Amount Of Boron Research Articles

The effect of boron and zirconium on microstructure and tensile properties of the wrought nickel-based superalloy ATI 718Plus

In the present study, the effect of boron and zirconium on the microstructural characteristics, ductility and the tensile strength of the wrought nickel-based superalloy 718Plus were investigated. In this regard, five alloys with different amounts of boron 0.00–0.016wt%) and zirconium 0.0–0.1wt%) were cast via the vacuum induction melting and then purified via the vacuum arc remelting. Microstructural observations were carried out through optical and scanning electron microscopes and phase analysis was performed by x-ray diffraction analysis. The tensile test was carried out at room temperature and 704°C on the alloys. The results showed a slight effect of boron and zirconium on grain size while they had significant effect on the amount and the stability of the delta phase. These elements increase the lattice mismatch and the elastic strain between the γ and γ′ phases. Boron and zirconium increased the ductility at room temperature by 10% and 12% and at the 704°C by 8% and 5%, respectively. The effect of these elements on the strength at room temperature was negligible, while at 704°C, boron and zirconium increased the yield strength by 17% and 16% and the ultimate strength by 8% and 7%, respectively. The improved cohesion and strength of the grain boundaries and an increase in delta phase and the elastic strain between γ and γ′ phases are the most important causes for improving the ductility and strength of the alloy 718Plus in the presence of boron and zirconium.

Fine Structure Study of the Plasma Coatings B4C-Ni-P

The article considers structure of coatings formed of the B4C-Ni-P powder. The coatings were deposited using air-plasma spraying with the unit for annular injection of powder. The pipes from steel 20 (0.2 % C) were used as a substrate. The structure and phase composition of the coatings were studied by optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. It is shown that high-density composite coatings consisting of boron carbide particles distributed in the nickel boride metal matrix are formed using air-plasma spraying. The areas with round inclusions characterized by the increased amount of nickel, phosphorus and boron are located around the boron carbide particles. Boron oxides and nickel oxides are also present in the coatings. Thin interlayers with amorphous-crystalline structure are formed around the boron carbide particles. The thickness of these interlayers does not exceed 1 μm. The metal matrix material represents areas with nanocrystalline structure and columnar crystals.

Nanostructured boron compounds for cancer therapy

Abstract Nanostructured boron compounds have emerged as one of the promising frontiers in boron chemistry. These species possess unique physical and chemical properties in comparison with classical small boron compounds. The nanostructured boron composites generally have large amounts of boron contents and thus have the potential to deliver significant amount of boron to the tumor cells, that is crucial for boron neutron capture therapy (BNCT). In theory, BNCT is based on a nuclear capture reaction with the 10B isotope absorbing a slow neutron to initiate a nuclear fission reaction with the release of energetic particles, such as lithium and helium (α particles), which travel the distance of around nine microns within the cell DNA or RNA to destroy it. The recent studies have demonstrated that the nanostructured boron composites can be combined with the advanced targeted drug delivery system and drug detection technology. The successful combination of these three areas should significantly improve the BNCT in cancer treatment. This mini review summarizes the latest developments in this unique area of cancer therapy.

Inclusion Measurements in Al–Si Foundry Alloys Using Qualiflash and Prefil Filtration Techniques

Qualiflash is a quick method of assessing the melt cleanliness of foundry Al–Si alloys over a wide range of Si contents up to 17 wt%. It has an immediate response in measuring the quantity of oxides and non-metallic inclusions. Improving the melt cleanliness moves the Quality Temperature Index line toward lower Q values. Prefil curves demonstrate very good sensitivities to the variations in the melt treatment conditions. The filtration rate is greatly affected by grain refiner addition. The highest curve is displayed by the alloy without grain refiner addition. The filtration rate progressively decreases with increasing amount of grain refiner. When the total amount of boron in the grain refiner added to the melt reaches 60 ppm, the filtration rate is approximately nil. The overall error on the Prefil curve is ± 9% at a level of confidence of 95% at any time during the filtration.

Effects of Variable Boron Concentration on the Properties of Superhard Tungsten Tetraboride.

