medium using a magnet. According to XRD data (in situ) and the found Curie point value (358 °C), the enhancement of magnetic properties results from the accumulation of the ferromagnetic phase of the reduced Ni0 metal. A further increase in the heat treatment temperature (≥400 °C) decreases the activity of nickel catalysts, accompanied by a decrease in the specific surface area of the samples, by the complete conversion of cobalt boride Ni3B into the metallic form Ni0 and by the formation of the boron oxide shell around the nickel particles. To increase the activity of the nickel catalyst calcined at 350 °C, cobalt was deposited using incipient wetness impregnation, followed by reduction with sodium borohydride. The proposed technique allowed us to uniformly anchor cobalt on the surface of nickel particles, which ensured an increase in the gas generation rate. Thus, an effective ferromagnetic cobalt–nickel catalyst has been proposed for solid-state hydrogen-generating materials based on sodium borohydride. Note that the removal extent of this catalyst from the spent solution was about 85%. [ABSTRACT FROM AUTHOR]

Boron is one of the most valuable fuels for rocket propellants. However, the boron oxide (B2O3) on the B surface has a high boiling point (1860°C), which hinders the contact between the internal active B and the oxidation component during the ignition and combustion process. As a result, the ignition energy of B is higher and the combustion reaction rate is lower. In order to improve the ignition performance and reaction rate of B, a surface modification of B by means of surface purification by a solvent, surface grafting, and making a composite with aluminum (Al), which has a high combustion temperature, has been prepared. Composite particles of B purified by ethanol and thick flake Al (TF-Al), denoted by EB/TF-Al, have the fastest reaction rate higher by 96.6% than that of raw B and TF-Al composite particles (RB/TF-Al). Surface grafting of B with TF-Al composite particles (KHB-3/TF-Al) ensure the minimum ignition energy, which is 29.1% lower than that of raw B. As the ignition performance and reaction rate of B are improved by means of surface modification, the performance of B-based rocket propellants is expected to be improved. [ABSTRACT FROM AUTHOR]

We investigated the morphology and phase composition of tantalum diboride (TaB2) oxidation products by oxygen in the air across a temperature range of 20 to 1000°C. At isothermal conditions of 450, 500, 550, and 600°C, we determined the oxidation rate constants for TaB2 nanoparticles with an average particle diameter of ~70 nm (0.0006, 0.0027, 0.009, and 0.015 s–1, respectively). The apparent activation energy for the oxidation reaction of TaB2 nanoparticles, derived from the temperature dependence of the rate constants, was estimated to be 115 ± 6 kJ/mol. [ABSTRACT FROM AUTHOR]

The objective of this study is to explore how the replacement of barium oxide (BaO) by bismuth oxide (Bi2O3) affects the optical, structural and gamma rays shield ability of borate glasses. To accomplish this, a series of borate-based glasses was fabricated according the chemical formula 60B2O3 + (40-x) BaO + xBi2O3, where 0 < x < 10 wt.%. X-ray diffraction confirmed that an amorphous phase was present at all fabricated glasses. Thermal analysis indicated that Bi2O3 could serve as a glass modifier for all values of x greater than zero. Furthermore, the optical absorption profile showed that the samples had a greater absorption rate as x increased within the 1–4 eV photon energy range, with only minor fluctuations beyond 4 eV. Monte Carlo simulation demonstrated that increasing the concentration of Bi2O3 led to an increased radiation-absorbing capacity, where the linear attenuation coefficient of the fabricated glasses enhanced by 26% from 74.48 to 94.17 cm−1 at gamma ray energy of 0.015 MeV. Simultaneously, the half value thickness for the fabricated glasses reduced from 3.99 to 3.73 cm, raising the Bi2O3 concentration between 0 and 10 wt.%, respectively. These results indicate that adding Bi2O3 to boron oxides can significantly improve shielding the ability of the material to against gamma rays, alter the glass samples, and potentially be cost-effective. This study could lead to faster synthesis processes for glass modifiers, with important implications for designing and producing materials to shield against harmful gamma rays in industrial and medical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Micro-sized alloy type germanium (Ge) anodes possess appealing properties for next-generation lithium ions batteries, such as desirable capacity, easy accessibility and greater tap density. Nevertheless, volume expansion accompanied by severe pulverization and continuous growth of solid electrolyte interlayer (SEI) still represent fundamental obstacles to their practical applications. Herein, we propose a fresh strategy of constructing robust bond linkage between boron-based coating layer and lithiated polyacrylic acid (PAALi) binder to circumvent the pulverization problems of Ge anodes. Facile pyrolysis of boric acid can introduce an amorphous boron oxide interphase on Ge microparticles (noted as Ge@B 2 O 3). Then in situ crosslinking reaction between B 2 O 3 and PAALi via B O C bond linkage constructs a robust Ge anode (Ge@B-PAALi), which is proved by FTIR and Raman characterizations. Post morphological and compositional investigations reveal the minimized pulverization and a thinner SEI composition. The robust bond linkage strategy endows Ge anode with ultra-stable cycling properties of 1053.8 mAh/g after 500 cycles at 1 A/g vs. 500.7 mAh/g for Ge@PAALi and 372.7 mAh/g for Ge@B 2 O 3 , respectively. The proposed bond linkage strategy via artificial coating layer and functional binders unlocks huge potential of alloys and other anodes for next-generation battery applications. [ABSTRACT FROM AUTHOR]

