Ordering With Phase Separation in an Fe-Al-Si Alloy

1983 ◽  
Vol 21 ◽  
Author(s):  
S. Matsumura ◽  
A. Sonobe ◽  
K. Oki ◽  
T. Eguchi
Keyword(s):  
Phase Separation ◽  
Early Stage ◽  
X Ray Diffraction ◽  
Modulated Structure ◽  
X Ray ◽  
Prolonged Annealing ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Degree Of Order ◽  
Phase Proceeds

ABSTRACTTwo kinds of process of ordering with phase separation, B2 or DO3 → (A2 + DO3), on annealing at a temperature of 873 K in an alloy of Fe-6 at%Al-9 at%Si were investigated by means of transmission electron microscopy and X-ray diffraction. The decomposition of DO3 phase proceeds by the development of periodic fluctuations along <100> directions in both B2 and DO3 types of degree of order. Newly born DO3 domains take the form of rectangular prism and align along <100> directions. In the transition from B2, on the contrary, there is a marked difference between the morphologies of the fluctuations in the two types of degree of order at the early stage of annealing. The degree of B2 type order fluctuates along <100> directions, while the fluctuation in the degree of DO3 type order does not form the <100> modulated structure sat the early stage of annealing. The morphology after a prolonged annealing is similar to that in the case of DO3 → (A2 + DO3).

Structural changes in titanium dioxide nanocrystals during plastic deformation

2005 ◽  
Vol 38 (5) ◽  
pp. 749-756 ◽  
Author(s):  
Ulrich Gesenhues
Keyword(s):  
Structural Changes ◽  
Crystal Size ◽  
Lower Layer ◽  
High Energy ◽  
Primary Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Hall Method ◽  
Means Of Transmission

The polygonization of 200 nm rutile crystals during dry ball-milling at 10gwas monitored in detail by means of transmission electron microscopy (TEM) and X-ray diffraction (XRD). The TEM results showed how to modify the Williamson–Hall method for a successful evaluation of crystal size and microstrain from XRD profiles. Macrostrain development was determined from the minute shift of the most intense reflection. In addition, changes in pycnometrical density were monitored. Accordingly, the primary crystal is disintegrated during milling into a mosaic of 12–35 nm pieces where the grain boundaries induce up to 1.2% microstrain in a lower layer of 6 nm thickness. Macrostrain in the interior of the crystals rises to 0.03%. The pycnometrical density, reflecting the packing density of atoms in the grain boundary, decreases steadily by 1.1%. The results bear relevance to our understanding of plastic flow and the mechanism of phase transitions of metal oxides during high-energy milling.

TEM Analysis on Bio-Functional Gradient Hydroxyapatite/ZrO2 Coatings

2007 ◽  
Vol 336-338 ◽  
pp. 1676-1678
Author(s):  
Cheng Yun Ning ◽  
Ying Jun Wang ◽  
Xiao Feng Chen ◽  
Jian Dong Ye ◽  
Gang Wu ◽  
...  
Keyword(s):  
Net Energy ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
X Ray ◽  
Amorphous Phases ◽  
Functional Gradient ◽  
Transmission Electron ◽  
Gradient Coatings ◽  
Means Of Transmission ◽  
Sprayed Coatings

In the present study, bioactive functional gradient coatings were prepared using net-energy controlled plasma spraying technology. The microstructure and phases of the bioactive functional gradient coating were examined by means of transmission electron microscope, scanning electron microscopy and X-ray diffraction. The results revealed that: (1) as-sprayed coatings contained a large amount of amorphous phases and some nano-sized HA crystals formed during rapid solidification, (2) surface of the coating was very rough with different-sized micropores, and the gradient layer was much denser which firmly bonded to the substrate without gaps and obvious interface between the coating and the substrate

Cross-Sectional TEM Study Of Phase Separation In Reaction Of Ni-Ta Films With GaAs

1985 ◽  
Vol 54 ◽  
Author(s):  
A. Lahav ◽  
M. Eizenberg ◽  
Y. Komem
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
Phase Separation ◽  
Gaas Substrate ◽  
Auger Spectroscopy ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron

ABSTRACTThe reaction between Ni60Ta40 amorphous alloy and (001) GaAs was studied by cross-sectional transmission electron microscopy, Auger spectroscopy, and x-ray diffraction. At 400°C formation of Ni GaAs at the interface with GaAs was observed. After heat treatment at 600°C in vacuum a layered structure of TaAs/NiGa/GaAs has been formed. The NiGa layer has epitaxial relations to the GaAs substrate. The vertical phase separation can be explained by opposite diffusion directions of nickel and arsenic atoms.

