B2 O3 Research Articles

Boric Acid as a Coupling Agent for Preparation of Phenolic Resin Containing Boron and Silicon with Enhanced Char Yield.

In this study, an innovative, facile, and low-cost method is developed to prepare phenolic resin (PR) containing boron and silicon (BSiPR). BSiPR is synthesized by a solvent-free, one-pot method using boric acid as the coupling agent instead of silane, and methyltriethoxysilane as the silicon source. The results show that boron and silicon elements are introduced into PR via BOC and BOSi structures. The char yield of the resulting resin at 800°C is improved to 76%. The reasons for higher char yield are investigated. The formation of BOC can reduce the content of phenolic hydroxyl, which helps to decrease the weight loss. B2 O3 is also formed at 400°C, and it can prevent the release of carbon oxides. Moreover, thermally stable BOSi and SiO structures remain stable during the pyrolysis. In addition, the mechanical and ablative properties of fiber-reinforced composites are also enhanced.

N-Doped C@Zn3 B2 O6 as a Low Cost and Environmentally Friendly Anode Material for Na-Ion Batteries: High Performance and New Reaction Mechanism.

Na-ion batteries (NIBs) are ideal candidates for solving the problem of large-scale energy storage, due to the worldwide sodium resource, but the efforts in exploring and synthesizing low-cost and eco-friendly anode materials with convenient technologies and low-cost raw materials are still insufficient. Herein, with the assistance of a simple calcination method and common raw materials, the environmentally friendly and nontoxic N-doped C@Zn3 B2 O6 composite is directly synthesized and proved to be a potential anode material for NIBs. The composite demonstrates a high reversible charge capacity of 446.2 mAh g-1 and a safe and suitable average voltage of 0.69 V, together with application potential in full cells (discharge capacity of 98.4 mAh g-1 and long cycle performance of 300 cycles at 1000 mA g-1 ). In addition, the sodium-ion storage mechanism of N-doped C@Zn3 B2 O6 is subsequently studied through air-insulated ex situ characterizations of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared (FT-IR) spectroscopy, and is found to be rather different from previous reports on borate anode materials for NIBs and lithium-ion batteries. The reaction mechanism is deduced and proposed as: Zn3 B2 O6 + 6Na+ + 6e- ⇋ 3Zn + B2 O3 ∙ 3Na2 O, which indicates that the generated boracic phase is electrochemically active and participates in the later discharge/charge progress.

Boron Embedded in Metal Iron Matrix as a Novel Anode Material of Excellent Performance.

Boron, the most ideal lithium-ion battery anode material, demonstrates highest theoretical capacity up to 12 395 mA h g-1 when forming Li5 B. Furthermore, it also exhibits promising features such as light weight, considerable reserves, low cost, and nontoxicity. However, boron-based materials are not in the hotspot list because Li5 B may only exist when B is in atomically isolated/dispersed form, while the aggregate material can barely be activated to store/release Li. At this time, an ingenious design is demonstrated to activate the inert B to a high specific capacity anode material by dispersing it in a Fe matrix. The above material can be obtained after an electrochemical activation of the precursors Fe2 B/Fe and B2 O3 /Fe. The latter harvests the admirable capacity, ultrahigh tap density of 2.12 g cm-3 , excellent cycling stability of 3180 mA h cm-3 at 0.1 A g-1 (1500 mA h g-1 ) after 250 cycles, and superlative rate capability of 2650 mA h cm-3 at 0.5 A g-1 , 2544 mA h cm-3 at 1.0 A g-1 , and 1696 mA h cm-3 at 2.0 A g-1 . Highly conductive matrix promoted reversible Li storage of boron-based materials might open a new gate for advanced anode materials.

Correlating the Surface Basicity of Metal Oxides with Photocatalytic Hydroxylation of Boronic Acids to Alcohols.

