Microstructure and Chemical Composition of Boron Nitride Fibers

2013 ◽  
Vol 591 ◽  
pp. 16-19 ◽  
Author(s):  
Ru Li ◽  
Chuan Shan Li ◽  
Jie Tang ◽  
Jian Xin Tang ◽  
Xiao Yong Du ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Boron Nitride ◽  
Photoelectron Spectroscopy ◽  
Hexagonal Boron Nitride ◽  
Energy Dispersive Spectrum ◽  
Test Method ◽  
Ir Absorption ◽  
X Ray Diffraction ◽  
Modified Technique ◽  
X Ray

Boron nitride(BN) fibres were synthesized by modified technique of Economy’s method. The products were characterized by X-ray diffraction (XRD), fourier transform infrared (FT-IR) absorption spectroscopy, field-emission scanning electron microscopy (FE-SEM), X-ray energy dispersive spectrum (EDS) and X-ray photoelectron spectroscopy (XPS). The results showed that BN fibers were mainly hexagonal boron nitride (h-BN) with diameters of 5-8 μm and the major compositions of BN fibers are B and N with a very small amount of O and C. At last, the chemical composition of samples were determined by the chemical analysis test method like GB/T 16555-2008 and GJB 507-1998.

Effects of CaB2O4 Content on the Sintering Behavior of Hexagonal Boron Nitride

2011 ◽  
Vol 675-677 ◽  
pp. 131-134
Author(s):  
Yu Xia Cao ◽  
Ling Zhong Du ◽  
Wei Gang Zhang
Keyword(s):  
Boron Nitride ◽  
Diffraction Analysis ◽  
Apparent Density ◽  
Cross Sections ◽  
Hexagonal Boron Nitride ◽  
Sintering Behavior ◽  
Rockwell Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes

CaB2O4 was added into hexagonal boron nitride (hBN) to improve the sintering behaviors of hBN. CaB2O4 and hBN were mixed and then pressed into plates. The plates were sintered at 2000°C for 5h under a N2 ambience. The phase compositions with different CaB2O4 contents were examined with X-ray diffraction analysis. The fracture cross-sections of the hBN plates were investigated by SEM. The apparent density and Rockwell hardness were also measured. The results show that the hBN particles had a plate-like shape and the grain sizes of hBN increased with increasing CaB2O4 contents. The apparent density and Rockwell hardness decreased with increasing CaB2O4 contents. When the CaB2O4 content was 15(wt) %, the hBN has the average grain sizes of 3μm in diameter and 200nm in thickness, the apparent density of 1.06 g/cm3 and the Rockwell hardness of 3, respectively.

CHEMICAL COMPOSITION AND CRYSTALLINE PHASES IN F-DOPED TIN OXIDE FILMS GROWN BY DC REACTIVE SPUTTERING

2001 ◽  
Vol 15 (17n19) ◽  
pp. 634-638 ◽  
Author(s):  
A. MARTEL ◽  
F. CABALLERO-BRIONES ◽  
A. IRIBARREN ◽  
R. CASTRO-RODRÍGUEZ ◽  
P. BARTOLO-PÉREZ ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Molar Fraction ◽  
Reactive Sputtering ◽  
Simultaneous Presence ◽  
X Ray Diffraction ◽  
Structural Variations ◽  
X Ray ◽  
Tin Oxide Films

We study by x-ray diffraction (XRD) the structural variations on a series of SnOx:F films grown by dc reactive sputtering from a metallic tin target in an Ar- O 2-Freon plasma. We found that the films tend to be crystalline when the stoichiometry approaches to that of SnO or SnO 2, being amorphous in between. We fitted the x-ray diffractograms and found that films are composed by a mixture of compounds, i.e. SnO, Sn 3 O 4, Sn 2 O 3 and SnO 2, given by the simultaneous presence of Sn +2 and Sn +4. From the analysis of the deconvoluted areas under the x-ray diffractograms we calculate the Sn +2/ Sn and Sn +4/ Sn molar fraction present in the films. The same calculations are done for the x-ray photoelectron spectroscopy (XPS) results. By applying a combinatory model we fitted the general behavior of SnO x films with different oxygen content versus the Sn +2/ Sn and Sn +4/ Sn molar fraction. Both XRD and XPS results are compared with the theoretical curve, showing a well agreement.

