Crystalline Boron Carbide Encapsulated Into Carbon Nanoclusters from Arc-Discharge Soot

1994 ◽  
Vol 359 ◽  
Author(s):  
Supapan Seraphin ◽  
Dan Zhou ◽  
Jun Jiao
Keyword(s):  
Boron Carbide ◽  
Arc Discharge ◽  
Carbon Clusters ◽  
Composite Anode ◽  
Boron Compounds ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Crystalline Boron ◽  
Carbon Nanoclusters ◽  
Electron Energy Loss

ABSTRACTUsing a boron-containing composite anode in an arc discharge, we found in the soot on the reactor walls graphitic multiwalled carbon clusters that contained boron carbide crystals, as identified by high resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), and electron diffraction. The encapsulants are compounds of the lightest element that has yet been encapsulated, and the first of the non-metallic. The multiwalled graphitic cages partially encapsulating the boron compounds have rarely been observed in the soot of arc-discharge material produced from anodes not containing boron. We explain this exception by the known tendency of boron to catalyze graphitization.

Effect of growth conditions on B-doped carbon nanotubes

2006 ◽  
Vol 21 (12) ◽  
pp. 3058-3064 ◽  
Author(s):  
Sara M.C. Vieira ◽  
Odile Stéphan ◽  
David L. Carroll
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Arc Discharge ◽  
Amorphous Material ◽  
Graphite Powder ◽  
Growth Conditions ◽  
Multiwalled Carbon ◽  
Boron Doped ◽  
Transmission Electron ◽  
Electron Energy Loss

The modified arc-discharge technique was used for the growth of boron-doped multiwalled carbon nanotubes. A variety of weight percentages of boron and sulfur were mixed (0.5–15 wt%) with graphite powder and packed in the consumable anode. Transmission electron microscopy, Raman spectroscopy, thermogravimetric analysis (TGA), and electron energy loss spectroscopy (EELS) were used to characterize the samples. EELS indicated a small percentage of boron present (<1 at.%) in the nanotubes. Sulfur was used primarily to enhance boron incorporation; however, Raman and TGA measurements indicated fewer defects and/or amorphous material present when sulfur was added.

The Possibility of Boron Carbide Coating Formation by Using a Coaxial Magnetoplasma Accelerator

2015 ◽  
Vol 1097 ◽  
pp. 45-49
Author(s):  
Alexander Sivkov ◽  
Ilyas Rakhmatullin ◽  
Anastasiya Makarova
Keyword(s):  
Electron Microscopy ◽  
Boron Carbide ◽  
Arc Discharge ◽  
Copper Substrate ◽  
Carbide Coating ◽  
Carbide Coatings ◽  
Transmission Electron ◽  
Crystalline Boron ◽  
Coating Formation ◽  
Coaxial Magnetoplasma Accelerator

A coaxial magnetoplasma accelerator can generate a dense and high velocity plasma jet by applying a pulsed high-current arc-discharge. The results of the experiment investigations of plasmadynamic synthesis in the B-C system have been shown while hyper speed jet boron carbide electric–discharged plasma steams onto copper substrate. The boron carbide coatings were formed on the copper substrate without a binder material. The formation of the crystalline boron carbide coating on the copper substrate was analysed through X-ray diffraction, transmission electron microscopy and scanning electron microscopy.

Study of the Effect of Anode/Cathode Geometry on the Yield Rate and Quality of the MWCNTs Synthesized by Submerged Arc Discharging

2013 ◽  
Author(s):  
Osama M. Awadallah ◽  
Ragaie M. Rashad ◽  
Abdalla S. Wifi
Keyword(s):  
Arc Discharge ◽  
Multiwalled Carbon ◽  
Yield Rate ◽  
Transmission Electron ◽  
Water As Solvent ◽  
Quantitative Manner ◽  
A356 Aluminum ◽  
Submerged Arc ◽  
Selection Of