Photoredox catalysis provides opportunities in harnessing clean and green resources such as sunlight and O2 , while the acid and base surface sites of metal oxides are critical for industrial catalysis such as oil cracking. The contribution of metal oxide surfaces towards photocatalytic aerobic reactions was elucidated, as demonstrated through the hydroxylation of boronic acids to alcohols. The strength and proximity of the surface base sites appeared to be two key factors in driving the reaction; basic and amphoteric oxides such as MgO, TiO2 , ZnO, and Al2 O3 enabled high alcohol yields, while acidic oxides such as SiO2 and B2 O3 gave only low yields. The reaction is tunable to different irradiation sources by merely selecting photosensitizers of compatible excitation wavelengths. Such surface complexation mechanisms between reactants and earth abundant materials can be effectively utilized to achieve a wider range of photoredox reactions.

Structure and Correlation Between the Fraction of Structural Units and Bond Angle Distribution in Liquid B2 O3 Under Compression

Structure of network-forming liquid B2 O3 is investigated by Molecular dynamics simulation (MDS) at 2000K and in the 0-40 GPa pressure range (corresponding to the 1.71-3.04 g/cm3 density range). Results indicate that network structure of liquid B2 O3 comprises of basic structural units BO3 and BO4 . The topology and size of BO3 and BO4 units at different densities are identical. The O-B-O and B-O-B partial bond angle distributions (BADs) can be determined through the fraction of BO3 and BO4 units. Furthermore, the total BADs are directly related to the partial BADs and the fraction of structural units. It means the fraction of units BOX (X = 3,4) and units OBy (y = 2,3) can be determined from the experimental BADs. The spatial distribution of BO3 and BO4 units is not uniform but forming clusters of BO3 and BO4 . This leads to the polyamorphism in liquid B2 O3 . It also shows that the dynamical heterogeneity in liquid B2 O3 due to the lifetimes of BO3 and BO4 units are very different. The structural heterogeneity is origin of spatially heterogeneous dynamics in liquids B2 O3 .

THERMODYNAMICS OF OXYGEN SOLUTIONS IN BORON-CONTAINING Fe – Ni MELTS

Fe – Ni alloys are widely used in modern technology. Boron is one of the alloying components in these alloys. Oxygen is one of the harmful impurities in Fe – Ni alloys, it presents in the metal in dissolved form or in the form of oxide nonmetallic inclusions. The presence of oxygen in these alloys degrades their service properties. The study of thermodynamics of the oxygen solution in boron-containing Fe – Ni melts is of considerable interest for the practice of such alloys production. Thermodynamic analysis of oxygen solutions in boroncontaining Fe – Ni melts has been carried out. The equilibrium constant of interaction of boron and oxygen dissolved in the Fe – Ni melts, the activity coefficients at infinite dilution, and the interaction parameters characterizing these solutions were determined for melts of different composition. In the interaction of boron with oxygen in Fe – Ni melts, the oxide phase, in addition to B2 O3 , contains FeO and NiO. Values of the mole fractions of B2 O3 , FeO and NiO in the oxide phase for different boron concentrations in Fe – Ni melts were calculated at 1873 K. In the case of an iron melt at low boron contents, the mole fraction of boron oxide is ~0.1. As the content of nickel and boron increases in the melts, the mole fraction of boron oxide in the oxide phase increases and, in the case of pure nickel, is close to unity. Dependences of the oxygen solubility on the contents of nickel and boron in the studied melts were calculated. With increasing nickel content in melt deoxidation ability of chromium increases significantly. The oxygen solubility curves in boron-containing Fe – Ni melts pass through a minimum whose position shifts to the higher boron content with an increase in the nickel content in melt. Boron contents in minimum points on the oxygen solubility curves and the corresponding minimum oxygen concentrations were determined.

Emission analysis of Tb3+ -and Sm3+ -ion-doped (Li2 O/Na2 O/K2 O) and (Li2 O + Na2 O/Li2 O + K2 O/K2 O + Na2 O)-modified borosilicate glasses.