Tungsten tetraboride is an inexpensive, superhard material easily prepared at ambient pressure. Unfortunately, there are relatively few compounds in existence that crystallize in the same structure as tungsten tetraboride. Furthermore, the lack of data in the tetraboride phase space limits the discovery of any new superhard compounds that also possess high incompressibility and a three-dimensional boron network that withstands shear. Thus, the focus of the work here is to chemically probe the range of thermodynamically stable tetraboride compounds with respect to both the transition metal and the boron content. Tungsten tetraboride alloys with a variable concentration of boron were prepared by arc-melting and investigated for their mechanical properties and thermal stability. The purity and phase composition were confirmed by energy dispersive X-ray spectroscopy and powder X-ray diffraction. For variable boron WBx, it was found that samples prepared with a metal to boron ratio of 1:11.6 to 1:9 have similar hardness values (∼40 GPa at 0.49 N loading) as well as having a similar thermal oxidation temperature of ∼455 °C. A nearly single phase compound was successfully stabilized with tantalum and prepared with a nearly stoichiometric amount of boron (4.5) as W0.668Ta0.332B4.5. Therefore, the cost of production of WB4 can be decreased while maintaining its remarkable properties. Insights from this work will help design future compounds stable in the adaptable tungsten tetraboride structure.

Highly Condensed Boron Cage Cluster Anions in 2D Carrier and Its Enhanced Antitumor Efficiency for Boron Neutron Capture Therapy

AbstractAn attempt is made to apply layered double hydroxide (LDH) as a boron delivery carrier for boron neutron capture therapy (BNCT), which needs a sufficient amount of boron in tumor cells for its successful administration. To meet this requirement, a nanohybrid (BSH‐LDH), mercaptoundecahydro‐closo‐dodecaborate (BSH) anionic molecules in LDH, is developed as a boron delivery system. The cellular boron content upon permeation of BSH‐LDH nanoparticles (42.4 µg 10B 10−6 cells) in U87 glioblastoma cell line is found to be ≈2000 times larger than the minimum boron requirement (≈0.02 µg 10B 10−6 cells) for BNCT and also orders of magnitude higher than the previous results (0.2–1.5 µg 10B 10−6 cells) by those applied with other targeting strategies, and eventually results in excellent neutron capture efficiency even under such low dose (30 µg 10B mL−1) and weak irradiation (1 × 1012 n cm−2 corresponding to 20 min) condition. According to the biodistribution studies in xenograft mice model, the tumor‐to‐blood ratio of BSH in the BSH‐LDH‐treated‐group is found to be 4.4‐fold higher than that in the intact BSH treated one in 2 h after drug treatment. The present BNCT combined with boron delivery system provides a promising integrative therapeutic platform for cancer treatment.

Theoretical analysis of ammonium-perchlorate based composite propellants containing small size particles of boron

One of the main goals for the scientific/ military rocket industry is to increase the operational burning time, thus the specific impulse. New homogeneous and heterogeneous propellants were tested and metallic fuels were added in the mixture to obtain best performance. To study heterogeneous propellant, containing large amount of fine boron and ammonium perchlorate, it is appropriate to estimate the combustion products to evaluate/obtain the values of the specific impulse, density, Mach number and mass flow of the mixture. Several composite propellant mixtures, ammonium perchlorate, nitramides (RDX – Cyclotrimethylene trinitramide), were defined with or without addiction of small particles of Boron and modeled. The energetic properties of boron and progress of boron particles on the burning surface of the ammonium perchlorate based composite propellants was modeled used a numerical algorithm. This paper reports the analysis of the influence of boron in the performance parameters for ammonium perchlorate based composite propellants.

Foamed polyurethane plastics of reduced flammability

ABSTRACTIn this study, modified foamed polyurethane materials were obtained with the use of new polyols. The polyols were synthesized by the reaction of N,N′‐bis(2‐hydroxyethyl)oxamide esterified with boric acid and various excesses of ethylene carbonate. Thus, poly(ethylene glycol)s with incorporated oxamide and borate groups containing different amounts of boron and nitrogen were obtained. On the basis of these new polyols, rigid polyurethane foams were produced. They contained 0.8–1.2 wt % boron and 7.9–8.5 wt % nitrogen. The resulting foams showed reduced flammability, as determined on the basis of the measurements of the oxygen index and horizontal and vertical flammability tests. The foams also exhibited improved thermal stabilities and mechanical strengths and good dimensional stabilities. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45748.