The main objective of the present paper is to clarify the effect of anode/cathode geometry combinations on the yield rate and quality of the Multiwalled Carbon Nanotubes (MWCNTs) produced by submerged arc discharge technique. The effects of current intensity and the discharging medium (solvent) are also investigated. The morphology and crystalline perfection of the produced MWCNTs are confirmed by transmission electron microscopy (TEM) and Electron diffraction. Thermogravimetric analysis (TGA) is conducted to check the quality of the MWCNTs in a quantitative manner. The flat ended anode/cathode combination of diameters 4 and 12 mm respectively exhibited the highest yield at 70 A using deionized water as solvent. Through careful selection of the process parameters, the yield rate of MWCNTs obtained is found to be higher than most of the reported values in literature. However, the best quality of MWCNTs with purity as high as 95%, average thermal stability of 745°C as well as good batch homogeneity, is obtained with KCl solution and tapered male/female anode combination. The best quality MWCNTs is used successfully as reinforcement for A356 aluminum silicon composite.

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.

scholarly journals Effects of Increasing Electrodes on CNTs Yield Synthesized by Using Arc-Discharge Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Samy Yousef ◽  
A. Khattab ◽  
T. A. Osman ◽  
M. Zaki
Keyword(s):  
Electron Microscope ◽  
Arc Discharge ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Pure Graphite ◽  
Transmission Electron ◽  
Multiple Electrodes ◽  
Fully Automatic ◽  
Single Plasma

A new design of fully automatic system was built up to produce multiwalled carbon nanotube (MWCNT) using arc discharge technique in deionized water and extra pure graphite multiple electrodes (99.9% pure). The goal of the experimental research is to determine the yield of CNT in two different cases: (a) single plasma electrodes and (b) multiplasma electrodes, particularly 10 electrodes. The experiments were performed at constant parameters (75 A, 238 V). The obtained CNT was examined by scanning electron microscope (SEM), transmission electron microscope (HRTEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results showed that the produced CNT is of type MWCNT, with a diameter of 5 nm, when using multiplasma electrodes and 13 nm when using single plasma electrodes. The yield of MWCNT was found to be 320% higher in case of comparing multielectrodes to that of single plasma electrodes. Under the experimental test conditions, a yield of 0.6 g/hr soot containing 40% by mass nanotube was obtained in case of single plasma electrodes and above 60% in case of multiplasma electrodes.

scholarly journals Enhanced Photocatalytic Degradation of Methylene Blue Using ZnFe2O4/MWCNT Composite Synthesized by Hydrothermal Method

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Sonal Singhal ◽  
Rimi Sharma ◽  
Charanjit Singh ◽  
S. Bansal
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Hydrothermal Method ◽  
Arc Discharge ◽  
Outer Diameter ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
One Step

Multiwalled carbon nanotubes (MWCNTs) were synthesized using arc discharge method at a magnetic field of 430 G and purified using HNO3/H2O2. Transmission electron micrographs revealed that MWCNTs had inner and outer diameter of ~2 nm and ~4 nm, respectively. Raman spectroscopy confirmed formation of MWCNTs showing G-band at 1577 cm−1. ZnFe2O4 and ZnFe2O4/MWCNT were produced using one step hydrothermal method. Powder X-ray diffraction (XRD) confirmed the formation of cubic spinel ZnFe2O4 as well as incorporation of MWCNT into ZnFe2O4. Visible light photocatalytic degradation of methylene blue (MB) was studied using pure ZnFe2O4 and ZnFe2O4/MWCNT. The results showed that ZnFe2O4/MWCNT composite had higher photocatalytic activity as compared to pure ZnFe2O4. After irradiation for 5 hours in the visible light, MB was almost 84% degraded in the presence of ZnFe2O4 photocatalyst, while 99% degradation was observed in case of ZnFe2O4/MWCNT composite. This enhancement in the photocatalytic activity of composite may be attributed to the inhibition of recombination of photogenerated charge carriers.

