Search

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]

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.)

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]

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]

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]

[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]

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 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]

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]

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.

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]

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]

B Cover Photograph b : Sandwich structures of hexagonal boron nitride (h-BN) with graphite cores hold the promise of exploiting the best of each material such as oxidation resistance (h-BN) with ease of processing (graphite). The cover image shows the complex interdiffusion of boron and carbon and the evolving reaction zone, which depends on the phase of the boron oxide reactant. Please read the Editor's Choice article "High-temperature carbothermal synthesis and characterization of graphite/h-BN biomaterials" (https://doi.org/10.1111/jace.18927) for more information. [Extracted from the article]

Boron-containing materials, and in particular boron nitride, have recently been identified as highly selective catalysts for the oxidative dehydrogenation of alkanes such as propane. To date, no mechanism exists that can explain both the unprecedented selectivity, the observed surface oxyfunctionalization, and the peculiar kinetic features of this reaction. We combine catalytic activity measurements with quantum chemical calculations to put forward a bold new hypothesis. We argue that the remarkable product distribution can be rationalized by a combination of surface-mediated formation of radicals over metastable sites, and their sequential propagation in the gas phase. Based on known radical propagation steps, we quantitatively describe the oxygen pressure-dependent relative formation of the main product propylene and by-product ethylene. Free radical intermediates most likely differentiate this catalytic system from less selective vanadium-based catalysts.

Oxidative dehydrogenation of propane is a promising technology for the preparation of propene. Boron-based nonmetal catalysts exhibit remarkable selectivity toward propene and limit the generation of COx byproducts due to unique radical-mediated C–H activation. However, due to the high barrier of O-H bond cleavage in the presence of O2, the radical initialization of the B-based materials requires a high temperature to proceed, which decreases the thermodynamic advantages of the oxidative dehydrogenation reaction. Here, we report that the boron oxide overlayer formed in situ over metallic Ni nanoparticles exhibits extraordinarily low-temperature activity and selectivity for the ODHP reaction. With the assistance of subsurface Ni, the surface specific activity of the BOx overlayer reaches 93 times higher than that of bare boron nitride. A mechanistic study reveals that the strong affinity of the subsurface Ni to the oxygen atoms reduces the barrier of radical initiation and thereby balances the rates of the BO-H cleavage and the regeneration of boron hydroxyl groups, accounting for the excellent low-temperature performance of Ni@BOx/BN catalysts. The working temperature of boron-based catalysts reduces their thermodynamic advantages in the oxidative dehydrogenation of propane (ODHP). Here the authors demonstrate encapsulated Ni nanoparticles as effective subsurface promoters to enhance the low temperature activity and selectivity of the boron oxide overlayer in ODHP. [ABSTRACT FROM AUTHOR]

The influence of boron oxide additives in amounts 0 to 11 mol.% on the melting properties of glasses in the system SrO–Al2O3–TiO2–ZrO2–B2O3–SiO2 for use as fillers in dental filling composites in order to lower the melting temperature to technologically acceptable values (≤ 1500°C) and to increase the transparency of the produced finely crushed glass. It was found that as the B2O3 content increases, the melting temperature can be lowered from 1600°C (in glass without added B2O3) to 1480°C at B2O3 content 11.8 mol.%, and the glass transition temperature drops from 820 to 743°C. Transparent glasses with light transmission 80%, which are promising for making filling composites, already obtain at 6 mol.% B2O3 with melting temperature 1500°C. [ABSTRACT FROM AUTHOR]

The Tb2O3–Li6Tb(BO3)3 system, promising for the growth of cubic terbium oxide crystals, has been characterized by physicochemical techniques. We have studied terbium oxide solubility in Li6Tb(BO3)3 and the vaporization of a saturated solution in the temperature range 1055–1285°C. The solubility results have been compared to data in the literature and represented graphically. The high-temperature solution has been shown to vaporize incongruently. The major components of the vapor phase are lithium and boron oxides, in the ratio near Li2O : B2O3 = 4 : 1. As the vaporization temperature is raised, the percentage of terbium oxide in the composition of the vapor phase increases. At 1250°C, the ratio of the constituent oxides in the vapor phase is Li2O : B2O3 : Tb2O3 = 62 : 15 : 1. [ABSTRACT FROM AUTHOR]