Four series of borosilicate glasses modified by alkali oxides and doped with Tb3+ and Sm3+ ions were prepared using the conventional melt quenching technique, with the chemical composition 74.5B2 O3 + 10SiO2 + 5MgO + R + 0.5(Tb2 O3 /Sm2 O3 ) [where R = 10(Li2 O /Na2 O/K2 O) for series A and C, and R = 5(Li2 O + Na2 O/Li2 O + K2 O/K2 O + Na2 O) for series B and D]. The X-ray diffraction (XRD) patterns of all the prepared glasses indicate their amorphous nature. The spectroscopic properties of the prepared glasses were studied by optical absorption analysis, photoluminescence excitation (PLE) and photoluminescence (PL) analysis. A green emission corresponding to the 5 D4 → 7 F5 (543nm) transition of the Tb3+ ions was registered under excitation at 379nm for series A and B glasses. The emission spectra of the Sm3+ ions with the series C and D glasses showed strong reddish-orange emission at 600nm (4 G5/2 →6 H7/2 ) with an excitation wavelength λexci = 404nm (6 H5/2 →4 F7/2 ). Furthermore, the change in the luminescence intensity with the addition of an alkali oxide and combinations of these alkali oxides to borosilicate glasses doped with Tb3+ and Sm3+ ions was studied to optimize the potential alkali-oxide-modified borosilicate glass.

The First Alkaline-Earth Fluorooxoborate Ba[B4 O6 F2 ]-Characterisation and Doping with Eu2.

The very first alkaline-earth fluorooxoborate Ba[B4 O6 F2 ] was synthesised by solid state methods starting from Ba(BF4 )2 , β-BaB2 O4 , and B2 O3 . The crystal structure derived from single-crystal X-ray diffraction (P21 /n, a=6.6384(2) Å, b=7.6733(3) Å, c=11.3385(4) Å, β=91.281(2)°, Z=4, Rint =0.0269, R1 =0.018, wR2 =0.034) comprises layers of BO3 F tetrahedra condensed through triangular BO3 units according to the descriptor 2Δ2□:<Δ2□>Δ. The extraordinary thirteen-fold coordination of barium by oxygen and fluorine leads to interesting optical properties of a sample doped with divalent europium, where a 4f→4f emission was recorded around 359 nm together with a broad emission band of a 5d→4f emission peaking at 366 nm. The compound is further characterised by IR-, Raman-, and solid-state NMR-spectroscopic methods. Moreover, DFT calculations as well as TGA and DSC measurements were performed.

Recovery of boron from high-boron iron concentrate using reduction roasting and magnetic separation

The comprehensive utilization of abundant high-boron iron concentrate is of particular significance to China, and the high-boron iron concentrate has not yet been utilized as a source for boron at an industrial scale due to its complex mineralogy and fine mineral dissemination. An innovative method was proposed for recovery of boron and iron from high-boron iron concentrate by reduction roasting and magnetic separation. The effects of reduction temperature and roasting time were investigated and their optimum conditions were determined. The mineralogical changes during roasting were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the pyrrhotite (FeS) contained in the high-boron iron concentrate and the new-formed FeS-Fe solid solution softened or melted at high temperatures owing to their low melting points, and then decreased the metallic iron ratio and accelerated the growth of metallic iron particles. Meanwhile, the magnetite and szaibelyite were converted into metallic iron and suanite, respectively. Consequently, boron was readily enriched into the non-magnetic product and the metallic iron was aggregated to the magnetic concentrate by magnetic separation. Boron recovery of 88. 6% with corresponding B2 O3 content of 14. 5% and iron recovery of 95. 1% with an iron grade of 92. 7% were achieved when high-boron iron concentrate was reduced at 1125 °C for 150 min. Besides, the boron reactivity of the boron-rich non-magnetic product was up to 80. 8%.

Effect of compositions and additives content on crystallization behavior of Ti-rich phase from Ti-bearing blast furnace slag

The precipitation behavior of Ti-rich phases from high Ti-bearing blast furnace (Ti-BF) slag was studied with (Mg + Al)/(Ca + Si) ratio and B2 O3 concentration range from 0.37 to 0.67 and from 0 to 4%, respectively. Scanning Electron Microscope (SEM) and Electron probe X-ray microanalysis (EPMA) were used for determining crystal behavior of the slags quenched from high temperatures and the compositions of the crystals. The results showed that two main phases, which were perovskite and anosovite can precipitate during the experimental process. Specifically speaking, when the content of B2 O3 was 2.0% and (Mg + Al)/(Ca + Si) ratio was 0.47, the precipitated crystals of the melt slags transformed from perovskite to anosovite at the temperature of 1320 °C. With the increase of B2 O3 content from 0 to 4.0%, the volume fraction of anosovite enhanced from 0 to 8.3% correspondingly. The increasing of (Mg + Al)/(Ca + Si) ratio and B2 O3 were favorable to form anosovite while decrease (Mg + Al)/(Ca + Si) ratio was beneficial to precipitate perovskite.