A comprehensive theoretical and experimental study describing the effect of B 2 O 3 (0–30 wt%) on softening, liquidus, and crystallization temperatures, flow behaviour, and dynamic viscosity of the glass-based oxide system SiO 2 (64.64–43.21 wt%)-MgO(10 wt%)-CaO(15.86–7.29 wt%)-Al 2 O 3 (9.50 wt%)-B 2 O 3 with a constant basicity of 0.4 was carried out. The experimental data was obtained up to 1550 °C using a high-temperature rheometer and were supported by the study of the internal structure by means of scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray powder diffraction analysis, and Fourier transform infrared spectroscopy. The increasing addition of boron oxide caused a decrease in the start and end softening and liquidus temperatures. At 1550 °C, the systems exhibited Newtonian behaviour, with a dynamic viscosity increasing exponentially with a decreasing temperature and decreasing with increasing B 2 O 3 content. The amorphous character of the samples and the formation of structural units [BO 2 O−] and [BO 3 ] and [BO 4 ], confirmed by complementary analyses, led to a decrease in the degree of polymerization of the silicate structure. The theoretical insight into the dependence of dynamic viscosity on the temperature and composition was realized based on molecular dynamics. Furthermore, the prediction of viscosity as a function of temperature (1230–1550 °C) and the change in chemical composition (0–30 wt% B 2 O 3) was performed using artificial neural networks. [ABSTRACT FROM AUTHOR]

The widely used high-density polyethylene (HDPE) polymer has inadequate mechanical and thermal properties for structural applications. To overcome this challenge, nano zinc oxide (ZnO) and nano boron oxide (B2O3) doped lignin-containing cellulose nanocrystals (L-CNC) were blended in the polymer matrix. The working hypothesis is that lignin will prevent CNC aggregation, and metal oxides will reduce the flammability of polymers by modifying their degradation pathways. This research prepared and incorporated safe, effective, and eco-friendly hybrid systems of nano ZnO/L-CNC and nano B2O3/L-CNC into the HDPE matrix to improve their physio-mechanical and fire-retardant properties. The composites were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, thermo-gravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, horizontal burning test, and microcalorimetry test. The results demonstrated a substantial increase in mechanical properties and a reduction in flammability. The scanning electron microscope (SEM) images showed some agglomeration and irregular distribution of the inorganic oxides. [ABSTRACT FROM AUTHOR]

