نتایج جستجو برای: cubic boron nitride

تعداد نتایج: 62709  

2001
D. N. Jayawardane Chris J. Pickard

A comparison between experimental and theoretical electron Energy Loss Near Edge Structure (ELNES) of B and N K-edges in cubic boron nitride is presented. The electron energy loss spectra of cubic boron nitride particles were measured using a scanning transmission electron microscope. The theoretical calculation of the ELNES was performed within the framework of density functional theory includ...

2005
S. Reich A. C. Ferrari A. Loiseau

We measured firstand second-order Raman scattering in cubic and hexagonal boron nitride using excitation energies in the visible and in the UV. The nonresonant first-order Raman susceptibilities for cubic and hexagonal BN are 1 and 10 Å2, respectively. Raman scattering is thus very powerful in detecting the hexagonal phase in mixed thin boron nitride films. In cubic BN the constant Raman sucsep...

2004
Hangsheng Yang Toyonobu Yoshida

Chemical species in plasma are crucial for understanding the mechanism of cubic boron nitride film vapor phase deposition and controlling the film structure. In this study, the plasma condition for cubic boron nitride deposition by low-pressure inductively coupled plasmaenhanced chemical vapor deposition using B2H6, N2, and Ar as reactant gases has been diagnosed by a quadrupole mass spectromet...

Journal: :International journal of toxicology 2015
Monice M Fiume Wilma F Bergfeld Donald V Belsito Ronald A Hill Curtis D Klaassen Daniel C Liebler James G Marks Ronald C Shank Thomas J Slaga Paul W Snyder F Alan Andersen

The Cosmetic Ingredient Review Expert Panel (Panel) assessed the safety of boron nitride which functions in cosmetics as a slip modifier (ie, it has a lubricating effect). Boron nitride is an inorganic compound with a crystalline form that can be hexagonal, spherical, or cubic; the hexagonal form is presumed to be used in cosmetics. The highest reported concentration of use of boron nitride is ...

2013
E. Franke Mathias Schubert T. E. Tiwald J. A. Woollam M. Schubert

Infrared ellipsometry on hexagonal and cubic boron nitride thin films" (1997).

1999
C. A. Taylor R. Clarke Harrison M. Randall

We report results from cathodoluminescence spectroscopy of boron nitride films grown on Si(100) substrates by ion-source-assisted magnetron sputtering of a hexagonal BN target. Three main peaks are observed in the near-band-gap region for hexagonal boron nitride films at energies of 4.90,5.31, and 5.50 eV We also report deep-level emission spectra of predominantly cubic boron nitride films whic...

2010
S K Singhal B P Singh

Sintering of cubic boron nitride (cBN) was carried out by subjecting fine powders of cBN to high pressures and temperatures (P = 50-60 kb, T = 1200-1500°C ) in the presence of boron carbide as the main binding material together with a small amount of aluminium nitride. The composites were characterized by X-ray diffraction, scanning electron microscopy, FTIR, Raman Spectroscopy and microhardnes...

2001
D. N. Jayawardane Chris J. Pickard M. C. Payne

A comparison between experimental and theoretical electron energy loss near edge structure ~ELNES! of B and N K edges in cubic boron nitride is presented. The electron energy loss spectra of cubic boron nitride particles were measured using a scanning transmission electron microscope. The theoretical calculation of the ELNES was performed within the framework of density functional theory includ...

Journal: :Entropy 2015
Xiao-Fei Guo Bin Xu Wen Zhang Mei-Zhe Lv Hong-Mei Yang Xiao-Hong Fan

The nucleation of cubic boron nitride (cBN) single crystals synthesized with lithium nitride (Li3N) as a catalyst under high pressure and high temperature (HPHT) was analyzed. Many nanometer-sized cubic boron nitride nuclei formed in the near surface layer, as detected by high resolution transmission electron microscopy. Based on the experiment results, the transformation kinetics is described ...

Journal: :Molecules 2016
Oleksandr O Kurakevych Vladimir L Solozhenko

The aim of the present review is to highlight the state of the art in high-pressure design of new advanced materials based on boron nitride. Recent experimental achievements on the governing phase transformation, nanostructuring and chemical synthesis in the systems containing boron nitride at high pressures and high temperatures are presented. All these developments allowed discovering new mat...

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