Effect of Boron Doping On Graphene Oxide for Ammonia Adsorption

AbstractBoron doped graphene oxide (B‐GO) is a highly effective adsorbent for ammonia due to the high density of strong Lewis acid sites arising from the boron. GO was doped by various amounts of boron described as xB‐GO (x=1.0, 3.0, and 5.0). B‐GO was successfully synthesized and the boron doping was confirmed by X‐ray diffraction, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. The adsorption characteristics of B‐GO were investigated by adsorption isotherm and thermal desorption spectroscopy. The adsorption isotherm shows an increase of ammonia adsorption with increasing concentration of boron such as 12.03 mol kg−1, 16.30 mol kg−1 and 15.58 mol kg−1. It is confirmed that the amount of ammonia adsorbed on the boron sites is limited to a certain amount due to the reduction of Lewis acid sites by B−O bonds. Boron doped into GO significantly enhances the adsorption capacity for ammonia.

Mechanical activation of crystallization of amorphous boron and synthesis of Al3Ti under cold isostatic pressing of B–Al–(LaB6–TiB2) powder

The powder mixture consisting of amorphous boron, crystalline aluminum, and a composite material LaB6–TiB2 is cold-isostatically-pressed under a pressure of up to 0.6 GPa and then heated to 1000°C. It is found out that almost the entire amount of amorphous boron contained in the mixture has been crystallized and the synthesis of Al3Ti has been noted, while the crystallization of amorphous boron usually occurs at a temperature of 1500°C.

Reaction Mechanism and Kinetics of Boron Removal from Metallurgical-Grade Silicon Based on Li2o-SiO2 slags

Slag refining is generally considered as one of the most optimal options for boron removal from metallurgical-grade silicon. Therefore, finding an effective refining agent to eliminate boron from metallurgical-grade silicon is of great importance. In this work, a new Li2O-SiO2 slag system was chosen as a promising agent to remove boron impurity from metallurgical-grade silicon at the conditions of holding time, slag composition and mass ratio of slag to silicon. To lower the production cost and achieve industrial application, slag treatments were carried out under an air atmosphere rather than under protective gas atmosphere. The boron concentration in metallurgical-grade silicon was successfully reduced from 8.6 ppmw to 0.4 ppmw after slag refining for 0.5 h at 1973 K when the mass ratio of the 60wt.% Li2O-40wt.% SiO2 slag to metallurgical-grade silicon was 3. This figure is significantly close to the required boron purity of SOG-Si (below 0.3 ppmw). It was proposed that the addition of CaF2 decreased the activity of silica, which brings about a negative effect on the boron removal capacity of Li2O-SiO2 slags. Moreover, the reaction mechanism and kinetics of boron removal were further investigated. Analysis of the boron concentration in the resulting slag after refining revealed that the primary boron removal approach was that a large amount of boron was oxidized and then volatilized to the atmosphere in the form of gaseous borates. Based on the two-film theory, the total mass transfer coefficient of boron was determined to be 2.3×10-2 μm s-1.

Change in some biochemical and bioactive properties and essential oil composition of coriander seed (Coriandrum sativum L.) varieties from Turkey

Coriander (Coriandrum sativum L.), is a specific species for Mediterranean region and it is cultivated for several purposes such as medicinal, cooking and cosmetic. Coriander seed oil is widely used in the food, health, cosmetics, soft drinks and chocolate industries all around of the world. Coriander essential oil is also utilised by the humans in terms of its medicinal properties traditionally. The present study was aimed to investigate some biochemical and bioactive properties of the coriander samples. Besides, four different varieties from Turkey (Arslan, Gamze, Gürbüz, Erbaa) were compared in the study. The highest crude oil content (COC) was calculated for the Gamze cultivar. The highest amounts of calcium, magnesium, sulphur, copper and boron were determined in the Gamze cultivar while the lowest values were for the Arslan one. The significant variation was observed in mineral contents of seed and seed oil samples. Petroselinic acid was the major fatty acid for all coriander cultivars. The lowest antiradical activity was found in the Erbaa cultivar and the highest amount of total phenolic compounds was for the Arslan cultivar. This study is the first report about biochemical and bioactive properties of the four coriander varieties from Turkey.