Synthesis, Crystal Structure, and Properties of Bi3 TeBO9 or Bi3 (TeO6 )(BO3 ): A Non-Centrosymmetric Borate-Tellurate(VI) of Bismuth.

Pale-yellow single crystals of the new borate tellurate(VI) Bi3 TeBO9 were obtained by reaction of stoichiometric amounts of Bi2 O3 , B2 O3 , and Te(OH)6 at 780 °C. The non-centrosymmetric crystal structure (P63 , Z=2, a=8.7454(16), c=5.8911(11) Å, 738 refl., 43 param, R1=0.037, wR2=0.093) contains isolated trigonal-planar BO3 units and nearly undistorted TeO6 octahedra. The Bi3+ cations are located in between in octahedral voids. The BiO6 octahedra are significantly distorted to a [3+3] pattern (2.25/2.50 Å) due to the ns2 configuration. According to the structural features, the formula can be written as Bi3 (TeO6 )(BO3 ). Alternatively, the structure can also be described as hcp of oxygen with TeVI and BiIII in octahedral voids and BIII in trigonal- planar voids. The vibrational spectra show the typical features of BO3 and TeO6 units with a significant 10 B/11 B isotopic splitting of the IR-active B-O valence mode (1248 and 1282 cm-1 ). The UV/Vis spectrum shows an optical band edge with an onset around 480 nm (2.6 eV). MAS-NMR spectra of 11 B show an anisotropic signal with a quadrupole coupling constant of CQ =2.55 MHz. and a very small deviation from rotational symmetry (η=0.2). The isotropic chemical shift is 20.1 ppm. The second harmonic generation (SHG) test was positive with an activity comparable to potassium dihydrogen phosphate (KDP). Bi3 TeBO9 decomposes in air at 825 °C to Bi2 TeO5 .

Lasing transition at 1.06 μm emission in Nd3+‐doped borate‐based tellurium calcium zinc niobium oxide glasses for high‐power solid‐state lasers

The spectroscopic properties of Tellurium Calcium Zinc Niobium oxide Borate (TCZNB) glasses of composition (in mol%) 10TeO2 +15CaO+5ZnO+10 Nb2 O5 +(60 - x)B2 O3 +Nd2 O3 (x=0.1, 0.5, 1.0 or 1.5mol%) have been investigated experimentally. The three phenomenological intensity parameters Ω2 , Ω4, Ω6 have been calculated using the Judd-Ofelt theory and in turn radiative properties such as radiative transition probabilities, emission cross-sections, branching ratios and radiative lifetimes have been estimated. The trend found in the JO intensity parameter is Ω2 >Ω6 >Ω4 If Ω6 >Ω4 , the glass system is favourable for the laser emission 4 F3/2 →4 I11/2 in the infrared (IR) wavelength. The experimental values of branching ratio of 4 F3/2 →4 I11/2 transition indicate favourable lasing action with low threshold power. The evaluated total radiative transition probabilities (AT ), stimulated emission cross-section (σe ) and gain bandwidth parameters (σe ×Δλp ) were compared with earlier reports. An energy level analysis has been carried out considering the experimental energy positions of the absorption and emission bands.

Effect of boron oxide addition on the viscosity-temperature behaviour and structure of phosphate-based glasses.

