Selective Synthesis of Boron Nitride Nanotubes

2011 ◽  
Vol 694 ◽  
pp. 408-412
Author(s):  
Lai Ping Zhang ◽  
Ji Lin Wang ◽  
Guo Wei Zhao ◽  
Zhan Hui Zhang ◽  
Fang Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Boron Nitride ◽  
Boron Nitride Nanotubes ◽  
Selective Synthesis ◽  
Controllable Synthesis ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Transmission Electron ◽  
Bn Nanotubes ◽  
Shs Method

Four types of boron nitride (BN) nanotubes are selectively synthesized by annealing porous precursor in flowing NH3 and NH3/H2 atmosphere at temperature ranging from 1000 to 1200°C in a vertical furnace. The as-synthesized BN nanotubes, including cylinder, wave, bamboo and bubble-chain, are characterized by scanning and transmission electron microscopy. Selectivity of BN nanotubes is estimated as approximately 80 to 95%. The porous precursor B31Fe17(MgO)27 prepared by self-propagation high-temperature synthesis (SHS) method plays a key role in controllable synthesis of the as-grown BN nanotubes. The chemical reaction and annealing mechanism are also discussed.

scholarly journals Synthesis of Boron Nitride Nanotubes by Self-Propagation High-Temperature Synthesis and Annealing Method

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Jilin Wang ◽  
Yunle Gu ◽  
Laiping Zhang ◽  
Guowei Zhao ◽  
Zhanhui Zhang
Keyword(s):  
High Temperature ◽  
Boron Nitride ◽  
Average Diameter ◽  
Boron Nitride Nanotubes ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Effects Of Temperature ◽  
Temperature Time ◽  
Annealing Method ◽  
Bn Nanotubes

High-quality boron nitride nanotubes were synthesized by annealing porous precursor in flowing NH3gas at 1150°C. The porous precursor B18Ca2(MgO)9was produced by self-propagation high-temperature synthesis (SHS) method using Mg, B2O3, and CaB6as the starting materials, which played an important role in synthesis of BN nanotubes in large quantities. Samples were characterized by SEM, TEM, EDX, HRTEM, X-ray powder diffraction (XRD), Raman, and Fourier transform infrared (FTIR) spectroscopy. The as-synthesized BN nanotubes have an average diameter of about 150 nm with a wall/diameter ratio of 2/3. Mean length of the BN nanotubes was more than 10 μm. The effects of temperature, time, and the possible mechanism of the growth of the BN nanotubes were also discussed.

Boron Nitride Nanotubes: Nanoparticles Functionalization and Junction Fabrication

2007 ◽  
Vol 7 (2) ◽  
pp. 530-534 ◽  
Author(s):  
Chunyi Zhi ◽  
Yoshio Bando ◽  
Guozhen Shen ◽  
Chengchun Tang ◽  
Dmitri Golberg
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Boron Nitride ◽  
Boron Nitride Nanotubes ◽  
X Ray Diffraction ◽  
Carbon Nanostructure ◽  
Wet Chemistry ◽  
X Ray ◽  
Transmission Electron ◽  
First Time

Adopting a wet chemistry method, Au and Fe3O4 nanoparticles were functionalized on boron nitride nanotubes (BNNTs) successfully for the first time. X-ray diffraction pattern and transmission electron microscopy were used to characterize the resultant products. Subsequently, a method was proposed to fabricate heterojunction structures based on the particle-functionalized BNNTs. As a demonstration, BNNT-carbon nanostructure, BNNT-ZnO and BNNT-Ga2O3 junctions were successfully fabricated using the functionalized particles as catalysts.

