Modeling of the Formation of Boron Carbide Particles in an Aerosol Flow Reactor

1992 ◽  
Vol 242 ◽  
Author(s):  
Yun Xiong ◽  
Sotiris E. Pratsinis ◽  
W. Weimer
Keyword(s):  
Boron Carbide ◽  
Surface Area ◽  
Boron Oxide ◽  
Flow Reactor ◽  
Distribution Model ◽  
Two Dimensional ◽  
Heating Rates ◽  
Aerosol Flow ◽  
Average Size ◽  
Carbide Particles

ABSTRACTThe formation of submicron crystals of boron carbide (B4C) by rapid carbothermal reduction of intimately mixed carbon-boron oxide precursor powders in an aerosol flow reactor at temperatures above the boiling point of boron oxide is investigated. The employed high heating rates (105 K/s) of the process force release of gaseous boron oxide and suboxides and rupture of the precursor particles resulting in formation of boron carbide molecular clusters that grow to macroscopic particles by coagulation. Consequently, the formation and growth of B4C particles is described by simultaneous interparticle collision and coalescence using a two-dimensional distribution model that traces the evolution of both size and shape characteristics of the particles through their volume and surface area. Here, in addition to the coagulation term, the governing population balance equation includes a coalescence contribution based on B4C sintering law. The predicted evolution of the two-dimensional particle size distribution leads to a direct characterization of morphology as well as the average size and polydispersity of the powders. Furthermore, model predictions of the volume and surface area of boron carbide particles can be directly compared with experimental data of B4C specific surface area and grain size.

Modeling the formation of boron carbide particles in an aerosol flow reactor

AIChE Journal ◽  
1992 ◽  
Vol 38 (11) ◽  
pp. 1685-1692 ◽  
Author(s):  
Yun Xiong ◽  
Sotiris E. Pratsinis ◽  
Alan W. Weimer
Keyword(s):  
Boron Carbide ◽  
Flow Reactor ◽  
Aerosol Flow ◽  
Carbide Particles

scholarly journals Получение карбида бора в низковольтной электрической дуге постоянного тока, инициированной в открытом воздушном пространстве

2018 ◽  
Vol 44 (14) ◽  
pp. 26 ◽  
Author(s):  
А.Я. Пак ◽  
Г.Я. Мамонтов
Keyword(s):  
Boron Carbide ◽  
Arc Discharge ◽  
Electron Microscopic Examination ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Vacuum Equipment ◽  
X Ray ◽  
Gas Atmosphere ◽  
Average Size ◽  
Carbide Particles

AbstractWe describe a method of obtaining ultrafine boron carbide (B_13C_2) powder using the effect of a dc electric arc on a mixture of initial reactants containing carbon and boron. A peculiarity of the proposed method is that it can be implemented using arc discharge operating in open air without any vacuum equipment and protective inert gas atmosphere. X-ray diffraction data showed that the synthesized product in the general case contained three crystalline phases: boron carbide (B_13C_2), graphite (C), and boron oxide (B_2O_3). Electron-microscopic examination showed that the average size of boron carbide particles ranged from ~50 nm to ~2 μm.

Preparation of Boron Carbide Nanoparticles by Carbothermal Reduction Method

2004 ◽  
Vol 848 ◽  
Author(s):  
Baohe Chang ◽  
Bonnie Gersten ◽  
Jane W. Adams ◽  
Steve Szewczyk
Keyword(s):  
Boron Carbide ◽  
Reduction Method ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Boron Powder ◽  
X Ray ◽  
Transmission Electron ◽  
Crystalline Boron ◽  
Average Size ◽  
Carbide Particles

ABSTRACTA carbothermal reaction process was employed to synthesize nano-sized boron carbide particles. The reactions were carried out by heating a mixture of boric oxide powder and amorphous carbon reactant under a flow of argon atmosphere in a conventional high temperature tube furnace at 1350–1700 °C for 1–4 h. In order to obtain stoichiometric powder product, additional pure boron powder was added to the reaction mixture to compensate for the boron loss in the form of B2O2/B2O3vapor during the reaction. The effect of the structure and morphology of the precursor materials on that of the products was also investigated. X-ray diffraction (XRD) studies indicated that the powdered product prepared under optimized reaction conditions was crystalline boron carbide. Transmission electron microscopy (TEM) observations showed that the product nanoparticles ranged from 50 nm to 250 nm with the average size between 100 nm and 150 nm depending on the reaction conditions. Some boron carbide particles were as small as 50 nm. Energy dispersive spectroscopy (EDS) was also used to determine the stoichiometry of the boron carbide nanoparticle products.

Electroless Copper Coating on Boron Carbide Particles by Using Copper Activation Method

2014 ◽  
Vol 576 ◽  
pp. 127-131
Author(s):  
Wei Wang ◽  
Qiu Lin Li ◽  
Wei Liu ◽  
You Wei Yao ◽  
Xue Jun Li
Keyword(s):  
Boron Carbide ◽  
Activation Method ◽  
Complexing Agent ◽  
X Ray Diffraction ◽  
Electroless Coating ◽  
X Ray ◽  
Structure And Morphology ◽  
Coating Layers ◽  
Average Size ◽  
Carbide Particles

The present work is focused on electroless coating of copper nanolayer onto boron carbide (B4C) particle surfaces by using copper activation method. The B4C particles used are approximately 18.25μm in average size. B4C particle surfaces were washed by acetone and activated through copper activation method. In the electroless coating bath, copper sulfate, EDTA-2Na and seignette salt, hydrazine hydrate were used as the copper catalytic centers source, complexing agent and reducing agent respectively. The structure and morphology of the coating layers were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD and SEM observations show that B4C particle surfaces were successfully coated by a homogeneous and continuous copper layer.