Detection and Analysis of Phase Separation in Metalorganic Chemical Vapor Deposition InGaN

1997 ◽  
Vol 482 ◽  
Author(s):  
E. L. Piner ◽  
N. A. El-Masry ◽  
S. X. Liu ◽  
S. M. Bedair
Keyword(s):  
Chemical Vapor Deposition ◽  
Phase Separation ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Single Phase ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Metalorganic Chemical

AbstractInGaN films in the 0–50% InN composition range have been analyzed for the occurrence of phase separation. The ñ0.5 jum thick InGaN films were grown by metalorganic chemical vapor deposition (MOCVD) in the 690 to 780°C temperature range and analyzed by θ−20 x-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area diffraction (SAD). As-grown films with up to 21% InN were single phase. However, for films with 28% InN and higher, the samples showed a spinodally decomposed microstructure as confirmed by TEM and extra spots in SAD patterns that corresponded to multiphase InGaN. An explanation of the data based on the GaN-InN pseudo-binary phase diagram is discussed.

scholarly journals Silicon Carbide-Derived Carbon Prepared by Fused Salt Electrolysis and Electrochemical Performance

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Shuyuan Wang ◽  
Guangjie Shao
Keyword(s):  
Electrochemical Performances ◽  
Constant Voltage ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Carbide Derived Carbon ◽  
Degree Of Order ◽  
A Current

A number of carbide-derived carbon (CDC) samples were successfully synthesized by the electrolysis of SiC powder in molten CaCl2. The electrolysis was conducted at different temperatures (850, 900, and 950°C) for 48 h in argon at an applied constant voltage of 3.1 V. The structure of the resulting carbon is characterized by X-ray diffraction, Raman spectroscopy, and transmission electron microscope techniques. Cyclic voltammetry and galvanostatic charge/discharge measurements are applied to investigate electrochemical performances of the SiC-CDC material. It can be seen that the degree of order of the SiC-CDC increases monotonically along with elevation of reaction temperature, while the highest specific surface area 1137.74 m2/g together with a specific capacitance of 161.27 F/g at a current density 300 mA/g was achieved from sample synthesized at 900°C.

scholarly journals Investigation of magnetite Fe3O4 nanoparticles for magnetic hyperthermia

Nukleonika ◽  
2017 ◽  
Vol 62 (2) ◽  
pp. 183-186 ◽  
Author(s):  
Zbigniew Surowiec ◽  
Arkadiusz Miaskowski ◽  
Mieczysław Budzyński
Keyword(s):  
Room Temperature ◽  
Magnetic Hyperthermia ◽  
Size Distributions ◽  
Heating Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
Relative Contribution ◽  
Transmission Electron ◽  
Magnetite Fe3o4 ◽  
Means Of Transmission

Abstract The paper presents the investigation of magnetic nanoparticles (MNPs) dedicated to hyperthermia application. The crystal structure and size distributions have been determined by means of transmission electron microscope (TEM) and X-ray diffraction (XRD). Magnetic properties of the nanoparticles were tested by Mössbauer spectroscopy together with calorimetric experiments. The Mössbauer spectroscopic study of MNPs revealed the existence of a superparamagnetic phase. The relative contribution of the relaxing component to the total spectrum at room temperature was about 10%. The heating effect of these MNPs under alternating magnetic field was examined. The temperature increase has reached 5°C in 10 min. The preliminary temperature rise suggests that the investigated materials are applicable for hyperthermia.

scholarly journals Luminescence Nanothermometry Based on Pr3+ : LaF3 Single Core and Pr3+ : LaF3/LaF3 Core/Shell Nanoparticles

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
M. S. Pudovkin ◽  
D. A. Koryakovtseva ◽  
E. V. Lukinova ◽  
S. L. Korableva ◽  
R. Sh. Khusnutdinova ◽  
...  
Keyword(s):  
Coherent Scattering ◽  
Core Shell ◽  
Fluorescence Intensity Ratio ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Core Shell Nanoparticles