Over the last 20 years, many polymer-based additives have been used in asphalt modification. The extensive utilization of these additives and their inability to biodegrade create environmental concern for humans. Therefore, discovering affordable and naturally occurring asphalt polymers has become prominent. In this study, a new asphalt modifier was produced under laboratory conditions by synthesizing boron oxide with rosin (colophony resin), which is naturally produced from pine trees. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC)/thermogravimetric (TG), and X-ray powder diffraction (XRD) analyses were used to determine the microstructural characteristics of the produced modifier. The SEM analysis showed that the new modifier was distributed homogeneously the asphalt matrix, the FTIR and XRD analyses showed that a chemical synthesis had taken place, while the DSC and TG analyses determined the thermal structure characterization and temperature range of the modifier. The rheological properties of the modified asphalts were investigated by conducting penetration, softening point, ductility, flash point test, rotational viscosity (RV), and dynamic shear rheometer (DSR) tests. The results showed that the new modifier could be produced in a laboratory environment, the temperature sensitivity of the original asphalt was reduced by 48% with a 3% additive rate, and the modified asphalt provides a wide range of usage in hot climates. Conclusively, the boron-added resin compound (BARC) additive did not adversely affect the workability and pumpability properties and the BARC-modified asphalt binders significantly increased the rutting resistance. [ABSTRACT FROM AUTHOR]

Thermal contact resistance between the microprocessor chip and the heat sink has long been a focus of thermal management research in electronics. Thermally conductive gel, as a thermal interface material for efficient heat transfer between high-power components and heat sinks, can effectively reduce heat accumulation in electronic components. To reduce the interface thermal resistance of thermally conductive gel, hexagonal boron nitride and graphene oxide were hybridized with a low-melting-point alloy in the presence of a surface modifier, humic acid, to obtain a hybrid filler. The results showed that at the nanoscale, the low-melting-point alloy was homogeneously composited and encapsulated in hexagonal boron nitride and graphene oxide, which reduced its melting range. When the temperature reached the melting point of the low-melting-point alloy, the hybrid powder exhibited surface wettability. The thermal conductivity of the thermally conductive gel prepared with the hybrid filler increased to 2.18 W/(m·K), while the corresponding thermal contact resistance could be as low as 0.024 °C/W. Furthermore, the thermal interface material maintained its excellent electric insulation performance, which is necessary for electronic device applications. [ABSTRACT FROM AUTHOR]

Focusing on the serious volatilization of MoO3 in super austenitic stainless steel with a high Mo content, the influence of B on the formation of oxide film and the distribution of Cr and Mo was investigated at 900 °C and 1000 °C. Without the addition of B, Mo tends to diffuse to the surface, forming porous Cr/Mo-rich oxides, causing the volatilization of Mo. The addition of B can inhibit the diffusion of Mo to the surface, facilitate the diffusion of Cr to the surface and combines with O, providing conditions for the nucleation of Cr2O3. A large amount of Cr2O3 accumulated on the surface to form a dense passive film, which inhibited the diffusion of Mo to the surface, reduced the loss of Mo, and formed Mo/Cr-rich precipitates at grain boundaries that are close to the surface. However, it was difficult to form Mo-rich precipitates at the grain boundaries of a sample without B, which aggravated the volatilization of Mo from grain boundary to surface. Therefore, the addition of B can improve the oxidation resistance of 254SMO and inhibit the volatilization of Mo. [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.

