Phases and Microstructures of Carbon-Implanted Niobium

1988 ◽  
Vol 128 ◽  
Author(s):  
J. S. Huang ◽  
R. G. Musket ◽  
M. A. Wall
Keyword(s):  
Solubility Limit ◽  
Carbon Ions ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
Auger Electron Spectroscopy Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Glancing Angle ◽  
Second Phases ◽  
Many Particles

ABSTRACTPolycrystalline niobium was implanted with 200, 100, and 50 keV carbon ions to create a uniform distribution of carbon over a thickness of about 0.25 μm. Samples implanted with calculated carbon content of 0.6, 1.9, 5.8, and 16 atomic percent were prepared, and the uniformity of the carbon distribution with depth was confirmed by Auger electron spectroscopy analysis. Glancing-angle X-ray diffraction analysis and transmission electron microscopy were used to characterize the phases and microstructures formed. The results indicated that no detectable second phases were present except on the surfaces where an amorphous phase and many particles were formed from contamination. Despite the low equilibrium solubility limit of carbon in Nb, we have created metastable solid solutions of Nb and C with carbon contents as high as 16 at.%.

scholarly journals Formation of Niobium Carbides in High-Dose Carbon-Ion-Implanted and Annealed Niobium

1989 ◽  
Vol 157 ◽  
Author(s):  
J. S. Huang
Keyword(s):  
Narrow Range ◽  
Nucleation And Growth ◽  
High Dose ◽  
Carbon Ions ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Glancing Angle ◽  
Total Fluence

ABSTRACTPolycrystalline niobium was implanted with 200-keV C+ ions to a total fluence of 7 × 1017 carbon ions per cm2 (C/cm2). Auger electron spectroscopy (AES) analysis showed that the carbon concentration varied from 5 to 50 at.% within a depth of about 4000 Å. Glancing-angle x-ray diffraction analysis (XRDA) and transmission electron microscopy (TEM) analysis indicated that no Nb2C phase was formed and that a buried fee NbC layer was formed in the region where carbon content exceeds about 40 at.%. The absence of Nb2C was attributed to its narrow range of solubility for carbon and the low diffusivity of carbon atoms. The possibility of the NbC precipitation by nucleation and growth or by a diffusionless martensitic transformation is discussed. When the implanted samples were annealed at 1273 K for 1 h, an orthorhombic Nb2C phase formed as spherical precipitates and the implanted carbon redistributed.

Preparation and characterization of CuInS2 nanorods and nanotubes from an elemental solvothermal reaction

2001 ◽  
Vol 16 (10) ◽  
pp. 2805-2809 ◽  
Author(s):  
Yang Jiang ◽  
Yue Wu ◽  
Shengwen Yuan ◽  
Bo Xie ◽  
Shuyuan Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Electron Transfer Reaction ◽  
Solvothermal Reaction ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Transmission Electron

A simple and convenient solvothermal reaction has been developed to produce CuInS2 nanorods and nanotubes from the elements in ethylenediamine at 280 °C. The products were characterized by x-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, scanning electron microscopy, and x-ray photoelectron spectroscopy. Analysis shows that the coordinating ability of ethylenediamine and the existence of liquid In may play important roles in the growth of one-dimension nanocrystallites and the electron-transfer reaction. In addition, spherical CuInS2 micrometer particles were obtained at 350 °C.

Short Term Oxidation of a Ti-46Al-8Nb Alloy at 700°C in Air

2010 ◽  
Vol 636-637 ◽  
pp. 485-490 ◽  
Author(s):  
Paul Erve T. Ngnekou ◽  
Marie Christine Lafont ◽  
François Senocq ◽  
Jacques Lacaze ◽  
Bernard Viguier
Keyword(s):  
Electron Microscopy ◽  
Total Duration ◽  
Outer Part ◽  
Parabolic Rate Constant ◽  
Oxidation Behaviour ◽  
X Ray Diffraction ◽  
Short Term ◽  
X Ray ◽  
Transmission Electron ◽  
Glancing Angle

Thermogravimetry was used to study the oxidation behaviour of a lamellar Ti46Al8Nb alloy during holding at 700°C in synthetic air. A parabolic plot of the oxidation kinetics shows three different regimes over the total duration (50 h) of the tests corresponding to decreasing values of the parabolic rate constant. The oxide scale was characterized by glancing-angle X-Ray diffraction and transmission electron microscopy. The scale was found to be bi-layered with an outer part that consists of amorphous aluminium rich oxide whilst the inner layer is made of very small cristalites of titania distributed in the same amorphous oxide.

scholarly journals Effects of barium substitution on the sintering behavior, dielectric properties of Ca2Nb2O7 ferroelectric ceramics