Solar-blind ultraviolet (SBUV) detection has a great prospect in a wide range of applications, in which the synthesis of semiconductor materials with a suitable bandgap can be an important research focus. In this work, BSnO films with good selectivity for SBUV were grown by magnetron sputtering with the bandgap adjusted from 4.1 to 5.3 eV. Based on the BSnO films, filter-less narrowband SBUV detectors were fabricated first, exhibiting a narrow detection range and an ultra-high responsivity (113 A/W) required by the detection of extremely weak SBUV signals. In addition, graphene/BSnO/SiC heterojunction photovoltaic detectors were also fabricated, with a high photo-to-dark current ratio and an ultra-fast response exhibited under 0 V bias, confirming their ability to handle the detection of transient signals. [ABSTRACT FROM AUTHOR]

Plasma doping (PLAD) technology is widely used in the semiconductor industry. One of the problems associated with PLAD is precise dosage control and monitoring during the doping process. Excessive boron doping into the n-type poly gate will affect the p-MOSFET threshold voltage. In this study, we develop a novel method for the real-time monitoring of the boron concentration as it penetrates into an oxide film. We attempted to determine whether the real-time monitoring of the boron concentration can be replaced by measuring the thickness of the damaged layer remaining after plasma doping and a cleaning process, since the thickness of the damaged layer can be measured relatively easily in real time by means of ellipsometry. It is found that as the plasma doping energy is increased, the boron concentration increases linearly, with a strong correlation (R2 = 0.98) between the plasma doping energy and the boron concentration. Moreover, there is a close relationship between the plasma doping energy and the thickness of the damaged layer. As the doping energy is increased, the thickness of the damaged layer also increases linearly. We also find a close correlation (R2 = 0.92) between the change in the thickness of the damaged layer and the p-MOSFET threshold voltage. In summary, there are very good correlations between the plasma doping energy and the concentration of boron, the doping energy and the thickness of the damaged layer, and the thickness of the damaged layer and the threshold voltage. It is proven that the concentration of boron penetrating into the oxide layer can be monitored by measuring the thickness of the damaged layer in real time. [ABSTRACT FROM AUTHOR]

This work focuses on wetting two types of substrates (a platinum substrate and a polished graphite substrate) by molten polycomponent oxide system CaO–MgO–SiO2–Al2O3–B2O3 to test the level of interaction at high temperatures. The tested systems were subjected to high-temperature wetting tests in the temperature range from liquidus temperature to 1550 °C using the sessile drop method. A total of four oxide systems were tested with graded boron oxide contents ranging from 0 to 30 wt%. The experiments were conducted in a CLASIC high-temperature resistance observation furnace and an inert atmosphere of high-purity argon. Droplet silhouettes were obtained with a CANON EOS 550D high-resolution camera during heat treatment, with reactive and non-reactive wetting occurring depending on the substrate type. The dependence of the average wetting angles on temperature and time was evaluated, and it was found that boron oxide decreased the average wetting angles of molten oxide droplets. The analyses were accompanied by the SEM/EDX analysis of the substrate and FTIR analysis of the droplets after high-temperature experiments. The phase composition of the oxide systems was evaluated by XRD analysis. [ABSTRACT FROM AUTHOR]