Ti3C2-MXene/Bismuth Ferrite Nanohybrids for Efficient Degradation of Organic Dye and Colorless Pollutant

2019 ◽  
Author(s):  
Ayesha Tariq ◽  
M. Abdullah Iqbal ◽  
S. Irfan Ali ◽  
Muhammad Z. Iqbal ◽  
Deji Akinwande ◽  
...  
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
Bismuth Ferrite ◽  
Organic Dye ◽  
Two Dimensional ◽  
Electron Hole ◽  
Photocatalytic Application ◽  
Electron Hole Pair ◽  
Pair Generation ◽  
Photocatalytic Applications

<p>Nanohybrids, made up of Bismuth ferrites/Carbon allotropes, are extensively used in photocatalytic applications nowadays. Our work proposes a nanohybrid system composed of Bismuth ferrite nanoparticles with two-dimensional (2D) MXene sheets namely, the BiFeO<sub>3</sub> (BFO)/Ti<sub>3</sub>C<sub>2</sub> (MXene) nanohybrid for enhanced photocatalytic activity. We have fabricated the BFO/MXene nanohybrid using simple and low cost double solvent solvothermal method. The SEM and TEM images show that the BFO nanoparticles were attached onto the MXene surface and in the inter-layers of two-dimensional (2D) MXene sheets. The photocatalytic application is tested for the visible light irradiation which showed the highest efficiency among all pure-BFO based photocatalysts, i.e. 100% degradation in 42 min for organic dye (Congo Red) and colorless aqueous pollutant (acetophenone) in 150 min, respectively. The present BFO-based hybrid system exhibited the large surface area of 147 m<sup>2</sup>g<sup>-1</sup>measured via Brunauer-Emmett-Teller (BET) sorption-desorption technique, and is found to be largest among BFO and its derivatives. Also, the photoluminescence (PL) spectra indicate large electron-hole pair generation. Fast and efficient degradation of organic molecules is supported by both factors; larger surface area and lower electron-hole recombination rate. The BFO/MXene nanohybrid presented here is a highly efficient photocatalyst compared to other nanostructures based on pure BiFeO<sub>3</sub> which makes it a promising candidate for many future applications.</p>

Functional Two-Dimensional Black Phosphorus Nanostructures towards Next-Generation Devices

2021 ◽  
Author(s):  
Mengke Wang ◽  
Jun Zhu ◽  
You Zi ◽  
Zheng-Guang Wu ◽  
Haiguo Hu ◽  
...  
Keyword(s):  
Surface Area ◽  
Biomedical Applications ◽  
Black Phosphorus ◽  
Large Surface Area ◽  
Two Dimensional ◽  
Next Generation

In recent years, two-dimensional (2D) black phosphorus (BP) has been widely applied in many fields, such as (opto)electronics, transistors, catalysis and biomedical applications due to its large surface area, tunable...

Mechanical characterization of LM25 alloy matrix composite reinforced with boron carbide

2021 ◽  
pp. 002199832110055
Author(s):  
Zeeshan Ahmad ◽  
Sabah Khan
Keyword(s):  
Tensile Strength ◽  
Boron Carbide ◽  
Mechanical Characterization ◽  
Stir Casting ◽  
Surface Mapping ◽  
Alloy Matrix ◽  
Casting Technique ◽  
The Matrix ◽  
Carbide Particles

Alumnium alloy LM 25 based composites reinforced with boron carbide at different weight fractions of 4%, 8%, and 12% were fabricated by stir casting technique. The microstructures and morphology of the fabricated composites were studied by scanning electron microscopy and energy dispersive spectroscopy. Elemental mapping of all fabricated composites were done to demonstrate the elements present in the matrix and fabricated composites. The results of microstructural analyses reveal homogenous dispersion of reinforcement particles in the matrix with some little amount of clustering found in composites reinforced with 12% wt. of boron carbide. The mechanical characterization is done for both alloy LM 25 and all fabricated composites based on hardness and tensile strength. The hardness increased from 13.6% to 21.31% and tensile strength 6.4% to 22.8% as reinforcement percentage of boron carbide particles increased from 0% to 12% wt. A fractured surface mapping was also done for all composites.

Research on metallic chalcogen-functionalized monolayer-puckered V2CX2 (X = S, Se, and Te) as promising Li-ion battery anode materials

2021 ◽  
Author(s):  
Chunmei Tang ◽  
Xiaoxu Wang ◽  
Shengli Zhang
Keyword(s):  
Surface Area ◽  
Anode Materials ◽  
Large Surface Area ◽  
Two Dimensional ◽  
Li Ion Batteries ◽  
Li Ion Battery ◽  
Li Ion ◽  
Battery Anode

Two-dimensional MXene nanomaterials are promising anode materials for Li-ion batteries (LIBs) due to their excellent conductivity, large surface area, and high Li capability.

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