Boron’s Importance in Plant Development and Growth: A review

IT’S AN IMPORTANT micronutrient for plant nutrition, the availability of boron is important for growth parameters. The physiological role in plants controlled by boron and its affinity to environment, generally accommodated to excelling appreciating the assignment of boron in plants. Interdict of hydrogen ion deliver due to boron draw up and amends in plant substrate demonstrated boron association in cell wall actions it’s a unique micronutrient depends for common plant growth and optimum yield of crops. Its concentration in soil and plant not only varies with soil, plant, but also its overdose or defect, may affect the plant growth and production. Boron in soils gradually influence by several factors among of its, soil pH, organic matter, nutrient interactions, and plant species. Deficiencies of boron cause a reduction of yield production and quality. However, the toxicity was gradually observed in the presence of Ca application. Function of boron in plant observed in cell division, seed development and sugar transport in plant. Plant needs trace amount of boron for plant growth as compared with primary nutrients. The aim of this review is to understand the physiological duty of boron element in plants.

Thermal properties and formation mechanism of h‐BN nanoneedles synthesized via carbothermic reduction reaction

AbstractHexagonal boron nitride (BN) was synthesized through the carbothermic reduction reaction (CRR) of boric acid using lactose as a carbon source under the nitrogen atmosphere at 1500°C for 3 hours. The boron/carbon (B/C) molar ratio was controlled during the CRR, and the produced samples were investigated by XRD diffraction pattern, FTIR analysis, and Raman spectra. Boron carbide (B4C) was formed in samples that have a higher carbon content, in addition to boron nitride. While boron nitride pure sample was produced from lower carbon content samples. Formation of B4C was found to depend on the B/C molar ratio. The morphology of the produced powder was also investigated by SEM and TEM, which revealed that the samples consist of nanoneedles of BN and hexagonal particles of B4C. The vapor‐solid (VS) reaction mechanism was processed greatly with increasing boron amount, producing boron nitride nanoneedles, which compete with the liquid‐solid (LS) reaction mechanism. The physicochemical properties of the produced samples were studied by DTA, UV, PL, and AC impedance measurements, and revealed that the samples are promising to many proper applications.

The effect of boron on the grain size and texture in additively manufactured β-Ti alloys

One of the critical microstructural attributes affecting the properties of additively manufactured (AM) alloys is the growth of large columnar grains along the build direction. While most of the work in the reported literature is focused on Ti–6Al–4V and other α/β alloys, there are rather limited investigations on grain growth and texture development in AM β-Ti alloys. The addition of trace amounts of boron to these AM β-Ti alloys resulted in significant changes in the microstructure. Depending on the alloy system, a grain refinement of 50–100 times was noted. The change in the grain size has been attributed to a combined effect of constitutional supercooling, caused by boron rejection from the growing β grains, and the growth restriction factor (Q) of the grains caused by the solute elements. The addition of boron also changed the morphology of the grains from being columnar to more equiaxed, a much more pronounced change than observed in traditional α/β alloys such as Ti–6Al–4V. A change in texture of the β grains along the build direction was also noted, wherein the addition of boron randomized the texture from the typically observed strong (001)β oriented grains in AM Ti alloys. Finally, the addition of boron changed the morphology of the α precipitates in the Ti–Mo system from lath-like to more equiaxed, while preserving the Burgers orientation relationship between the α and β phases.

The Effect of Preliminary Mechanical Activation on the Structure and Mechanical Properties of Ni<sub>3</sub>Al+B Material Obtained by SPS

In the present study, a mixture of powders (87.9 at.% Ni, 12 at.% Al, 0.1 at.% B) was used as the initial material to produce sintered Ni3Al + B alloy. Spark Plasma Sintering (SPS) method was used to compact the powder. The powder mixtures were previously prepared in two ways: mixing the initial powders in a mortar (М1) and mechanical activation (М2). The microstructure was observed using optical microscope (OM). The addition of small amount of boron to the initial mixture of nickel and aluminum improves the density of the sintered Ni3Al intermetallic compound (98.8%). The results of density, bending and microhardness tests showed, that the provisional three-minute mechanical activation improves almost all properties of the sintered material. The compact obtained by SPS by M2 contributes to the formation of a homogeneous fine-grained structure of the material. It leads to further increase in flexural bending strength up to 2200 MPa. This value is almost 8 times the strength of the intermetallic Ni3Al stoichiometric composition obtained by SPS.