Inspired by the fact that nanostructured expandable graphite (denoted as EG), when functionalized with silicon (Si) and boron (B) elements, can significantly enhance thermal insulation performance and improve the strength of char residue layers, the study controllably synthesizes EG supported with boron acid (H3BO3) or polyhedral oligomeric silsesquioxane (POSS), using polydopamine (PDA) as a bridging agent. The resulting composites possess specific particle sizes of 80–90 nm and 100–120 nm for H3BO3-PDA-EG and POSS-PDA-EG, respectively. By formulating ablative-resistant coatings incorporating these composites, significant improvements are achieved in the mechanical properties of the resulting ceramic layers formed during ablation compared to control formulation. The compressive strength of the char residue layer is 0.13 MPa for EG alone, 8.85 MPa for H3BO3-PDA-EG, and 12.86 MPa for POSS-PDA-EG. Additionally, it is observed that the back surface of the coating with POSS-PDA-EG is approximately 180 ℃, while the back surface of the coating with H3BO3-PDA-EG is approximately 300 ℃ in a thermal test by a FD-04D/E Wind Tunnel, and compared to the coating with H3BO3-PDA-EG, the coating with POSS-PDA-EG yields more uniformly expanded and dense residue, which indicated that the coating with POSS-PDA-EG is characterized by better heat insulation and heat-resistant parameters. This is attributed to the improved silicon-boron coordination effect facilitated by the presence of POSS-PDA-EG and boron oxide, promoting ceramization. The resulting graphitized carbon layer, formed through fusion with porous expanded graphite at high temperatures, effectively resists high heat flow erosion over an extended duration. This work introduces an effective approach for enhancing ablation resistance by synergistically catalyzing boric acid or POSS-modified EG with a PDA bridge. The initial decomposition temperature was increased from 189 to 223 ℃, the maximum decomposition temperature was increased from 282 to 287℃, and the residual weight was increased from 51.6 to 63.6%. This can be concluded that the mixture of epoxy resin with either H3BO3-PDA-EG or POSS-PDA-EG demonstrates outstanding thermal resistance. The utilization of these novel composites and the insights gained from their performance contribute to advancements in the field of ablation-resistant coatings. [ABSTRACT FROM AUTHOR]

Bentonite is the traditionally used binder in iron ore pelletization. However, it consists of up to 85% silica and alumina which are undesired acidic gangue in iron-making. In this study, carboxymethyl cellulose, sodium lignosulfonate and cornstarch were used as acidic gangue-free organic alternatives to bentonite in synthesizing iron pellets. Iron ore, water and the corresponding binder were mixed and rolled in a pelletizing disk to form green pellets. The green pellets were dried and subsequently indurated in a furnace at 1200 °C to form indurated pellets. To evaluate the effectiveness of the organic binders, the pellets produced were tested on various pellet properties. Known industrial pellet property standards and the bentonite binder were used as references. Carboxymethyl cellulose, sodium lignosulfonate and corn starch produced green pellets with average drop numbers of 7.20 ± 0.84, 5.60 ± 0.89 and 6.00 ± 1.00 respectively, compared to bentonite's 5.00 ± 0.71. Dry pellets of average compressive strength 5.93 ± 0.09, 5.86 ± 0.03 and 11.52 ± 0.18 kg/pellet were produced by carboxymethyl cellulose, sodium lignosulfonate and corn starch respectively while bentonite's averaged 5.60 ± 0.08 kg/pellet. For indurated pellets, carboxymethyl cellulose (210.2 ± 1.88 kg/pellet) and sodium lignosulfonate (198.1 ± 2.49 kg/pellet) pellets were weaker than those of bentonite (250.4 ± 2.06 kg/pellet) but satisfied the industrial requirement of 181.4 kg/pellet. A boron oxide additive (0.1 wt. %) was used to boost the strength of carboxymethyl cellulose indurated pellets to 252.6 ± 1.32 kg/pellet, rendering them superior to those of bentonite. [ABSTRACT FROM AUTHOR]

A non-conventional mechanochemical processing technique was used to prepare fine-grain of mixed iron and vanadium oxides with a lead titanate system at boron oxide matrix. The structures of the ball milled samples were analyzed at different milling times and temperatures. After 30h of mechanical milling, the vanadium peaks completely disappeared, and partially supersaturated solid solution was formed. The average crystallite size of the 30h milled sample calculated from XRD patterns decreases rapidly from 3.72 μm to 69.4 nm while the crystallite size of the 50h was 26.3 nm. The DSC curve confirms the mechanochemical reactions. Metastable phases of lead vanadium oxide obtained after heat treatment with average crystallite size 65 nm in a non-crystalline matrix. The conductivity of the heat-treated samples increases with increasing heating temperature. The conductivity of all the prepared samples was found to be consistent with small polaron hopping, Mott's theory which confirmed by studying the power law behavior of its AC conductivity. The AC conductivity increases with increasing temperature and frequency. [ABSTRACT FROM AUTHOR]