In this study, nine phosphate-based glass formulations from the system P2 O5 -CaO-Na2 O-MgO-B2 O3 were prepared with P2 O5 content fixed as 40, 45 and 50 mol%, where Na2 O was replaced by 5 and 10 mol% B2 O3 and MgO and CaO were fixed to 24 and 16 mol%, respectively. The effect of B2 O3 addition on the viscosity-temperature behaviour, fragility index and structure of the glasses was investigated. The composition of the glasses was confirmed by ICP-AES. The viscosity-temperature behaviour of the glasses were measured using beam-bending and parallel -plate viscometers. The viscosity of the glasses investigated was found to shift to higher temperature with increasing B2 O3 content. The kinetic fragility parameter, m and F1/2 , estimated from the viscosity curve were found to decease with increasing B2 O3 content. The structural analysis was achieved by a combination of Fourier transform infrared spectroscopy and solid state nuclear magnetic resonance. 31 P solid-state magic-angle-spinning nuclear magnetic resonance (MAS-NMR) showed that the local structure of the glasses changes with increasing B2 O3 content. As B2 O3 was added to the glass systems, the phosphate connectivity increases as the as the Q1 units transforms into Q2 units. The 11 B NMR results confirmed the presence of tetrahedral boron (BO4 ) units for all the compositions investigated. Structural analysis indicates an increasing level of cross-linking with increasing B2 O3 content. Evidence of the presence of P-O-B bonds was also observed from the FTIR and 31 P NMR analysis. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 764-777, 2017.

Effect and mechanism of B2O3on apparent viscosity of slag during smelting of vanadium-titanium magnetite in the Blast Furnace

Considering the low fluidity and the difficulties in separating high Ti-bearing blast furnace slag from hot metal, the effect of B2 O3 on apparent viscosity under argon atmosphere was studied from 1340 °C to 1475 °C using Brookfield Rotational Viscometer, Metallographic Microscope, et al. The results showed that the addition of B2 O3 could decrease melting temperature of high Ti-bearing blast furnace slag and increased its fluidity. With increasing the amount of B2 O3 from 0 to 3%, mass fraction of perovskite in high Ti-bearing blast furnace slag gradually decreased, but four times the mass fraction of anosovite. The Ti(C,N) appeared enrichment in the high Ti-bearing blast furnace slag, and the enrichment changed with the addition of B2 O3 increasing.

Thermodynamic modelling of liquids: CALPHAD approaches and contributions from statistical physics

We describe current approaches to thermodynamic modelling of liquids for the CALPHAD method, the use of available experimental methods and results in this type of modelling, and considerations in the use of atomic‐scale simulation methods to inform a CALPHAD approach. We begin with an overview of the formalism currently used in CALPHAD to describe the temperature dependence of the liquid Gibbs free energy and outline opportunities for improvement by reviewing the current physical understanding of the liquid. Brief descriptions of experimental methods for extracting high‐temperature data on liquids and the preparation of undercooled liquid samples are presented. Properties of a well‐determined substance, B2 O3, including the glass transition, are then discussed in detail to emphasize specific modelling requirements for the liquid. We then examine the two‐state model proposed for CALPHAD in detail and compare results with experiment and theory, where available. We further examine the contributions of atomic‐scale methods to the understanding of liquids and their potential for supplementing available data. We discuss molecular dynamics (MD) and Monte Carlo methods that employ atomic interactions from classical interatomic potentials, as well as contributions from ab initio MD. We conclude with a summary of our findings.

ChemInform Abstract: Acentric Polyborate, Li3[B8O12(OH)3], with a New Type of Anionic Layer and Li Atoms in the Cavities.

AbstractSingle crystals of Li3[B8O12(OH)3] are obtained by hydrothermal synthesis of a mixture with a molar ratio of PbCO3:Bi2O3:LiIO3:B2 O3:SiO2 = 1:1:2:3:1 (autoclave, 270 °C, 71 bar, 18—20 d).