The interesting characteristics of graphyne structure inspired this research to study the effect of oxygen incorporation and boron nitride doping on γ-graphyne. The structural stability, vibrational, and electronic properties of γ-graphyne, γ-graphyne oxide, and boron nitride doped γ-graphyne have been studied via density functional theory. The negative formation energy verified the structural stability of all the structures. Both γ-graphyne oxide and boron nitride doped γ-graphyne showed a significantly deformed geometry compared to pure γ-graphyne. The energy gap of pure γ-graphyne was obtained to be 2.604 eV, which tuned to 3.059 eV and 3.51 eV through oxygen addition and boron nitride doping, respectively. Boron nitride doped γ-graphyne revealed better structural stability, whereas high reactivity was observed for pure γ-graphyne. [ABSTRACT FROM AUTHOR]

Composite materials based on molybdenum disilicide, boron and aluminum oxide were obtained by heat treatment of mixtures of initial components in the form of finely dispersed powders in air. In the course of chemical reactions, a glass-forming melt is formed, which encapsulates the initial powder particles, which provides increased heat resistance of the composite material. The effect of temperature–time parameters on the phase composition and microstructure of glass–ceramic composites has been determined. [ABSTRACT FROM AUTHOR]

We have attempted to develop the gamma radiation shielding abilities of newly prepared epoxy composites by introducing ZrO2. The radiation shielding parameters are experimentally reported below. The experimental setup included an HPGe detector and different radioactive point sources which emitted photons with energies of 0.06, 0.662, 1.173, and 1.333 MeV. The gamma radiation shielding abilities of the epoxy composites were examined in the context of the linear attenuation coefficient (LAC), half-value layer (HVL), radiation absorption ratio, and other factors. The experimental and Phy-X results for the LAC were compared, and acceptable consistency was reported. The lowest LAC values were reported for EBZr-0 (free of ZrO2), and we found that the photon attenuation competence of the present epoxy improved as a result of increasing the ZrO2 content. We compared the LAC values for the present epoxy composites with other samples, and we found that the prepared composites with 20% to 40% ZrO2 had higher LAC values than epoxy with 30% Yahyali Stone. The HVL lengths of the epoxy composites reduced with the addition of ZrO2 for the four selected energies, which confirmed that introducing ZrO2 improves the radiation absorption abilities of epoxy composites. At 0.06 MeV, the HVL for the ZrO2-free epoxy was 2.60 cm, which fell to 0.23 cm after adding 40% ZrO2. The mean free path (MFP) for the prepared composites was less than 1 cm at 0.06 MeV (standard for EBZr-0), while it was 1.32 cm for EBZr-10. For the other energies, it was higher than 6 cm, and became higher than 10 cm at 1.333 MeV for all composites. The obtained results suggest that non-toxic, natural, and cheap epoxy composites with high ZrO2 content have the potential to improve the gamma ray shielding competence of epoxy composites for low energy radiation applications. [ABSTRACT FROM AUTHOR]

The effect of V2O5 and B2O3 additions on sintering behaviour and physical properties of ZnO ceramics was investigated. XRD studies revealed ZnO as main phase with a hexagonal wurtzite-type structure. The V2O5 addition is the reason for an increase in grain size and some grains of oblong shape morphology in the ZnO ceramics. The dual addition of V2O5-B2O3 improved the liquid-assisted sintering of ZnO ceramics and resulted in further increase in grain size with more uniform grain growth. The reduction of sintering temperature to 900°C for ZnO ceramics was observed with the dual addition of V2O5 and B2O3. The room temperature PL spectra of the Z (ZnO), ZV (ZnO with 0.5mol% V2O5) and ZVB (ZnO with 0.5mol% V2O5 and 0.5mol% B2O3) ceramics revealed broad visible emission band because of impurities and defects in ZnO ceramics caused by oxygen vacancies due to vanadium and boron additions, as well as zinc interstitials. This emission band between 450-750 nm includes the entire visible region from blue to red.