scholarly journals AB-stacked nanosheet-based hexagonal boron nitride

2021 ◽  
Vol 77 (2) ◽  
Author(s):  
Jae-Kap Lee ◽  
Jin-Gyu Kim ◽  
K. P. S. S. Hembram ◽  
Seunggun Yu ◽  
Sang-Gil Lee
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Metastable Phase ◽  
Stacking Sequence ◽  
Lateral Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Crystalline Growth

Hexagonal boron nitride (h-BN) has been generally interpreted as having an AA stacking sequence. Evidence is presented in this article indicating that typical commercial h-BN platelets (∼10–500 nm in thickness) exhibit stacks of parallel nanosheets (∼10 nm in thickness) predominantly in the AB sequence. The AB-stacked nanosheet occurs as a metastable phase of h-BN resulting from the preferred texture and lateral growth of armchair (110) planes. It appears as an independent nanosheet or unit for h-BN platelets. The analysis is supported by simulation of thin AB films (2–20 layers), which explains the unique X-ray diffraction pattern of h-BN. With this analysis and the role of pressure in commercial high-pressure high-temperature sintering (driving nucleation and parallelizing the in-plane crystalline growth of the nuclei), a growth mechanism is proposed for 2D h-BN (on a substrate) as `substrate-induced 2D growth', where the substrate plays the role of pressure.

scholarly journals Catalyst-Free Bottom-Up Synthesis of Few-Layer Hexagonal Boron Nitride Nanosheets

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shena M. Stanley ◽  
Amartya Chakrabarti ◽  
Joshua J. DeMuth ◽  
Vanessa E. Tempel ◽  
Narayan S. Hosmane
Keyword(s):  
Electron Microscopy ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
X Ray Diffraction ◽  
Bottom Up ◽  
X Ray ◽  
Boron Nitride Nanosheets ◽  
Catalyst Free ◽  
Transmission Electron ◽  
Novel Catalyst

A novel catalyst-free methodology has been developed to prepare few-layer hexagonal boron nitride nanosheets using a bottom-up process. Scanning electron microscopy and transmission electron microscopy (both high and low resolution) exhibit evidence of less than ten layers of nanosheets with uniform dimension. X-ray diffraction pattern and other additional characterization techniques prove crystallinity and purity of the product.

Sonochemical Functionalization of Boron Nitride Nanomaterials

MRS Advances ◽  
2019 ◽  
Vol 5 (14-15) ◽  
pp. 709-716
Author(s):  
Haley B. Harrison ◽  
Jeffrey R. Alston
Keyword(s):  
Thermal Stability ◽  
Boron Nitride ◽  
Photoelectron Spectroscopy ◽  
Colloidal Stability ◽  
Hexagonal Boron Nitride ◽  
Boron Nitride Nanotubes ◽  
Covalent Attachment ◽  
Covalent Functionalization ◽  
X Ray ◽  
Ft Ir

AbstractBoron nitride nanotubes (BNNTs) and hexagonal boron nitride platelets (h-BNs) have received considerable attention for aerospace insulation applications due to their exceptional chemical and thermal stability. Presently, making BN nanomaterials compatible with polymer and composite matrices is challenging. Due to their inert and highly stable structure, h-BN and BNNTs are difficult to covalently functionalize. In this work, we present a novel sonochemical technique that enables covalent attachment of fluoroalkoxy substituents to the surface of BN nanomaterials in a controlled and metered process. Covalent functionalization is confirmed via colloidal stability analysis, FT-IR, and x-ray photoelectron spectroscopy (XPS).

Sliding wear and friction of Si3N4-SiC-based ceramic composites containing hexagonal boron nitride

1998 ◽  
Vol 212 (5) ◽  
pp. 381-387 ◽  
Author(s):  
R Westergård ◽  
A Åhlin ◽  
N Axén ◽  
S Hogmark
Keyword(s):  
Boron Nitride ◽  
Photoelectron Spectroscopy ◽  
Friction And Wear ◽  
Hexagonal Boron Nitride ◽  
Ceramic Composites ◽  
Wear Behaviour ◽  
Friction Coefficients ◽  
X Ray ◽  
Wear Rates ◽  
Low Level

