Preparation and Properties of a Compound in the B-C-N System

Hubác̆ek, Milan; Satô, Tadao

doi:10.1006/jssc.1995.1037

Cited by 111 publications

(38 citation statements)

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“…In the experiments described here, two starting materials were used: a novel turbostratic BN sample with a well-defined interlayer spacing (β-tBN) [22,23]; and a BN nanotube sample produced by arc discharge between HfB 2 electrodes in a nitrogen atmosphere [5]. Observations were carried out respectively in a field emission 300 kV analytical microscope (Jeol 3000F) and in a Jeol 4000FX (LaB 6 emission filament) transmission electron microscope.…”

Section: Methodsmentioning

confidence: 99%

Formation of small single-layer and nested BN cages under electron irradiation of nanotubes and bulk material

Stéphan

Bando

Loiseau

et al. 1998

Applied Physics A: Materials Science & Processing

213

115

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An experimental evidence for the formation of small BN cage-like molecules, under electron-irradiation experiments of BN samples, is presented. Depending on the starting material, either close-packed agglomerates of small "fullerenes", or small nested "fullerenes" with up to six layers are found as irradiation derivatives. The overall polyhedral shape of the BN cages is explained within the frame of the octahedral model previously proposed for BN analogs to fullerenes. The diameters of the smallest and most observed cages range from 0.4 to 0.7 nm, and are close to those of the B 12 N 12 , B 16 N 16 and B 28 N 28 octahedra which were predicted to be magic clusters for the BN system from electronic structure calculations.The discovery of the C 60 soccer ball [1] followed by that of larger fullerenes and carbon nanotubes [2] raised the curtain on a new class of nano-objects based on layered materials with predicted unique physical properties. Recently, the synthesis of BN [3][4][5][6], BCN [7,8], and MoS 2 [9] nanotubes and closed shell nanoparticles has generalized the idea already admitted for carbon that for a small assembly of atoms the network bends and curls into a close structure in order to eliminate the highly unfavorable dangling bonds. Nested concentric BN polyhedra have been successfully synthesized by reaction of BCl 3 with NH 3 in a laser beam [10,11]. However, in spite of theoretical predictions for the stability of the hybrid B 24 C 12 N 24 molecule [12] and the B 12 N 12 , B 16 N 16 , B 28 N 28 molecules [13,14], there has been, so far, no experimental evidence for the stability of structures analogous to C 60 and other small carbon fullerenes in layered materials other than graphite.Strong irradiation in an electron microscope allows structural fluidity and a rearrangement of the structure caused by the momentum transfer of high-energy electrons to the nuclei (knock-on collisions). It is now well known that carbon material, whatever its initial structural state -namely amorphous, turbostratic or well-graphitized, bulk crystallites, nanocages, or nanotubes -can be transformed into onion-like structures when submitted to such intense electron irradiation [15,16]. Carbon onions can have very different sizes and consist of concentric polyhedral fullerene cages; single-or double-layer small fullerene cages can also be formed [17]. On the other hand, only disordered spherical layered structures with incompletely closed layers were shown to form under electron irradiation of crystalline BN [18], MoS 2 crystals [19], and turbostratic BC 2 N [20]. We present transformations obtained when submitting to intense irradiation regimes two kinds of BN samples, a turbostratic BN sample and a BN nanotube powder. Depending on the starting material, two different irradiation products are observed: small nested polyhedra or close-packed arrangements of small single-layer cage-like clusters. The size and shape of the smallest observed cage is compared to that of the smallest high-symmetry polyhedral clusters predicted t...