Formation of boron carbonitride nanotubes from in situ grown carbon nanotubes for space applications

2004 ◽  
Vol 851 ◽  
Author(s):  
F. Piazza ◽  
J. E. Nocua ◽  
A. Hidalgo ◽  
J. De Jesús ◽  
R. Velázquez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Kinetic ◽  
Arc Discharge ◽  
High Yield ◽  
Boron Carbonitride ◽  
Space Applications ◽  
Transmission Electron ◽  
Electron Energy Loss

ABSTRACTBoron carbonitride nanotubes (BCNNTs) were grown with high yield by arc discharge without catalyst particles or pre-grown template nanostructures. Two types of nanotubes (NTs) were formed: thin NTs with diameters of 10–15 nm and thick NTs with diameters of 25–50 nm, all multiwall. Transmission electron microscopy, electron energy loss spectroscopy, and Raman spectroscopy analyses indicate that the thin NTs are carbon NTs (CNTs) while the thick NTs are BCNNTs wrapped around CNTs. The growth kinetic appears to be faster for CNTs than for BCNNTs. Through the concerted substitution of B and N for C in the in situ grown CNTs, template growth of BCNNTs follows the CNTs growth without causing topological changes.

Facile Synthesis of Pure Boron Nanotubes and Nanofibers

2011 ◽  
Vol 1307 ◽  
Author(s):  
Jinwen Liu ◽  
Zafar Iqbal
Keyword(s):  
Chemical Vapor ◽  
Catalyst Precursor ◽  
Magnesium Boride ◽  
Transmission Electron ◽  
Structure Morphology ◽  
High Resolution Tem ◽  
Crystalline Boron ◽  
Boron Nanostructures ◽  
20 Nm ◽  
Electron Energy Loss

ABSTRACTA facile and scalable chemical vapor deposition (CVD) process in flowing argon using a solid instead of a reactive gaseous boron precursor has been carried out to synthesize crystalline boron nanostructures comprising of relatively straight boron nanotubes (BNTs) and nanofibers (BNFs). The synthesis involves the use of solid magnesium boride as the boron and magnesium catalyst precursor, nickel boride as co-catalyst, and MCM-41 zeolite as the growth template. The BNTs and BNFs produced have a narrow distribution of diameters between about 10 nm to 20 nm and lengths from about 500 nm to above 1 μm. Scanning and transmission electron microscope (SEM and TEM) imaging together with electron energy loss spectroscopy (EELS) and energy dispersive spectroscopy (EDS) have been conducted to characterize the structure, morphology and growth mechanism of these novel nanostructures. High resolution TEM imaging has been used to identify BNTs and BNFs in the nanostructures synthesized.

NANO-CRYSTALS OF c-DIAMOND, n-DIAMOND AND i-CARBON GROWN IN CARBON-ION IMPLANTED FUSED QUARTZ

2001 ◽  
Vol 15 (23) ◽  
pp. 3107-3123 ◽  
Author(s):  
J. L. PENG ◽  
J. O. ORWA ◽  
B. JIANG ◽  
S. PRAWER ◽  
L. A. BURSILL
Keyword(s):  
Carbon Clusters ◽  
Quartz Surface ◽  
Carbon Ions ◽  
Selected Area Electron Diffraction ◽  
Nano Crystalline ◽  
Transmission Electron ◽  
Fused Quartz ◽  
Waveguide Type ◽  
Average Size ◽  
Electron Energy Loss

Combined high-resolution transmission electron microscopy, selected area electron diffraction and parallel electron energy loss spectroscopy are used to characterise carbon nano-phases found embedded in fused quartz. These appear after implantation of 1 MeV carbon ions, followed by annealing in argon, oxygen and forming gas for 1 hour at 1100°C. For Ar, virtually all of the carbon diffuses out of the substrate with no observable carbon clusters for all doses studied. After annealing in oxygen, a crystalline CO x phase is identified at the end of range, following a dose of 5×1017 C/cm 2. Three nano-crystalline carbon phases, including diamond, appear after annealing in forming gas: these form a layer 170 nm beneath the fused quartz surface for all ion doses. The average size of these clusters and the corresponding phases depend on the ion dose; the smallest size of 5–7 nm diameter crystallise as fcc [Formula: see text] diamond following a dose of 0.5× 1017 C/cm 2, whereas clusters of 8–13 nm diameter, for a higher dose of 2× 1017 C/cm 2, have a [Formula: see text] modified phase of diamond known as n-diamond. The largest clusters, diameter 15–40 nm, for a dose of 5× 1017 C/cm 2, have the cubic P2 13 (or P4 232) structure known as i-carbon. These buried layered diamond and diamond-related materials may have applications for field emission and optical waveguide type devices.

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