Fabrication and Evaluation of Osteoblastic Differentiation of Human Mesenchymal Stem Cells on Novel CaO-SiO2-P2O5-B2O3Glass-Ceramics

Apatite-wollastonite glass-ceramics have high mechanical strength, and CaO-SiO2 -B2 O3 glass-ceramics showed excellent bioactivity and high biodegradability. A new type of CaO-SiO2 -P2 O5 -B2 O3 system of bioactive glass-ceramics (BGS-7) was fabricated, and the effect and usefulness was evaluated via bioactivity using simulated body fluid and human mesenchymal stem cells (hMSCs). The purpose of this study was to compare BGS-7 and hydroxyapatite (HA) using hMSCs in order to evaluate the bioactivity of BGS-7 and its possibility as a bone graft extender. Alkaline phosphatase (ALP) staining, ALP activity, cell proliferation 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay, Alizarin Red-S (AR-S) staining, calcium levels, the mRNA expression of ALP, osteocalcin, osteopontin, and runt-related transcription factor 2 (runx-2) using reverse-transcription polymerase chain reaction (RT-PCR) and the protein expression of osteocalcin and runx-2 using Western blot were measured by transplanting hMSC onto a tissue culture plate, HA, and BGS-7. The ALP staining and AR-S staining of BGS-7 was greater than that of HA and control. The ALP value of BGS-7 was significantly higher than that of HA and control. The MTS results showed that BGS-7 had a higher value than the groups transplanted onto HA and control on day 15. The calcium level was higher than the control in both HA and BGS-7, and was especially high in BGS-7. There were more mineral products on BGS-7 than on the HA when analyzed by scanning electron microscopy. The mRNA expression of ALP, osteopontin, osteocalcin, and runx-2 were higher on BGS-7 than on HA and the control when analyzed by RT-PCR. The relative gene expression of osteopontin and runx-2 were found to be higher on BGS-7 than on HA and the control by Western blot. Accordingly, it is predicted that BGS-7 would have high biocompatibility and good osteoconductivity, and presents a possibility as a new bone graft extender.

Facile Synthesis of Large‐Area Ultrathin Hexagonal BN Films via Self‐Limiting Growth at the Molten B2O3 Surface

A self-limiting growth process based on the interface-controlled reaction of molten boron oxide (B2 O3 ) with ammonia (NH3 ) is demonstrated for the facile and lost-cost synthesis of ultrathin (20-30 nm) crystalline hexagonal boron nitride (h-BN) films over large areas. The as-grown h-BN films are of high quality, being densely continuous, uniform and smooth, and highly transparent over a broad wavelength range.

Effect of Additives on Melting Point of LATS Refining Ladle Slag

To avoid slag sticking on the ladle immersion cover during the LATS refining and alloying process, the effect of Al2O3 on the melting point of the ladle slag was studied and the additives including CaF2, B2 O3, Li2 O, and CaO were used to decrease the melting point of the ladle slag. The melting point was measured using the hemisphere method. The results show that the addition of Al2 O3 to the ladle slag increases the melting point. The fluxing action is not remarkable if only CaF2 or CaO is used as the additive. The fluxing action of the composite additive obtained by the mixing of CaO and CaF2 in the mass proportion of ΩCaO: ΩCaF2 = 2:1 is preferred. The fluxing action of B2 O3 is also notable. When the B2 O3 content in mass percent is in the range from 2% to 10%, the corresponding melting point is 1 380 °C to 1 290 °C. The fluxing action of Li2O is the most remarkable. When the Li2 O content is up to 5%, the melting point of the slag is lower than 1 300 °C.

Photoluminescence Properties of Ba-Substituted SrAl&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt;:Eu Phosphor

The synthesis of Sr1-XBaXAl2O4 :Eu 2+ (x = 0, 0.1, 0.2 and 0.3 mol) phosphor and its properties of photoluminescence and long-phosphorescence were investigated as a function of sintering condition. The single phase of SrAl2O4 was obtained by sintering the mixtures of SrCO3, BaCO3, Eu2 O3, Al2O3 and 3wt% B2 O3 powders over 1100°C in Ar/H2 atmosphere. Stuctural properties were analyzed by a X-ray diffractometer, microstructural properties by a SEM, and photoluminescent properties by a PL measuring system. The optimum sintering condition for the long-phosphorescent phosphor of Sr1-XBaXAl2O4:Eu2+ was found at 1400 °C. Substitution of Ba about 0.2mol in SrAl2O4 :Eu 2+ enhanced the photoluminescence and long-phosphorescence.