The copper borate of CuB2O4 in tetragonal form was successfully synthesized as a single-phase by using a solid-state method without using any modifying agent. For the designed experimental procedure, the optimized reaction conditions were estimated as a reaction temperature of 950 °C, reaction time of 240 min, argon atmosphere and Cu:B ratio of 1:5. The possible reaction mechanism estimated for both boron sources of boric acid and boron oxide. In both sets, the lower ratios of Cu:B supported CuB2O4 formation. In the use of boric acid as a boron source, higher reaction yield percentages (98 %) and lower particle sizes were determined. The micron-scale rounded particles were observed in morphological analyses and the particles were shaped in homogeneity in the use of boron oxide as a boron source. The specific FT-IR peaks were observed at the band values of 1190, 1035, 988, 945, 890, 695, 631, 540 and 479 cm−1. The experimental results highlighted the probable use of solid-state in the copper borate synthesis. [ABSTRACT FROM AUTHOR]

The effect of partial SiO2 substitution with Al2O3 and B2O3 on the thermal properties and crystallization of glass sealants in the (50 − x)SiO2–30BaO–20MgO–xAl2O3(B2O3) (wt %) system is studied. It is established that the coefficient of thermal expansion of all obtained glasses lies within a range of 8.2–9.9 × 10−6 K−1. Alumina-doped glasses crystallize after quenching, while samples containing boron oxide are completely amorphous. Magnesium silicates are formed in all glasses after exposure at 1000 °C for 125 h. After 500 h of exposure, a noticeable diffusion of zirconium ions is observed from the YSZ electrolyte to the glass sealant volume, resulting in the formation of the BaZrSi3O9 compound. The crystallization and products of interaction between YSZ ceramics and boron-containing sealants have no significant effects on the adhesion and properties of glass sealants, which makes them promising for applications in electrochemical devices. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) metal oxides have broad prospective applications in the fields of catalysis, electronic devices, sensors, and detectors. However, non-van der Waals 2D metal oxides have rarely been studied because they are hard to peel off or synthesize. In this work, taking alumina (Al2O3) as a typical representative of 2D boron group oxides, the structural stability and electrical properties of 2D Al2O3 are investigated through first-principles calculations. The thinnest Al2O3 structure is a bilayer, and the band gap of Al2O3 is found to decrease with decreasing layer thickness because of the giant surface reconstruction. The band gap of bilayer X2O3 (X = Al, Ga, and In) decreases with increasing atomic radius. Our findings provide theoretical support for the preparation of non-van der Waals 2D boron group oxide semiconductors. [ABSTRACT FROM AUTHOR]

An innovative promising Gallic acid anchored poly vinyl alcohol via ethyl carbamate linker (PVA-EC-GA), was functionalized to extract boron from a tourmaline ore sample from Sikait area in South Eastern Desert of Egypt, which assaying 10.45% boron oxide. Specifications for PVA-EC-GA composite were accomplished by employing a variety of methods including XPS, FT-IR, EDX, BET, 1 H-NMR, TGA, 13C-NMR and GC-MS analyses, which assure an equitable prepare of PVA-EC-GA. Investigational measurements, namely: pH, agitation time, initial concentration of boron, composite dose, co-ions, temp. and agents of eluting, have been improved. At 25°C, pH 10, 20 min agitation and 0.0092 mol/L boron ions, PVA-EC-GA composite has an extreme uptake capacity of 43.75 mg per gram which is equivalent to 175 mg/L boron ions. From the isotherm modeling, Langmuir’s quite fitting the practical data. Conferring to kinetic modeling, pseudo-second order kinetic model well predicted the kinetics of boron ions adsorption by PVA-EC-GA giving a theoretical retention capacity of 43.86 mg/g. Thermodynamic prospects expose that the adsorption process was expected as an exothermic, spontaneous, and preferable adsorption at low temp. Boron ions can be eluted from the loaded composite, by 0.5 M H2SO4 with a 97% effectiveness. [ABSTRACT FROM AUTHOR]