Combustion for the Synthesis of β-SiC and Diamond/SiC Composite

1993 ◽  
Vol 327 ◽  
Author(s):  
Rohini Raghunathan ◽  
Rina Chowdhury ◽  
Jagdish Narayan
Keyword(s):  
Electron Microscopy ◽  
Exothermic Reaction ◽  
Diamond Films ◽  
Temperature Synthesis ◽  
X Ray ◽  
High Temperature Synthesis ◽  
Transmission Electron ◽  
Set Up ◽  
Spectroscopy Studies

AbstractCubic β-SiC was processed under conditions of self-propagating high-temperature synthesis, based on the exothermic reaction between elemental Si and C powders. The set up for the synthesis of SiC using a mixture of Si and C is described. X-Ray and Raman spectroscopy studies were performed to characterize the quality of the β-SiC produced using the new set up. Scanning Electron Microscopy and Transmission Electron Microscopy studies were also carried out to study the mechanism of the formation of β-SiC from the elemental powders. The density of the compact and grain size of the graphite was found to be critical in the formation of the SiC. Diamond seeds were also implanted on the SiC pellet while compaction and this implanted diamond provided the necessary seed for the growth of a thick diamond film. The adhesion of the film is good because of its growth from the implanted diamond. Diamond films were grown on SiC using HFCVD. The quality and the adhesion of the diamond films on SiC were studied using SEM.

Investigation on B, Cr Doped Ni3Al Alloy Prepared by Self-Propagation High-Temperature Synthesis and Hot Extrusion

2013 ◽  
Vol 747-748 ◽  
pp. 124-131 ◽  
Author(s):  
Li Yuan Sheng ◽  
Jian Ting Guo ◽  
Chao Yuan ◽  
F. Yang ◽  
G.S. Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Temperature ◽  
Hot Extrusion ◽  
The Self ◽  
Al Alloy ◽  
Temperature Synthesis ◽  
X Ray ◽  
High Temperature Synthesis ◽  
Transmission Electron

The Ni3Al and Ni3Al-B-Cr alloys were fabricated by the self-propagation high-temperature synthesis with hot extrusion method. Their microstructure and mechanical properties were studied by using combination of X-ray diffraction, optical microscopy, transmission electron microscopy and compression test. Analysis of X-ray spectra exhibited that the elemental powders had been transformed to the Ni3Al phase after the self-propagation high-temperature synthesis processing. Microstructure examination showed that the alloy without extrusion consisted of coarse and fine grains, but the subsequent hot extrusion procedure homogenized the grain size and densified the alloy obviously. Transmission electron microscopy observations on the Ni3Al alloy revealed that Ni3Al, γ-Ni and Al2O3 particles were the main phases. When the boron and chromium were added, besides the β-NiAl phase, α-Cr phase and some Cr7Ni3 particles with stacking faults inside were observed. In addition, a lot of substructure and high-density dislocation arrays were observed in the extruded part, which indicated that the subsequent extrusion had led to great deformation and partly recrystallizing in the alloy. Moreover, the subsequent extrusion procedure redistributed the Al2O3 particles and eliminated the γ-Ni. These changes were helpful to refine the microstructure and weaken the misorientation. The mechanical test showed that the self-propagation high-temperature synthesis with hot extrusion improved the mechanical properties of the Ni3Al alloy significantly. The addition of B and Cr in Ni3Al alloy increased the mechanical properties further, but the compressive strength of the alloy was still lower than that synthesized by combustion. Finally, the self-propagation high-temperature synthesis with hot extrusion was a good method to prepare Ni3Al alloy from powder.

Determination of Non-Stoichiometry of Tubular Titanium Carbide Formed by Self-Propagating High Temperature Synthesis

2007 ◽  
Vol 534-536 ◽  
pp. 1301-1304
Author(s):  
Y. Choi ◽  
Nam Ihn Cho
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Temperature ◽  
Titanium Carbide ◽  
Combustion Temperature ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Scanning Electron ◽  
Shs Method

Titinium carbide (TiCx) was produced by self-propagating high temperature synthesis (SHS) method. The morphology and non-stoichiometric number of the SHS product were observed by scanning electron microscopy and neutron diffractometry, respectively. Tubular titanium carbide with hole inside was formed with different non-stoichiometric number (x), which value increased with combustion temperature.