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Section: Methodsmentioning

confidence: 99%

Formation of small single-layer and nested BN cages under electron irradiation of nanotubes and bulk material

Stéphan

Bando

Loiseau

et al. 1998

Applied Physics A: Materials Science & Processing

213

115

View full text Add to dashboard Cite

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“…The broad reflections observed in the diffraction patterns (marked with *) are due to the turbostratic nature of the BCN [46,47]. The results of XPS measurements of the BC2N and BC4N have been reported in a previous study [48].…”

Section: Resultsmentioning

confidence: 53%

“…The amount of carbon in the final ceramics equals 45 wt % for BC 2 N and 65 wt % for BC 4 N. Figure 1, indicating the amorphous nature of both BC 2 N and BC 4 N compositions. The broad reflections observed in the diffraction patterns (marked with *) are due to the turbostratic nature of the BCN [46,47].…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Li Storage Properties of Carbon-Rich B–C–N Ceramics

Bhat

Sasikumar

Molina‐Luna

et al. 2016

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Amorphous BCN ceramics were synthesized via a thermal conversion procedure of piperazine-borane and pyridine-borane. The synthesized BC 2 N and BC 4 N ceramics contained, in their final amorphous structure, 45 and 65 wt % of carbon, respectively. Elemental analysis revealed 45 and 65 wt % of carbon for BC 2 N and BC 4 N, respectively. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed the amorphous nature of studied compounds. Lateral cluster size of carbon crystallites of 7.43 and 10.3 nm for BC 2 N and BC 4 N, respectively, was calculated from Raman spectroscopy data. This signified a higher order of the carbon phase present in BC 4 N. The electrochemical investigation of the low carbon BC 2 N composition as anodes for Li-ion batteries revealed initial capacities of 667 and 235 mAh¨g´1 for lithium insertion/extraction, respectively. The material with higher carbon content, BC 4 N, disclosed better reversible lithium storage properties. Initial capacities of 1030 and 737 mAh¨g´1 for lithium insertion and extraction were recovered for carbon-rich BC 4 N composition. Extended cycling with high currents up to 2 C/2 D revealed the cycling stability of BC 4 N electrodes. Cycling for more than 75 cycles at constant current rates showed a stable electrochemical behavior of BC 4 N anodes with capacities as high as 500 mAh¨g´1.

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“…As a consequence of this, the transport critical transition temperature values of our samples do not vary significantly but the critical current density in magnetic fields decrease dramatically. Nano-particles of h-BN have H and OH attached to their open ends [45]. The amount of H and OH introduced into MgB2 samples with h-BN doping increases as the particle size decreases due to increasing surface/volume ratio.…”

Section: Resultsmentioning

confidence: 99%

Effect of different-sized h-BN nano-particles on some properties of MgB2 superconductors

Karaboğa

Yetiş

Öz

et al. 2016

J Mater Sci: Mater Electron

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The present study reports the effect of hexagonal boron nitride (h-BN) doping on the superconducting properties of bulk MgB 2 samples. Structural, electrical and magnetic properties of 3 wt% h-BN doped MgB 2 samples are studied in terms of three different sized h-BN nanoparticles. The results show that h-BN doping has no significant change on critical transition temperature (±0.5 K deviation), but decreases the magnetic J c with increasing the h-BN particle size. Among the doped samples, a highest J c (T = 10 K) value of 1.8 9 10 4 A/cm 2 is achieved for the sample doped with the smallest sized h-BN at zero external magnetic field but it is still lower than the 2.5 9 10 4 A/cm 2 obtained for the un-doped sample. In the scope of this study, it is investigated whether or not the nano-sized h-BN particle is a possible candidate to improve the pinning properties of the MgB 2 sample and we suggest that particle size is very important parameter in h-BN doping into MgB 2 .

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Preparation and Properties of a Compound in the B-C-N System

Cited by 111 publications

References 0 publications

Formation of small single-layer and nested BN cages under electron irradiation of nanotubes and bulk material

Formation of small single-layer and nested BN cages under electron irradiation of nanotubes and bulk material

Electrochemical Li Storage Properties of Carbon-Rich B–C–N Ceramics

Effect of different-sized h-BN nano-particles on some properties of MgB2 superconductors

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