The glass transition temperatures of common binary oxides, including those with low glass-forming ability, are estimated using pair distribution functions (PDFs) from ab initio molecular dynamics simulations. The computed glass transition temperatures for good glass-formers such as silica (SiO2), germania (GeO2), and boron oxide (B2O3) are in agreement with measured values. These calculations are then used to compute the glass transition temperatures of alumina (Al2O3), tantala (Ta2O5), and telluria (TeO2), which are known to exhibit low glass-forming ability. For Al2O3 and Ta2O5, we also compute the simulated caloric curve from molecular dynamics simulations using two-body empirical force fields. Finally, we discuss the possibility of extracting the glass transition temperature by measuring the thermal broadening of the PDFs from scattering measurements. [ABSTRACT FROM AUTHOR]

White-light luminescent Tm3+-doped borosilicate glass-ceramics were synthesized by the sol-gel method. The materials are predominantly amorphous with some embedded nanocrystals of H 3 BO 3 and B 2 O 3 with sizes ranging from 4 to 10 nm, which decrease as the Tm 2 O 3 content is increased. Moreover, the glass transition and crystallization temperatures enhance with the Tm 2 O 3 , showing higher thermal stability in the glass-ceramic with 0.50 mol%. Also, the addition of Tm 2 O 3 promotes an increase in the non-bridging oxygen concentration, the occurrence of the boric anomaly, and the incorporation of a higher amount of C species (C C and C O bonds) into the reticular structure of the glass ceramic. Therefore, the optical bandgap reduces (3.62–3.47 eV) while the photoluminescence intensity increases, being maximum at 0.75 mol% of Tm 2 O 3. Interestingly, the luminescent glass-ceramics show a white-emission color, CIE coordinates are (0.31–0.33, 0.33–0.34) instead of those corresponding to blue, which is what usually occurs in other Tm3+-doped materials. This characteristic photoluminescence emission is due to the 1D 2 →3F 4 electronic transitions of Tm3+ ions and the π– π* and n–π* transitions of C C and C O bonds originated by the carbon remnants inside the glass-ceramics. The released white emission has a correlated color temperature of 5600–6650 K, a color rendering index of ∼88, and a quantum yield of 12.3%. These materials are promising candidates for their use as phosphors in solid-state white-light-emitting devices. [Display omitted] • A simple sol-gel synthesis method, to obtain white-light luminescent thulium doped borosilicate glass-ceramics, was developed. • The addition of Tm 2 O 3 changes the glass-ceramics bulk density due to its high molecular weight and its network modifier effect. • The obtained glass-ceramics showed a predominant amorphous nature with some nanocrystalline boric acid and boron oxide phases. • The addition of Tm 2 O 3 promotes the increase of NBO concentration (Q1 and Q0 bonds) thus, the boric anomaly is taking place. • White emission is due to the π– π* and n–π* transitions of the C=Cand C=O bonds detected in the C 1s XPS spectra. [ABSTRACT FROM AUTHOR]

Boron‐based compounds such as frustrated Lewis pairs and borylenes that mimic transition‐metal(TM)‐like reactivity have attracted significant interest in recent years. This work examines the reactivity of boron oxide (B2O3) towards dioxygen for methane activation. Density functional theory in combination with orbital analysis were utilized to derive mechanistic pathways for methane‐to‐formaldehyde conversion over B2O3 in presence of closed‐shell singlet and triplet O2. Multiple pathways were screened on the triplet spin state. Best route via the triplet spin state depicts the interaction of B2O3 with dioxygen (O1=O2) and CH4 at a barrier of 49.8 kcal mol−1, to produce an intermediate having a B−O1−O2H unit and a free CH3 radical, which later react together at a barrier of 57.6 kcal mol−1, to finally yield HCHO. In the singlet spin state, a free CH3 radical does not form instead an intermediate with a B−O1−O2−CH3 unit is found after crossing a barrier of 41.1 kcal mol−1, which further undergoes via a relatively lower barrier of 23.4 kcal mol−1 to yield HCHO. Thus, the singlet pathway is energetically preferred over the triplet one. Orbitals further capture that at singlet and triplet states, methane activation follows a hydride and a hydrogen‐atom‐transfer mechanism, respectively. [ABSTRACT FROM AUTHOR]

