10043-11-5Relevant articles and documents
A room-temperature approach to boron nitride hollow spheres
Chen, Luyang,Gu, Yunle,Shi, Liang,Yang, Zeheng,Ma, Jianhua,Qian, Yitai
, p. 537 - 540 (2004)
Boron nitride hollow spheres were synthesized by the reaction of BBr 3 and NaNH2 at room temperature; X-ray powder diffraction pattern could be indexed as hexagonal BN with the lattice constants of a=2.482 and c=6.701?; high-resolution transmission electron microscopy image showed the hollow spheres consisted of BN nanoparticles, with diameter between 80 and 300 nm; a possible formation mechanism of BN hollow spheres was discussed.
A novel precursor for synthesis of pure boron nitride nanotubes
Tang, Chengchun,Bando, Yoshio,Sato, Tadao,Kurashima, Keiji
, p. 1290 - 1291 (2002)
A novel precursor, a mixture of B2O2 and Mg which is generated in situ by reacting B and MgO at 1300°C, can be used to effectively synthesize bulk amounts of pure BN nanotubes with Mg evaporated from the final product; transmission electron microscope observation for the synthesized BN nanotubes indicates that defects present strongly depend on the tube diameter.
One pot synthesis of ultrathin boron nitride nanosheet-supported nanoscale zerovalent iron for rapid debromination of polybrominated diphenyl ethers
Wang, Liancheng,Ni, Shou-Qing,Guo, Chunli,Qian, Yitai
, p. 6379 - 6387 (2013)
To minimize the aggregation and size effects of nanoscale zerovalent iron (nZVI), nZVI/boron nitride nanosheets (BNNSs) composites were fabricated via a one pot autoclave route on a gram-scale. BNNSs (1-6 nm) supported nZVI (4-40 nm) was prepared by heating NaBH4, FeCl3 and NaN3 at 400 °C. The BNNSs matrixes benefit the retention of the activity for nZVI. The high specific surface area (182 m2 g -1) and density of structural defects allows enrichment of the pollutants, leading to a relatively high conversion by the nearby supported nZVI. Meanwhile, the gram-scale bifunctional nZVI/BNNSs have both reductive and magnetic properties, which make them highly reactive towards the test polybromodiphenyl ethers (PBDEs) and also easy to separate. The reaction rate of nZVI/BNNSs is almost twice that of the nZVI made in our lab. This study indicates that gram-scale nZVI/BNNSs are highly efficient and effective materials that can be utilized to treat PBDEs-contaminated sites, followed by the sequential magnetic separation. The Royal Society of Chemistry 2013.
Insight into carbon nanotubes-template reaction at high temperature
Hu, Long,Li,Ding,Tang,Qi
, p. 271 - 276 (2004)
Different types of carbon nanotubes (CNTs), including multi-walled CNTs, single-walled CNTs bundles, isolated single- or double-walled CNTs and nano-bamboo structured CNTs, were used as the templates to synthesize SiC and BN one-dimensional nanostructures
New Phase of sp3-Bonded BN: The 5H Polytype
Komatsu, Shojiro,Okada, Katsuyuki,Shimizu, Yoshiki,Moriyoshi, Yusuke
, p. 3289 - 3291 (1999)
A new phase of sp3-bonded BN, that is, 5H polytype, has been found. The representative lattice parameters a and c were determined to be 2.528 and 10.407 Angstroem, respectively. The new BN phase was prepared by chemical vapor deposition assisted with 193 nm laser irradiation of the surface. Source gases were diborane and ammonia diluted in argon and hydrogen. The substrate temperature was 850 degC.
X-ray absorption near edge structure study of BN nanotubes and nanothorns
Choi, Hyun Chul,Bae, Seung Yong,Jang, Woo Sung,Park, Jeunghee,Song, Ha Jin,Shin, Hyun-Joon
, p. 7007 - 7011 (2005)
Two boron nitride (BN) nanostructures, the bamboo-like nanotubes and nanothoms where the nanosize h-BN layers are randomly stacked looking like thorns, were synthesized selectively via thermal chemical vapor deposition of B/B2O3 under the NH3 flow at 1200?°C. Electron energy-loss spectroscopy reveals the N-rich h-BN layers with a ratio of B/N = 0.75-0.85. Angle-resolved X-ray absorption near edge structure of these two N-rich nanostructures has been compared with that of h-BN microcrystals. The ??* transition in the N K-edge shifts to the lower energy by 0.8-1.0 eV from that of h-BN microcrystals, and the second-order signals of N ls electrons become significant. We suggest that the N enrichment would decrease the band gap of nanostructures from that of h-BN microcrystals. The Raman spectrum shows the peak broadening due to the defects of N-rich h-BN layers. ? 2005 American Chemical Society.