2017 ◽  
Vol 07 (02) ◽  
pp. 1750013 ◽  
Author(s):  
Chunchun Li ◽  
Huaicheng Xiang ◽  
Yuandong Qin ◽  
Liang Fang
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Secondary Phase ◽  
Solubility Limit ◽  
Ferroelectric Ceramics ◽  
Sintering Behavior ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray

Barium-doped Ca2Nb2O7 ceramics were prepared in the form of Ca[Formula: see text]BaxNb2O7 (0 [Formula: see text] 0.6) by solid-state reaction. The solubility limit of barium in Ca2Nb2O7 was found to be [Formula: see text] based on X-ray diffraction and Raman spectroscopy analysis. When [Formula: see text] 0.4, Ca[Formula: see text]BaxNb2O7 solid solutions with a monoclinic perovskites-like layered structure (PLS) were formed, whereas beyond [Formula: see text], a secondary phase CaNb2O6 was detected. The dielectric properties obviously depended on the barium substitution. With increasing barium amount, the dielectric constant increased from 33.5 for pure Ca2Nb2O7 to 38.6 for [Formula: see text] ([Formula: see text][Formula: see text]MHz). The Curie temperature ([Formula: see text] of the [Formula: see text] sample was 1280[Formula: see text][Formula: see text][Formula: see text]5[Formula: see text]C. The phase transition was confirmed to be the second order.

SYNTHESIS AND PHOTOLUMINESCENCE PROPERTIES OF MICRON-ALUMINA

2014 ◽  
Vol 21 (02) ◽  
pp. 1450031
Author(s):  
SHIHUA ZHAO ◽  
ZHENG WANG ◽  
MINGQUAN WANG ◽  
YUTING CUI ◽  
QUANLIN LIU
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electronic Transitions ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Preparation Methods ◽  
X Ray ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Many Particles

Micron-alumina is expected to be of new properties and applications owing to its different morphology structures, which is prepared by the conventional preparation methods. X-ray diffraction (XRD) patterns present that the micron-alumina has poly-crystalline structure. Scanning electron microscopy (SEM) shows that the micron-alumina looks like a bouquet of flowers and its surface is covered with much micron-strips. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) show that the micron-alumina is composed of many particles, which has polycrystalline structure. PL spectra display that emission peak of the micron-alumina centers at 301 nm, which attributes to the F + centers. A schematic drawing for electronic transitions in the excitation and emission processes is proposed.

scholarly journals Photo-Irradiated Biosynthesis of Silver Nanoparticles Using Edible MushroomPleurotus floridaand Their Antibacterial Activity Studies

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Ravishankar Bhat ◽  
Raghunandan Deshpande ◽  
Sharanabasava V. Ganachari ◽  
Do Sung Huh ◽  
A. Venkataraman
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Synthetic Procedure ◽  
Uv Visible

This is a report on photo-irradiated extracellular synthesis of silver nanoparticles using the aqueous extract of edible oyster mushroom (Pleurotus florida) as a reducing agent. The appearance, size, and shape of the silver nanoparticles are understood by UV-visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The X-ray diffraction studies, energy dispersive X-ray analysis indicate that particles are crystalline in nature. Fourier transform infrared spectroscopy analysis revealed that the nanoparticles are covered with biomoieties on their surface. As can be seen from our studies, the biofunctionalized silver nanoparticles thus produced have shown admirable antimicrobial effects, and the synthetic procedure involved is eco-friendly and simple, and hence high range production of the same can be considered for using them in many pharmaceutical applications.

Study on Preparation Process of ITO Nano-Powder by the Method of Ammonia Complexation

2012 ◽  
Vol 549 ◽  
pp. 441-444
Author(s):  
Li Da Sun ◽  
Du Shu Huang ◽  
Wei Liu ◽  
Yan Jiang ◽  
Rui Min Xiao ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Nucleation And Growth ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Nano Powder ◽  
Transmission Electron ◽  
Tin Oxides ◽  
Size And Morphology ◽  
Nucleation And Growth Mechanism

ITO (Indium Tin Oxides) nano-powder was prepared by the method of ammonia complexation. The chemical composition, morphology and crystal structure were characterized by X-ray diffraction (XRD) ,transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy analysis(XPS). Base on the nucleation and growth mechanism of the powder, the temperature of heat treatment impacting on size and morphology was discussed briefly. The results showed that the nano-ITO powder of particle size 20nm-40nm with well-pleasing particle shape and dispersion can be prepared at 800°C.

scholarly journals Structural and dielectric properties of sol–gel processed Ce-doped BaTi0.97Y0.03O3 ceramics