In the realm of advanced materials engineering, the development of hybrid nanocomposites has garnered significant attention due to their superior mechanical properties and potential applications. The primary aim of this research is to develop a surface hybrid nanocomposite using Al1050 aluminium alloy (5 mm thickness) as the base material through friction stir processing. B _2 O _3 nano-powder, averaging 100 nm in size, and Cu micro-powder, averaging 5 μm in size, were incorporated into the aluminium surface in various volume ratios using the Friction Stir Processing (FSP). The processing parameters included a tool rotational speed of 1250 rpm, a feed rate of 50 mm min ^−1 , and a tilt angle of 3°. The number of passes was set at two levels: 1 and 3 passes. The influence of the volume ratio of constituents and the number of passes on the microstructure and mechanical properties of the resulting composite was thoroughly explored. The samples underwent tensile tests, microhardness tests, and metallographic examinations using both Optical Microscopy (OM) and Field Emission Scanning Electron Microscopy (FE-SEM). The composite with 25%-B _2 O _3 -75%-Cu composition exhibited the highest stress and hardness values, measuring 139 MPa and 58.14 HV, respectively. The enhanced strength of this sample is attributed to the presence of additives and the resultant grain size.

The boron oxide and zirconium silicide synergistic modified epoxy modified organosilicon resin composites were prepared and the ablation resistance properties of the composites were analyzed. With the synergistic effect of boron oxide and zirconium silicide, the properties, such as: the residue yield, hardness, tensile strength and ablation resistance (oxyacetylene ablation and static muffle furnace ablation) of the samples are markedly enhanced. The oxyacetylene linear ablation rate of the modified composite was observed to the minimum (0.04 mm s ^−1 ), when the contents of resin, boron oxide and zirconium silicide are 100 g, 50 g, and 150 g, respectively. The skeleton-like compact structure formed in the surface of composites after oxyacetylene ablation, which results in the best ablation resistance.

Cerium and boron are commonly used components to tune the acidic/basic property of catalysts in industry. In this work, cerium or boron‐doped copper‐based catalysts (xM−Cu/SiO2, M=Ce/B) were prepared with the ammonia‐evaporation method. Both X‐ray diffraction and Auger electron spectroscopy revealed that Cu+ content increased along with the Ce‐doping, but decreased by B‐doping. NH3‐Temperature Program Desorption results showed no change in the acidity of Ce‐doped catalysts, while significant amounts of medium‐strong acid sites appeared after B‐doping. Application in ethylene carbonate hydrogenation indicates the promoting role of Ce‐dopant in methanol production, while boron exhibits negative effects. The significant difference can be attributed to distinctive acidic/basic properties of Ce/B dopants, which affect the interaction between Cu and Si in the precursors, and thus adjust the ratio of Cu+/(Cu++Cu0). [ABSTRACT FROM AUTHOR]

Thermally conductive phase-change materials (PCMs) were produced using the crosslinked Poly (Styrene-block-Ethylene Glycol Di Methyl Methacrylate) (PS-PEG DM) copolymer by employing boron nitride (BN)/lead oxide (PbO) nanoparticles. Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) methods were used to research the phase transition temperatures, the phase-change enthalpies (melting enthalpy (ΔHm), and crystallization enthalpies (ΔHc)). The thermal conductivities (λ) of the PS-PEG/BN/PbO PCM nanocomposites were investigated. The λ value of PS-PEG/BN/PbO PCM nanocomposite containing BN 13 wt%, PbO 60.90 wt%, and PS-PEG 26.10 wt% was determined to be 18.874 W/(mK). The crystallization fraction (Fc) values of PS-PEG (1000), PS-PEG (1500), and PS-PEG (10,000) copolymers were 0.032, 0.034, and 0.063, respectively. XRD results of the PCM nanocomposites showed that the sharp diffraction peaks at 17.00 and 25.28 °C of the PS-PEG copolymer belonged to the PEG part. Since the PS-PEG/PbO and the PS-PEG/PbO/BN nanocomposites show remarkable thermal conductivity performance, they can be used as conductive polymer nanocomposites for effective heat dissipation in heat exchangers, power electronics, electric motors, generators, communication, and lighting equipment. At the same time, according to our results, PCM nanocomposites can be considered as heat storage materials in energy storage systems. [ABSTRACT FROM AUTHOR]

