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.

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.

scholarly journals Investigation of the γ′ Precipitates Dissolution in a Ni-Based Superalloy During Stress-Free Short-Term Annealing at High Homologous Temperatures

2021 ◽  
Author(s):  
Łukasz Rakoczy ◽  
Małgorzata Grudzień-Rakoczy ◽  
Fabian Hanning ◽  
Grzegorz Cempura ◽  
Rafał Cygan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Short Term ◽  
X Ray ◽  
Transmission Electron ◽  
Thermodynamic Simulations ◽  
The Matrix ◽  
Increasing Temperature

AbstractThe equiaxed Ni-based superalloy René 108 was subjected to short-term annealing at five temperatures between 900 °C and 1100 °C. The phase composition, phase lattice parameters, microstructure, stereological parameters, and chemical composition of γ′ precipitates were investigated by thermodynamic simulations, X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Analysis of the γ and γ′ lattice parameters using the Nelson-Riley extrapolation function showed that the misfit parameter for temperatures 900 °C to 1050 °C is positive (decreasing from 0.32 to 0.11 pct). At 1100 °C, the parameter becomes negative, δ = − 0.18 pct. During the short-term annealing, γ′ precipitates dissolution occurred progressing more rapidly with increasing temperatures. The surface fraction of γ′ precipitates decreased with increasing temperature from 0.52 to 0.34. The dissolution of γ′ precipitates did not only proceed through uninterrupted thinning of each individual precipitate, but also included more complex mechanisms, including splitting. Based on transmission electron microscopy, it was shown that after γ′ precipitates dissolution, the matrix close to the γ/γ′ interface is strongly enriched in Co and Cr and depleted in Al.

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.

Structure of Oxides Grown on Zr-20Nb Alloy

1994 ◽  
Vol 357 ◽  
Author(s):  
O.T. Woo ◽  
D.J. Lockwood ◽  
Y.P. Lin ◽  
V.F. Urbanic
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Raman Spectra ◽  
High Symmetry ◽  
X Ray Diffraction ◽  
Short Term ◽  
X Ray ◽  
Transmission Electron

AbstractOxides grown on Zr-20Nb were characterized by Raman Spectroscopy (RS), X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). These oxides were steamformed at 400°C, water-formed at 360 °C and at 300 °C, and air-grown at 400°C. For the oxides grown after relatively short exposures at 360°C and at 400°C, Raman spectra revealed broad peaks at 260 and 660 cm− indicating a crystal structure with high symmetry. Comparison with reference Raman spectra of cubic (c), tetragonal (t), and monoclinic (m) ZrO2 suggested that the oxide was predominantly nearly-cubic (tetragonal with c/a ratio ≈ 1), with minor amounts of moxide. The tetragonality is found to be consistent with TEM analyses and XRD results which showed the presence of a doublet near 2θ ° 74°. The crystal structure in the short-term exposed oxides is interpreted in terms of a tetragonal distortion arising from the displacement of oxygen atoms within the cubic ZrO2 crystal structure. For oxides grown after longer periods of exposure at 300°C and at 400°C, RS and XRD indicate increased amounts of m-oxide.

X-Ray Diffraction Study of Cubic Boron Nitride Grown Epitaxially on Silicon

1990 ◽  
Vol 202 ◽  
Author(s):  
G. L. Doll ◽  
J. A. Sell ◽  
A. Wims ◽  
C. A. Taylor ◽  
R. Clarke
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Boron Nitride ◽  
Cubic Boron Nitride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Matching ◽  
Excimer Laser Ablation ◽  
Transmission Electron ◽  
Boron Nitride Films

ABSTRACTWe report the growth of boron nitride films on (001), (110), and (111) faces of silicon using the method of pulsed excimer laser ablation. The structure of the Alms grown on the (001) and (110) orientations of Si is cubic zincblende with a lattice constant of 3.619 Å. The films were found to be heteroepitaxial on silicon (001) with the cubic BN (100) axes parallel to Si (100), as characterized by x-ray diffraction and high-resolution transmission electron microscopy. In that system, we find evidence for an unusual 3:2 commensurate lattice matching. The films appear to cubic but randomly oriented on the Si (110), and no evidence for crystallinity is found for films grown on Si (111).

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

Multi-scale Investigation of Heterogeneous Swift Heavy Ion Tracks in Stannate Pyrochlore

2021 ◽  
Author(s):  
Eric O'Quinn ◽  
Cameron Tracy ◽  
William F. Cureton ◽  
Ritesh Sachan ◽  
Joerg C. Neuefeind ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heavy Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Modifications ◽  
Multi Scale ◽  
Ion Tracks ◽  
Swift Heavy Ion ◽  
Transmission Electron

Er2Sn2O7 pyrochlore was irradiated with swift heavy Au ions (2.2 GeV), and the induced structural modifications were systematically examined using complementary characterization techniques including transmission electron microscopy (TEM), X-ray diffraction...

Detonation Synthesis of Nano-Size Materials

1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.

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