The friction and wear behaviour of a series of new Si3N4-SiC-based ceramic composites, intended for face seal applications, has been investigated with cylinder-on-disc equipment. In particular, the influence of water and vapour on the friction, wear and tribo-film formation has been studied. The ceramics consisted of Sis3N4 and SiC in the proportions 7:3, to which 0, 4 or 8 wt% of hexagonal boron nitride was added as a solid lubricant. All specimens were produced by hot isostatic pressing. X-ray diffraction and scanning electron microscopy were used to reveal the phase composition and microstructure respectively. The hardness was assessed using Vickers indentation. The chemical composition of the tribo-films was studied with X-ray photoelectron spectroscopy. The major results are that both friction and wear showed distinct low and high levels. The high friction level corresponded to friction coefficients between 0.4 and 0.9 and wear rates between 104 and 105 μm3/Nm. The low level corresponded to friction coefficients between 0.02 and 0.1, and wear rates between 10 and 103 μm3/Nm. When water or saturated vapour was present in the tribo-system, both friction and wear were low. All surfaces produced in the low level were smooth, covered by a thin well-adhering tribo-film while the high level resulted in strongly oxidized and patchy tribo-film covered by wear particles.

scholarly journals Exfoliation of Hexagonal Boron Nitride (h-BN) in Liquide Phase by Ion Intercalation

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 716 ◽  
Author(s):  
Danae Gonzalez Ortiz ◽  
Celine Pochat-Bohatier ◽  
Julien Cambedouzou ◽  
Mikhael Bechelany ◽  
Philippe Miele
Keyword(s):  
Aqueous Solution ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
X Ray ◽  
Boron Nitride Nanosheets ◽  
Green Approach ◽  
Step Procedure ◽  
Ion Intercalation

A green approach to prepare exfoliated hexagonal boron nitride nanosheets (h-BNNS) from commercially pristine h-BN involving a two-step procedure was investigated. The first step involves the dispersion of pristine h-BN within an aqueous solution containing gelatin and potassium or zinc chloride using a sonication method. The second involves the removal of larger exfoliated h-BNNS through a centrifugation procedure. The exfoliation was caused not only by the sonication effect but also by intercalation of K+ and Zn2+ ions. Transmission electronic microscopy, X-ray diffraction and Raman spectroscopy techniques show that the obtained h-BNNS generally display a thickness of about a few (2–3) layers with an exfoliation efficiency as high as 16.3 ± 0.4%.

Microstructure, Mechanical and Tribological Properties of Reactive Magnetron Sputtered Titanium Carbide Coatings

2007 ◽  
Author(s):  
Kyriaki Polychronopoulou ◽  
Claus Rebholz ◽  
Nicholaos G. Demas ◽  
Andreas A. Polycarpou ◽  
Lefki Theodorou ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Carbon Content ◽  
Tribological Properties ◽  
Photoelectron Spectroscopy ◽  
Reactive Magnetron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wear Rates ◽  
Mechanical And Tribological Properties ◽  
Carbide Coatings

This study describes the correlation between the microstructure, mechanical and tribological properties of Ti1−xCx coatings (with x being in the range of 0–0.5), deposited by reactive magnetron sputtering from a Ti target in Ar/C2H2 mixtures at ∼200 °C. The mechanical and tribological properties were found to strongly depend on the chemical composition and the microstructure present. Very dense structures and highest hardness and elastic modulus, combined with low wear rates, were observed for films with chemical composition close to TiC. X-ray diffraction (XRD) studies showed that the coating deposited at high C2H2 flow rates composed of randomly oriented TiC crystallites. Morphological investigations by scanning electron microscopy (SEM) indicate that the morphology is strongly dependent on the carbon content of the coating. Coatings composition and bonding environment was investigated using X-ray photoelectron spectroscopy (XPS). Both the mechanical properties and tribological performance of the coatings were found to be dependent on carbon content.

scholarly journals Получение гетерогенных наночастиц Al/BN в микроволновой плазме

2020 ◽  
Vol 46 (10) ◽  
pp. 25
Author(s):  
Ш. Корте ◽  
М.К. Кутжанов ◽  
А.М. Ковальский ◽  
А.С. Конопацкий ◽  
Д.Г. Квашнин ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Boron Nitride ◽  
Microwave Plasma ◽  
Hexagonal Boron Nitride ◽  
Shear Stresses ◽  
X Ray Diffraction ◽  
Short Term ◽  
X Ray ◽  
Transmission Electron

In this work, the interaction of a mixture of Al and BN nanopowder with hydrogen microwave plasma was studied. Using X-ray diffraction analysis, scanning and transmission electron microscopy, the formation of AlN and AlB2 nanocrystals as a result of short-term (~ 30 ms) interaction of Al vapor with h-BN was established. Obtained results also indicate the formation of hydrogenated hexagonal boron nitride h-BN-H. The critical shear stresses were calculated for the interfaces between BN and Al, AlB2, and AlN. Approaches for increasing the strength of the composite materials based on hexagonal boron nitride and aluminum are discussed.

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