Agglomerates of ε -NbN hexagonal prismatic faceted grains with a size between 5 and 50 μm were formed by heating Nb 2 O 5 or NbFeO 4 powder and Na lump in a BN crucible at 900–1100 °C under an Ar atmosphere. Wavelength-dispersive X-ray analysis demonstrated that the ε -NbN faceted grains have a nearly stoichiometric composition. In addition to the ε -NbN grains, powders of niobium nitrides containing δ -NbN and Nb 2 N, and water-soluble Na 3 BO 3 were included in the sample prepared from Nb 2 O 5 at 1100 °C, while powders of Fe and Na 3 BO 3 , and a trace of δ -NbN were included in the sample from NbFeO 4. These reactions were attributed to metathesis reactions in which the oxygen in the oxides and the nitrogen in the solid nitrogen source, BN, were replaced by the formation of Na 3 BO 3. An extra amount of nitrogen supplied from the starting material enhances the formation of ε -NbN and suppressed the formation of δ -NbN and Nb 2 N. [ABSTRACT FROM AUTHOR]

The effect of basicity on the phase composition, structure, viscosity and crystallization temperature of CaO–SiO2–Al2O3–MgO–B2O3 fluorine-free slags was studied using vibrational viscometry and thermodynamic phase composition modeling in combination with Raman spectroscopy. The viscosity of the studied slags was established to depend mainly on the phase composition. Despite the complex reticular structure, consisting mainly of [SiO4] and [BO4] structural units with a large quantity of bridging oxygen, long slags (having a wide temperature range of viscosity variations) with low basicity possess high flowability in a liquid state as well as a low temperature of crystallization. This can be explained by the fact that the introduction of boron oxide is accompanied by the formation of a significant quantity of low-melting phases (CaO–B2O3, 2CaO–B2O3, and CaO–MgO–2SiO2) in the slag, which reduces the slag crystallization temperature, as well as increases its overheating and decreases viscosity. At an increase in basicity, long slags smoothly transform into short ones (with a narrow temperature range of viscosity variations); moreover, their structure is simplified along with an increase in the quantity of high-melting phases. In this case, despite the structural simplification, the slag crystallization temperature increases, which leads to the reduction in the degree of overheating and an increase in the viscosity. [ABSTRACT FROM AUTHOR]

Thermodynamic modeling of Zr–B–C–O quaternary system is conducted within the CALPHAD framework by employing data obtained from first‐principle calculations and literature. The lower order binary B–O is assessed in this work by estimating the thermodynamic properties of stable solid phases of B2O3 and B6O and by estimating the gas and liquid phases. First‐principle calculations, in conjunction with special quasirandom structure were used to predict enthalpies of mixing for the ternary solid‐solution phase of FCC‐Zr(C, O). The calculated results were used to optimize the model parameters pertaining to the cubic phase, which is described by a two‐sublattice model. The modeled Zr–C–O ternary phase diagrams calculated at 1923 and 2273 K under ambient pressure and 4 Pa, respectively, are in agreement with experimental phase diagrams. [ABSTRACT FROM AUTHOR]

The viscosities of the slags of the CaO–SiO2–Cr2O3–3% Al2O3–8% MgO–6% B2O3 system over a wide range of their chemical compositions are studied using the simplex lattice method of experimental design. For each viscosity, an adequate mathematical model described by a reduced third-degree polynomial is constructed. The results of mathematical modeling are presented graphically in the form of composition–viscosity diagrams. The slags in the composition region with a basicity of 1.5–2.0 are found to have a high fluidity in the temperature range 1600–1700°C: their viscosity does not exceed 0.3 Pa s. [ABSTRACT FROM AUTHOR]