Core Pr3+ : LaF3 (CPr = 1%) plate-like nanoparticles (nanoplates), core/shell Pr3+ : LaF3 (CPr = 1%)/LaF3 nanoplates, core Pr3+ : LaF3 (CPr = 1%) sphere-like nanoparticles (nanospheres), and core/shell Pr3+ : LaF3 (CPr = 1%)/LaF3 nanospheres were synthesized via the coprecipitation method of synthesis. The nanoparticles (NPs) were characterized by means of transmission electron microscopy, X-ray diffraction, and optical spectroscopy. The formation of the shell was proved by detecting the increase in physical sizes, sizes of coherent scattering regions, and luminescence lifetimes of core/shell NPs comparing with single core NPs. The average physical sizes of core nanoplates, core/shell nanoplates, core nanospheres, and core/shell nanospheres were 62.2 ± 0.9, 74.7 ± 1.2, 13.8 ± 0.9 and 22.0 ± 1.2 nm, respectively. The formation of the NP shell led to increasing of effective luminescence lifetime τeff of the 3P0 state of Pr3+ ions for the core nanoplates, core/shell nanoplates, core nanospheres, and core/shell nanospheres the values of τeff were 2.3, 3.6, 3.2, and 4.7 μsec, respectively (at 300 K). The values of absolute sensitivity Sa for fluorescence intensity ratio (FIR) thermometry was 0.01 K−1 at 300 K for all the samples. The FIR sensitivity can be attributed to the fact that 3P1 and 3P0 states share their electronic populations according to the Boltzmann process. The values of Sa for lifetime thermometry for core nanoplates, core/shell nanoplates, core nanospheres, and core/shell nanospheres were (36.4 ± 3.1) · 10−4, (70.7 ± 5.9) · 10−4, (40.7 ± 2.6) · 10−4, and (68.8 ± 2.4) · 10−4 K−1, respectively.

Partial cation-order and early-stage, phase separation in phase W, Li x Co 1− x O: 0.075≤ x ≤0.24−0.31

2009 ◽  
Vol 465 (2106) ◽  
pp. 1829-1841 ◽  
Author(s):  
Y. Wu ◽  
D. Pasero ◽  
E.E. McCabe ◽  
Y. Matsushima ◽  
A.R. West
Keyword(s):  
Phase Separation ◽  
Early Stage ◽  
Domain Size ◽  
Solid Solution Phase ◽  
X Ray ◽  
Cation Order ◽  
Transmission Electron ◽  
X Ray Absorption ◽  
Li Content ◽  
Disordered Regions

We report the characterization using X-ray and neutron powder diffraction, transmission electron microscopy and extended X-ray absorption fine structure of a new, partially ordered rock-salt-like solid solution phase Li x Co 1− x O: 0.075≤ x ≤0.24−0.31. The cation stacking sequence along [111] consists of alternating planes of Co and Co/Li. Nano-sized domains of this cation-ordered phase appear alongside disordered regions; domain size increases from 2 to 8 nm with increasing Li content. Compositions of ordered and disordered regions are Li- and Co-rich, respectively, and, therefore, the phase exhibits frozen-in, incipient phase separation. This microstructure could be considered as a precursor to precipitation of fully ordered, rhombohedral LiCoO 2 .

Synthesis of CdWO4 Nanoflakes and Nanorods by a Sonochemical Process

2012 ◽  
Vol 174-177 ◽  
pp. 413-416
Author(s):  
Jin Liu ◽  
Lin Lin Yang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Early Stage ◽  
Ultrasound Irradiation ◽  
Sonochemical Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Ultrasonic Time ◽  
Template Free

CdWO4 nanoflakes and nanorods have been successfully prepared through a mild template-free sonochemical method without any surfactants. The as-prepared samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that the ultrasound irradiation played an important role in the formation of CdWO4 crystals. The results showed that CdWO4 nanoflakes were first formed at the early stage, and CdWO4 nanoflakes were transformed into nanorods as the ultrasonic time was prolonged from 0.5h to 1.5h.

scholarly journals Sensitivity of Mesoporous CoSb2O6Nanoparticles to Gaseous CO and C3H8at Low Temperatures

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Héctor Guillén-Bonilla ◽  
Lorenzo Gildo-Ortiz ◽  
M. de la L. Olvera-Amador ◽  
Jaime Santoyo-Salazar ◽  
Verónica M. Rodríguez-Betancourtt ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensors ◽  
Low Temperatures ◽  
Cobalt Nitrate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Precursor Material ◽  
Means Of Transmission ◽  
Average Size

Mesoporous CoSb2O6nanoparticles, synthesized through a nonaqueous method (using cobalt nitrate, antimony trichloride, ethylenediamine, and ethanol as a solvent), were tested to establish their sensitivity to CO and C3H8atmospheres at relatively low temperatures. The precursor material was dried at 200°C and calcined at 600°C. X-ray diffraction and scanning electron microscopy were employed to verify the existence of crystal phases (P42/mnm) and the morphology of this trirutile-type CoSb2O6oxide. Pyramidal and cubic shaped crystals (average size: 41.1 nm), embedded in the material’s surface, were identified. Mesopores (average size: 6.5 nm) on the nanoparticles’ surface were observed by means of transmission electron microscopy. The best sensitivity of the CoSb2O6in a CO atmosphere was at the relatively low temperatures of 250 and 350°C, whereas, in a C3H8atmosphere, the sensitivity increased uniformly with temperature. These results encourage using the CoSb2O6nanoparticles as gas sensors.

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