Borate and boron oxide containing bioactive glasses have drawn attention because of their unique properties and potential biomedical applications. In this paper, we review recent advances in understanding of boron oxide addition on the structures and properties of bioactive glasses from both experimental and simulation studies. After reviewing the synthesis, characterization and applications of these novel bioactive glasses, recent developments of simulation methodologies including the interatomic potentials to model boron oxide containing bioactive glasses are reviewed. Effect of boron oxide to silica substitution on a range of properties such as density, glass transition temperature, coefficient of thermal expansion, diffusion and mechanical properties, as well as crystallization behavior, both from our own studies and those from literature, are summarized. Furthermore, influence of boron oxide on in vitro bioactivity in several bioactive glass series are reviewed and discussed, emphasizing the importance of in vitro testing conditions on the bioactivity evaluation. Lastly, an outlook of future directions of the field has been provided.

A novel pathway for the magnesiothermic reduction of boron oxide and magnesium dodecaboride (MgB12) in the presence of carbon by a self-propagating high-temperature synthesis method was proposed that was aimed at the direct preparation of boron carbide nanopowder. The combined utilization of two boron sources, boron oxide and MgB12, allowed tailoring the overall caloric effect of the process, increasing the yield of the target product and lessening the laborious leaching process. In addition, it is an alternative way to utilize magnesium borides, which are inevitable side products at boron production. Multivariate thermodynamic calculations performed in the B2O3-MgB12-Mg-C system allowed estimating equilibrium compositions of the products and deducing the optimum composition of the initial mixture for obtaining B4C. For the latter, the adiabatic temperature (Tad) is 2100 °C, which is theoretically enough for the implementation of the self-propagating reaction. The combustion reaction was shown to be extremely sensitive to the initial mixture composition, external pressure, as well as sample diameter (heat losses). It proceeds in self-oscillatory mode and leads to the product of a layered macrostructure. The combustion product was then consolidated by the spark plasma sintering technique at different conditions. Vickers microhardness was measured, and the wear erosion behavior was examined. The variation in lattice parameters of boron carbide reflected the influence of synthesis, sintering and erosion conditions on the ordering/disordering of the boron carbide structure. [ABSTRACT FROM AUTHOR]

Highly purified and crystallized hexagonal boron nitride (h‐BN) powder is suitable as thermally conductive filler in resins. To obtain h‐BN powder with large particle size, as well as high purity and crystallinity, high‐temperature heat treatment over 1800°C in a N2 gas atmosphere is effective. The carbothermal reduction nitridation (CRN) involves the carbothermic reduction of boric oxide in a N2 gas atmosphere. In CRN using a CaO promoter, h‐BN particles with high crystallinity can be obtained by a simple heat treatment process. CaO prevents the evaporation of boron oxide and aids in h‐BN particle growth at high temperatures. However, CaB6 is formed as byproduct or impurity when CRN using the CaO promoter is performed at temperatures higher than 1800°C. In this study, the relationship between the products and the reaction temperature was clarified via thermodynamic considerations and experimentation. The results clarified the ideal reaction process of CRN using a CaO promoter to obtain highly purified and crystallized h‐BN powder. [ABSTRACT FROM AUTHOR]

We investigate coatings sprayed by the electric-arc method from solid and powder wires, and study their structure, mechanical properties, and tribological characteristics. The drops of the powder and solid wires are present in the coatings obtained from heterogeneous wires. The structure of the coating consists of two different frames, namely, of the soft matrix of solid wire (150–450 HV100) and of the hard matrix of powder wire (600–1000 HV100). Under the conditions of boundary friction, a friction couple formed by a (Fe–Cr–B) + Sv08 powder wire and a BrS-30 counterbody has the best tribological characteristics. The elevated wear resistance of the coatings is explained by the presence of large amounts of iron and boron oxides. We analyze the properties of the coatings under the conditions of boundary friction. The friction coefficient of steel increases from 0.018 under 1 МРа to 0.038 under 10 Ра. This is higher than for a friction couple formed by a coating sprayed from Sv08 and PW (Fe–Cr–B) electrode wires and BrS-30 by 50–70%. The abrasive wear resistance of the coatings sprayed from composite wires with fixed abrasive becomes 2.1 times higher as compared with ShKh15 steel. [ABSTRACT FROM AUTHOR]