Record critical current density in bulk MgB2 using carbon-coated amorphous boron with optimum sintering conditions

We report on the synthesis and characterization of a sintered bulk MgB2 material produced at an optimized sintering temperature with a varying content of carbon-encapsulated amorphous boron. A series of MgB2 bulks was prepared with 0%, 1.5%, 2.8%, 7.3%, 12% and 16.5% of carbon-encapsulated boron. In the samples with 12% of carbon-encapsulated boron, Mg and MgB2C2 formation was observed. Tc was around 38.4 K for the pure MgB2 and decreased with increasing carbon content up to 25 K for 16.5 % of carbon-encapsulated boron. The highest Jc values of 470 kA/cm2 and 310 kA/cm2, in the self-field and 1 T, respectively, were achieved at 20 K, in the MgB2 sample with 1.5% of carbon-encapsulated boron. It proved that the optimized sintering conditions together with the appropriate amount of the carbon-coated boron were able to bring critical current performance of bulk MgB2 material up to the level necessary for real technical applications.

High‐pressure behavior of (Cs,K)Al4Be5B11O28 (londonite): A single‐crystal synchrotron diffraction study up to 26 GPa

AbstractThe compressional behavior and the P‐induced deformation mechanisms at the atomic scale of (Cs,K)Al4Be5B11O28 (londonite, a ~7.31 Å and space group P3m) were investigated by in situ single‐crystal synchrotron X‐ray diffraction with a diamond anvil cell up to 26 GPa. No phase transition was observed within the P‐range investigated: this material exhibits isotropic compression (i.e., with cubic symmetry) in response to the applied pressure. Fitting the P–V data with a Birch‐Murnaghan isothermal equation of state, we obtained: V0=390.8(3) Å3, KP0=212(7) GPa (β0=1/KP0=0.0047(1) GPa−1) and K′=4.6(6). A series of structural refinements, based on the high‐pressure intensity data, were performed. The stiffness of londonite (similar to that of carbides) is governed by its close‐packing structure, and in particular by the very low compressibility of B‐ and Be‐tetrahedra and the modest compressibility of the Al‐octahedra. The Cs‐polyhedra are the most compressible units of the structure. The effects of pressure can be accommodated by intrapolyhedral compression or deformation, leading to a modest bulk compression. The high amount of boron in londonite (B2O3 ~50 wt%) makes its synthetic counterpart a potential neutron absorber. In addition, the high content of Cs makes londonite‐type materials as potential hosts for nuclear waste.

The effect of B‐doping on the electrical conductivity of polymer‐derived Si(B)OC ceramics

AbstractIn this work the room temperature electrical conductivity of Si(B)OC glasses made via polymer pyrolysis at 1200°C and 1400°C (maximum temperature) and having different amount of boron was measured. When B content is increased from zero (pure SiOC glass) up to B/Si=0.5 the electrical conductivity increases in 2 orders of magnitude from 4.09±0.64×10−5 up to 2.93±1.91×10−3 with a corresponding decrease in the activation energy from about 1.08 to 0.51 eV. This results shows for the first time that the electrical conductivity of Si‐based polymer‐derived ceramics can be controlled by the amount of the doping element. The structure of the Si(B)OC glasses has been studied with different techniques including FT‐IR, XRD and Raman spectroscopy. The Raman study indicates that B partially substitutes C into the sp2 C planes of the free carbon phase forming trigonal BC3 units. Accordingly, the evolution of the electrical properties with the B content has been correlated with the corresponding structural evolution and a hypothesis is presented to rationalize the role of boron on the electrical conductivity of SiOBC glasses.

Ionic conductivity in BC3 type boron carbon nanolayers

Studies of ionic conductivity and structuresf in which it can be achieved are of great importance for the development of modern batteries. The use of new materials will allow avoiding such typical disadvantages of batteries as short service life, low capacity and leaks. In this article we present the results of our study of the ionic conductivity in boron carbon nanolayers. We have simulated three types of boron carbon nanolayers containing different amounts of boron. The studies have been carried out using the MNDO method within the framework of the molecular cluster model and the DFT method with the B3LYP functional and the 6–31G basis. To study the ion conduction process we have simulated vacancy formation for each type of the nanolayers and studied the energy and electronic characteristics of these processes. We show that 25% boron substitution is the most energetically favorable for vacancy formation. We have also simulated vacancy migration and determined the thermal conductivity as a function of temperature.