2021 ◽  
pp. 2150003
Author(s):  
Aziz Nfissi ◽  
Yahya Ababou ◽  
Mounir Belhajji ◽  
Salaheddine Sayouri ◽  
Taj-dine Lamcharfi
Keyword(s):  
Dielectric Properties ◽  
Sol Gel ◽  
Solubility Limit ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
A Value ◽  
Dielectric Resonance ◽  
Text Mode

Structural and dielectric properties of Ce-doped BaTi[Formula: see text]Y[Formula: see text]O3 powders, with the chemical formulation (Ba[Formula: see text]Ce[Formula: see text](Ti([Formula: see text]- Y[Formula: see text]O3 such as [Formula: see text] = 0%, 1%, 3%, 5%, 7% and 9%, produced by the sol–gel method, have been investigated. X-ray diffraction analysis showed that Ce[Formula: see text] ions incorporated Ba sites until [Formula: see text]= 7% indicating that this concentration represents a solubility limit of Ce[Formula: see text] ions in BaTi[Formula: see text]Y[Formula: see text]O3 matrix. Scanning electron microscopy (SEM) analysis showed a decrease in grain size down to the same concentration of 7%. Raman spectroscopy analysis showed the appearance of A[Formula: see text] mode, which we attributed to the effect of incorporation of Ce[Formula: see text] and Y[Formula: see text] in BaTiO3 matrix. Dielectric measurements revealed that doping with cerium lowers the temperature of permittivity maximum at the ferroelectric-to-paraelectric transition (FPT) of the BaTi[Formula: see text]Y[Formula: see text]O3 sample, and reaches a value that should be below 40[Formula: see text]C for [Formula: see text]= 9%. Moreover, the phenomenon of dielectric resonance was observed on all Ce-doped samples, which was not the case with other dopants as reported in the literature.

Formation of α-Fe2O3 Nanoflakes by Heating Fe in Air

2007 ◽  
Vol 121-123 ◽  
pp. 45-48 ◽  
Author(s):  
T. Yu ◽  
C.H. Sow ◽  
X.J. Xu ◽  
Y.W. Zhu ◽  
Chwee Teck Lim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Volume Ratio ◽  
Electron Field Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Glancing Angle ◽  
Electron Field ◽  
Method Show ◽  
Si Wafer

Flake-shaped hematite (α-Fe2O3) nanostructure has been successfully fabricated by using a hot-plate to directly heat Fe foil or Fe-coated substrates in air at 300oC. After heating, the surface of the samples was found to be populated with α-Fe2O3 nanoflakes. Such growth of α-Fe2O3 nanoflakes was very substrate-friendly. They can be formed on blank Si wafer, patterened Si, AFM tips, silica sphere, quartz, glass slide, Al foil and electrochemically etched W tip. The formation process and the final products were investigated by glancing angle x-ray diffraction (GAXRD), micro-Raman, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate the final products are single crystalline α-Fe2O3 nanoflakes vertically standing on the Fe3O4 film that acts as the precursor for growth of α-Fe2O3. The α-Fe2O3 nanoflakes formed by this method show very sharp tip with the tip radii as small as several nanometers and large surface to volume ratio. Such nanoflakes may be potentially useful as novel candidates for future electron field emission and gas senor devices. Furthermore, it is believed that this simple and substrates-friendly method is useful in extending the applications of α-Fe2O3 nanostructures.

Nanocrystalline SiC Formation From Sputter-Deposited Non-Equilibrium a-SixC1−x Alloys

1993 ◽  
Vol 298 ◽  
Author(s):  
Hong Wang ◽  
Z. Ma ◽  
L. H. Allen ◽  
J. M. Rigsbee
Keyword(s):  
X Ray Diffraction ◽  
Abrupt Increase ◽  
X Ray ◽  
Prolonged Annealing ◽  
Transmission Electron ◽  
Glancing Angle ◽  
Sputter Deposited ◽  
Deposited Film ◽  
Film Conductivity ◽  
Non Equilibrium

AbstractThere exists considerable interest in the synthesis of nanocrystalline SiC particles embedded in an a-SixC1−x:H matrix. This study investigated the formation of nanocrystalline SiC by annealing a non-equilibrium a-Si0.35C0.65 alloy sputter deposited onto oxidized (100) Si. Evolution of the microstructure was characterized by thin film sheet resistance measurements, glancing angle X-ray diffraction (GAXRD) and transmission electron microscopy (TEM). It was found that films annealed at temperatures below 850°C remained amorphous. Annealing at temperatures above 850°C resulted in the formation of SiC nanocrystallites, as revealed by GAXRD and TEM. The electrical conductivity also showed an abrupt increase around 950°C. Prolonged annealing resulted in a further increase in conductivity, implying that the transformation continued. Annealing at 1100°C for 3 hours increased the film conductivity by two orders of magnitude relative to the as-deposited film.

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