Based on lithium aluminosilicate glass, the composition of glass was optimized by replacing SiO2 with B2O3, and the influence of glass composition on structure and performance was studied. With the increase in B2O3 concentrations from 0 to 6.5 mol%, Al2O3 always existed in the form of four-coordinated [AlO4] in the network structure, and B2O3 mainly entered the network in the form of four-coordinated [BO4]. The content of Si-O-Si linkages (Q4(0Al)) was always dominant. The incorporation of boron oxide improved the overall degree of polymerization and connectivity of the lithium aluminosilicate glass network structure. An increase in the degree of network polymerization led to a decrease in the thermal expansion coefficient of the glass and an increase in Vickers hardness and density. The durability of the glass in hydrofluoric acid and NaOH and KOH solutions was enhanced overall. [ABSTRACT FROM AUTHOR]

Bioactive glass coatings can improve the osteo integration of metallic implants with the host tissue, thereby increasing their lifespan and overall success rate. However, complex composition‐structure‐property relations in phosphosilicate‐based bioactive glasses make experimental determination of these relations and related composition design of bioactive coatings challenging. By applying molecular dynamics (MD)‐based atomistic simulations with recently developed effective potentials, this work addresses the challenge by using a material genome approach to obtain the composition and structure effects on various key properties for bioactive coating applications. A series of potential bioactive glass compositions were studied and the composition effects on the mechanical and thermal properties that are critical to these bioactive glasses as a coating to metallic implants were calculated. Particularly, by varying the level of B2O3 to SiO2 substitutions, the effect of composition on various key properties was elucidated. It was found that by using cation in a 1 to 1 ratio (BO3/2 to SiO2) instead of the commonly used substitutions (B2O3 to SiO2), the composition effect can be more clearly expressed and, hence, recommended in future composition designs. Together with careful structural analysis, the origin of property changes can be elucidated. The atomistic computer simulation‐based approach is, thus, an effective way to guide future bioactive glass designs for bioactive coatings and other applications. [ABSTRACT FROM AUTHOR]

Results of receiving a diborid of magnesium are given in work by magniathermal oxidation of boron composite compounds at different argon pressures and temperatures. The relevance of a research is proved by superconducting properties of magnesium diboride. Synthesis of magnesium diboride itself accelerates, due to wall burning and thermal explosion of exothermic mixture of the reaction products of magniathermal. It is shown that the use of SHS method at high argon pressure and temperature allows to obtain magnesium diboride of high purity.

Boron-rich waste causes numerous environmental problems when discharged directly into the environment. Here, various quantities of boron oxide (B _2 O _3 ) were added to calcium sulfoaluminate (C _4 A _3 $) during the sintering process to demonstrate a potential use of boron-rich waste. The microstructure and hydration performance of C _4 A _3 $ with various B _2 O _3 contents were investigated with scanning electron microscopy, x-ray diffraction, isothermal conduction calorimetry, thermogravimetric studies and compressive strength tests. B _2 O _3 -doped C _4 A _3 $ had a larger grain size than the pure phase; and were surrounded by amorphous phases. The presence of B _2 O _3 was shown to promote the phase transition process through which C _4 A _3 $ changes from the orthorhombic to the cubic structure; and the substitution of Al ^3+ for B ^3+ in AlO _4 tetrahedra was surveyed by structural refinements. As the B _2 O _3 content increased, the induction period of C _4 A _3 $ increased while the hydration rate decreased because of the amorphous phases around the C _4 A _3 $. However, the hydration degree of doped C _4 A _3 $ increased due to the slower reaction rate. Thus, when an appropriate amount of B _2 O _3 was added to the C _4 A _3 $ during sintering, a significant improvement in the compressive strength of pastes was observed.