Characterization of boron nitride films deposited from BCl3-NH3-H2 mixtures in chemical vapour infiltration conditions
Cholet, V.,Vandenbulcke, L.,Rouan, J. P.,Baillif, P.,Erre, R.
, (1994)
Boron nitride (BN) thin films deposited by isopressure and isothermal chemical vapour infiltration (ICVI) from BCl3-NH3-N2 mixtures have been characterized from a physicochemical point of view as functions of both the deposition conditions and the destabilizing action of moisture. As-deposited (deposited at 773 K and post-treated at 1273 K), the BN films are turbostractic (d002 = 0.36 nm, Lc = 1.5 nm), have a low density (1.4 g cm-3) and contain oxygen (about 20 at%). A first oxygen content (191.5 eV by XPS) is inserted in the films during the CVI step in relation to the hygroscopy of intermediate solid products and the quasi-equilibrium between the formation of BN and B2O3. A second oxygen content (192.5 eV) is due to the hydrolysis of BN by moisture which induces a very drastic transformation of BN. This destabilization affects both boron and nitrogen atoms and leads to the formation of ammonium borate hydrates. Different post-treatments have been investigated to stabilize the BN films and it appears that nitriding under ammonia is the most efficient.
Formation of B, Al, Ga, and Si nitrides from their oxides: A reactive laser ablation study
Raina,Kulkarni,Rao
, p. 1271 - 1277 (2004)
Nitrides such as Si3N4 and GaN are made by the reaction of the respective oxide with N2 or NH3. In order to understand the mechanism of formation of nitrides, reactive laser ablation of B2O3, Al2O3, Ga2O 3, and SiO2 in pure form, as well as in mixture with carbon, has been carried out in an atmosphere of nitrogen or ammonia in a pulsed supersonic jet. The reaction of N2 with SiO2 gives nitridic species such as Si2Ny (y≤5) in the vapor phase. On reaction with N2 in the presence of carbon, B 2O3 and Ga2O3 yield species of the type BxNy and GaNy, respectively. Nitridic species are preponderant in the reaction with ammonia only in the case of SiO2. Al2O3 predominantly gives oxynitridic species under the reaction conditions examined.
A low-temperature coreduction route to boron nitride flakes and hollow spheres
Chen, Luyang,Gu, Yunle,Shi, Liang,Yang, Zeheng,Ma, Jianhua,Qian, Yitai
, p. 144 - 145 (2004)
Boron nitride flakes and hollow spheres were synthesized by coreduction of NH4Cl and BBr3 using sodium as reductant. X-ray powder diffraction (XRD) pattern could be indexed as hexagonal BN. The X-ray photoelectron spectra (XPS) were used to determine the composition ratio, which is B:N = 1:1.05. The transmission electron microscopy (TEM) images showed flake-like and hollow spherical morphology.
Composition and microstructure of chemically vapor-deposited boron nitride, aluminum nitride, and boron nitride + aluminum nitride composites
Hanigofsky,More,Lackey,Lee,Freeman
, p. 301 - 305 (1991)
The composition and microstructure of dispersed-phase ceramic composites containing BN and AlN as well as BN and AlN single-phase ceramics prepared by chemical vapor deposition have been characterized using X-ray diffraction, scanning electron microscopy, electron microprobe, and transmission electron microscopy techniques. Under certain processing conditions, the codeposited coating microstructure consists of small single-crystal AlN fibers (whiskers) surrounded by a turbostatic BN matrix. Other processing conditions resulted in single-phase films of AlN with a fibrous structure. The compositions of the codeposits range from 2 to 50 mol% BN, 50 to 80 mol% AlN with 7% to 25% oxygen impurity as determined by electron microprobe analysis.