Boron Nitride Nanotube, Nanocable and Nanocone

2001 ◽  
Vol 706 ◽  
Author(s):  
Dmitri Golberg ◽  
Yoshio Bando ◽  
Laure Bourgeois ◽  
Renzhi Ma ◽  
Kazuhiko Ogawa ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Nitrogen Atmosphere ◽  
Boron Nitride Nanotubes ◽  
X Ray ◽  
Atomic Structures ◽  
Transmission Electron ◽  
Electron Energy Loss Spectrometer ◽  
Line Defects ◽  
Electron Energy Loss ◽  
Bn Nanotubes

AbstractBoron nitride nanotubes, nanocones and nanocables were prepared and their atomic structures were identified by using a 300 kV field emission transmission electron microscope equipped with an electron energy loss spectrometer and energy dispersion X-ray detector. Multiwalled BN nanotubes and nanocones were synthesized by reacting C nanotube templates and boron oxide under nitrogen atmosphere at 1723-2023 K. Additions of metal oxide promoters, e.g. MoO3, CuO, and PbO, significantly improved BN-rich nanotube yield at the expense of B-C-N nanotubes. It was shown that BN nanotubes had preferential “zigzag” chirality and exhibited either hexagonal or rhombohedral stacking between shells. An efficient synthetic route for bulk quantities of BN tube production was also developed, where a B-N-O precursor was used during a CVD process. Nanocones of BN were mostly found to have 240° disclinations which ensure the presence of B-N bonds only. One case was observed of a cone constituted of 300° disclination implying that structures may contain line defects of non B-N bonds. The first synthesis of insulating BN nanocables was carried out, where BN nanotubes were entirely filled with Invar Fe-Ni nanorods. The filled nanotube diameters ranged between 30 to 300 nm, whereas the length of filling reached several microns.

scholarly journals Intrinsic and Defect-Related Elastic Moduli of Boron Nitride Nanotubes As Revealed by in Situ Transmission Electron Microscopy

Nano Letters ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 4974-4980 ◽  
Author(s):  
Xin Zhou ◽  
Dai-Ming Tang ◽  
Masanori Mitome ◽  
Yoshio Bando ◽  
Takayoshi Sasaki ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Boron Nitride ◽  
Elastic Moduli ◽  
Boron Nitride Nanotubes ◽  
Transmission Electron

High-Yield Synthesis of Bamboo-Like BN Nanotubes Using Self-Propagation High Temperature Synthesized Porous Precursor

2011 ◽  
Vol 694 ◽  
pp. 59-63
Author(s):  
Lai Ping Zhang ◽  
Ji Lin Wang ◽  
Yun Le Gu ◽  
Guo Wei Zhao ◽  
Qiong Li Qian ◽  
...  
Keyword(s):  
High Temperature ◽  
Boron Nitride ◽  
Synthesis Method ◽  
Chemical Vapor ◽  
Boron Nitride Nanotubes ◽  
High Yield ◽  
Synthesis Process ◽  
Chemical Vapor Deposition Method ◽  
Temperature Synthesis ◽  
High Temperature Synthesis

High-yield and high-purity bamboo-like boron nitride nanotubes were synthesized via an effective chemical vapor deposition method by annealing porous precursor under ammonia atmosphere at 1150 °C. The porous precursor, prepared by self-propagation high temperature synthesis method, was the key to bulk synthesis process. The as-synthesized boron nitride nanotubes were characterized by SEM, TEM, HRTEM, XRD, Raman and FTIR spectroscopy. These nanotubes had a bamboo-like structure with uniform diameters about 90 nm and length of more than 10 μm. The associated growth model is proposed in this paper.

Effect of NaCl on Synthesis of Si-SiC Nanocomposites by Self Propagating High Temperature Synthesis

2013 ◽  
Vol 664 ◽  
pp. 449-453 ◽  
Author(s):  
Sutham Niyomwas
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
Nano Composite ◽  
Argon Gas ◽  
X Ray ◽  
High Temperature Synthesis ◽  
Transmission Electron ◽  
Scanning Electron

The Si-SiC nanocomposites have been synthesized by self-propagating high temperature synthesis (SHS) from natural precursors. The effects of difference amount of added NaCl from 0 to 0.75 moles to the reactants on the Si-SiC conversion and particle size were investigated. The reaction were carried out in a SHS reactor under static argon gas at the pressure of 0.5 MPa. The nanocomposite results have been characterized by scanning electron microscope, Transmission Electron Microscopy and X-ray diffraction. The results showed that the production of nano-composite materials using SHS process is feasible and agree well with the thermodynamics calculations.

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