Porous Al5BO9 is a promising high‐temperature wave‐transparent material. However, method for the preparation of this material is not readily available. Herein, porous Al5BO9 ceramics with controlled porosity and small volume shrinkage are successfully prepared by using Al2O3 and B2O3 as starting materials without pore formers. The SEM and pore size distribution studies show that the as‐prepared porous Al5BO9 ceramics exhibit a uniform pore structure and a narrow pore size distribution. Intriguingly, simply adjusting the densities of the green bodies, the density and porosity of the porous Al5BO9 ceramics can be controlled. The pore‐forming mechanism is presumed to be a combination of boron oxide volatilization during the high‐temperature synthesis and lap of elongated grains. Porous Al5BO9 ceramics have good high‐temperature stability, which can maintain dimensional and composition stability up to 1673 K. The compressive strength can reach 211 MPa at 32.4% porosity and the dielectric constant can be as low as 3.02 at 43.2% porosity. In addition, the dielectric constant and loss tangent keep almost unchanged with temperature. [ABSTRACT FROM AUTHOR]

It is shown that the B3+ element is able to incorporate into the facets of oxygen tetrahedra of LiNbO3 crystal structure ( [BO3]3- group) in a trace amounts ( ≈10^(-4) wt. %). In this case, boron noticeably distorts the anion sublattice of the crystal, changing the lengths of the bonds, increasing the ordering of structural units of the cation sublattice. At the same time, boron changes the polarizability of the oxygen-octahedral MeO6 clusters ( Me — Li, Nb ) which determines the ferroelectric and nonlinear optical properties of the crystal.

Here, boric acid (H3BO3) and its dewatered form, boron trioxide (B2O3) were tested as catalysts for hydrogen (H2) evolution in the methanolysis of sodium borohydride (NaBH4) in methanol. Parameters such as catalyst types and their amounts, NaBH4 concentration, and the reaction temperature affecting the hydrogen generation rate (HGR) were studied. It has been found that H3BO3 and B2O3 catalyzed methanolysis reaction of NaBH4 follow up first-order kinetics relative to the concentration of NaBH4. Furthermore, the conversion and activity of these catalysts were examined to determine their performance in ten consecutive use. Interestingly, H3BO3 and B2O3 have demonstrated superior catalytic performances in methanolysis of NaBH4 comparing to the studies published in literature with the activation energy of respectively 22.08 kJ.mol-1, and 23.30 kJ.mol-1 in H2 production. The HGR was calculated as 6481 mL.min-1.g-1 and 5163 mL.min-1.g-1 for H3BO3 and B2O3 catalyst, respectively for 50 mg catalyst at 298 K. These results are comparably better than most metal nanoparticle catalysts used for H2 production in addition to the naturally occurring boron-based environmentally friendliness of these materials. [ABSTRACT FROM AUTHOR]

The alumina ceramics were joined by spark plasma sintering (SPS) at 1000 °C for 10 min under an applied pressure of 30 MPa using the screen-printed B 2 O 3 as the joining material. The thickness of the interlayers after joining was approximately 5 μm. The average shear strength measured of the joint was 141.9 ± 4.1 MPa, which was the highest value of joined alumina ceramic using B 2 O 3 only ever reported in the open literatures. The presence of Al 4 B 2 O 9 whiskers formed by the in-situ reaction between B 2 O 3 and Al 2 O 3 was assumed to contribute to the strong joint. A sample with extra holding at 400 °C for 10 min before 1000 °C was conducted to investigate the suppression effect of joining parameter on the volatilization of B 2 O 3. The average shear strength was 104.2 ± 9.4 MPa, which implied that low-temperature holding step promoted rather than suppressed B 2 O 3 volatilization, resulting in lower shear strength. [ABSTRACT FROM AUTHOR]