scholarly journals Ориентационные соотношения при структурном превращении моноклинной и кубической фаз в сульфиде серебра

2019 ◽  
Vol 53 (7) ◽  
pp. 958
Author(s):  
С.И. Садовников ◽  
А.А. Ремпель
Keyword(s):  
High Temperature ◽  
Nonvolatile Memory ◽  
Silver Sulfide ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
Transmission Electron ◽  
Nonvolatile Memory Devices ◽  
Metal Sublattice ◽  
Resistive Switches ◽  
Potential Basis

Based on the experimental data on high-temperature X-ray diffraction and high resolution transmission electron microscopy of silver sulfide, the orientation relationships between the low-temperature monoclinic semiconductor acantite alfa-Ag2S and the high-temperature body-centered argentite beta-Ag2S are determined. It is found that, in contrast to acanthite, the possible distances between silver atoms in a cubic argentite are too small for the positions of the metal sublattice to be occupied by Ag atoms with a probability of 1. It is shown that the acanthite (010) and (001) atomic planes are parallel to the planes ( 1-10) and (221) of argentite, respectively. The orientational relationships found between acanthite and argentite are important for understanding the physical action of the Ag2S/Ag heteronanostructure, considered as a potential basis for creating resistive switches and nonvolatile memory devices.

Effect of the Pulse Laser Radiation on the Stabilization of the ZrO2 and HFO2 High-Temperature Phases

2015 ◽  
Vol 245 ◽  
pp. 200-203 ◽  
Author(s):  
Maxim Alexandrovich Pugachevskii ◽  
Viktor Igorevich Panfilov
Keyword(s):  
High Temperature ◽  
Transmission Electron Microscopy Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Quantitative Content ◽  
Electron Microscopy Data ◽  
Cubic Phases ◽  
Transmission Electron ◽  
Microscopy Data

The conditions of formation of the ZrO2 and HfO2 high-temperature (tetragonal and cubic) phases in the ablated nanoparticles were investigated. X-ray diffraction and transmission electron microscopy data demonstrate that laser intensities above 109 W/m2 ensure the formation of the ZrO2 high-temperature phases, while intensities above 5·109 W/m2 do the formation of the HfO2 high-temperature phases. Quantitative content of the high-temperature phases in layers of the ablated nanoparticles increases with raising the intensity. The obtained nanoparticles exhibit good thermal stability.

Microstructures of two-phase Ti–Cr alloys containing the TiCr2 Laves phase intermetallic

1997 ◽  
Vol 12 (6) ◽  
pp. 1472-1480 ◽  
Author(s):  
Katherine C. Chen ◽  
Samuel M. Allen ◽  
James D. Livingston
Keyword(s):  
Laves Phase ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
Phase Growth ◽  
Two Phase ◽  
X Ray ◽  
Lattice Constants ◽  
Annealing Temperatures ◽  
Transmission Electron ◽  
Phase Intermetallic

Microstructures of two-phase Ti–Cr alloys (Ti-rich bcc + TiCr2 and Cr-rich bcc + TiCr2) are analyzed. A variety of TiCr2 precipitate morphologies is encountered with different nominal alloy compositions and annealing temperatures. Lattice constants and crystal structures are determined by x-ray diffraction (XRD) and transmission electron microscopy (TEM). Orientation relationships between the beta bcc solid solution and C15 TiCr2 Laves phase are understood in terms of geometrical packing, and are consistent with a Laves phase growth mechanism involving twinning.

Characterization of the Phase Transformations in the Shape Memory Alloy Ni-36 at.% Al

1991 ◽  
Vol 246 ◽  
Author(s):  
J.A. Horton ◽  
E.P. George ◽  
C.J. Sparks ◽  
M.Y. Kao ◽  
O.B. Cavin ◽  
...  
Keyword(s):  
High Temperature ◽  
Shape Memory ◽  
Phase Transformations ◽  
Hot Extrusion ◽  
Exothermic Peak ◽  
Nickel Aluminum ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron

AbstractA survey by differential scanning calorimetry (DSC) and recovery during heating of indentations on a series of nickel-aluminum alloys showed that the Ni-36 at.% Al composition has the best potential for a recoverable shape memory effect at temperatures above 100°C. The phase transformations were studied by high temperature transmission electron microscopy (TEM) and by high temperature x-ray diffraction (HTXRD). Quenching from 1200°C resulted in a single phase, fully martensitic structure. The initial quenched-in martensites were found by both TEM and X-ray diffraction to consist of primarily a body centered tetragonal (bct) phase with some body centered orthorhombic (bco) phase present. On the first heating cycle, DSC showed an endothermic peak at 121°C and an exothermic peak at 289°C, and upon cooling a martensite exothermic peak at 115° C. Upon subsequent cycles the 289°C peak disappeared. High temperature X-ray diffraction, with a heating rate of 2°C/min, showed the expected transformation of bct phase to B2 between 100 and 200°C, however the bco phase remained intact. At 400 to 450°C the B2 phase transformed to Ni2Al and Ni5Al3. During TEM heating experiments a dislocation-free martensite transformed reversibly to B2 at temperatures less than 150°C. At higher temperatures (nearly 600°C) 1/3, 1/3, 1/3 reflections from an ω-like phase formed. Upon cooling, the 1/3, 1/3, 1/3 reflections disappeared and a more complicated martensite resulted. Boron additions suppressed intergranular fracture and, as expected, resulted in no ductility improvements. Boron additions and/or hot extrusion encouraged the formation of a superordered bct structure with 1/2, 1/2, 0 reflections.

Epitaxial Pd-Doped LaFeO3 Films Grown on (100) SrTiO3 by Pulsed Laser Deposition

2014 ◽  
Vol 936 ◽  
pp. 282-286
Author(s):  
Ying Wen Duan
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Film Surface ◽  
Laser Deposition ◽  
Structural Quality ◽  
Deposition Technique ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
X Ray ◽  
Transmission Electron

Single-crystalline, epitaxial LaFeO3 films with 5 at. % substitution of Pd on the Fe site are grown on (100) SrTiO3 substrate by pulsed-laser deposition technique. The epitaxial orientation relationships are (110)[001]LFPO||(100)[001]STO. X-ray diffraction and transmission electron microscopy reveal that the LFPO films have high structural quality and an atomically sharp LFPO/STO interface. After reduction treatments of as-grown LFPO films, very little Pd escaped the LFPO lattice onto the film surface, the formed Pd (100) particles are oriented epitaxially, and parallel to the LFPO films surface.

scholarly journals A novel and facile method for silica nanoparticles synthesis from high temperature vulcanization (HTV) silicon

10.30544/134 ◽  
2016 ◽  
Vol 22 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Mohammad Senemar ◽  
Ali Maleki ◽  
Behzad Niroumand ◽  
Alireza Allafchian
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Silica Nanoparticles ◽  
Amorphous Silica ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Nanoparticles Synthesis ◽  
Novel Method ◽  
Scanning Electron

This study is introducing a facile and novel method for synthesis of amorphous silica nanoparticles. Silica nanoparticles were synthesized by pyrolysis and combustion of high temperature vulcanization (HTV) silicone at 700 oC for 1 h. The products were investigated employing transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), X-ray diffraction (XRD), Brunauer Emmett and Teller (BET) test and Fourier Transform Infrared (FTIR) Spectroscopy. The results indicated that the method is capable of synthesis of amorphous silica nanoparticles with sizes of mostly between 10 and 50 nm.

500℃ high-temperature reliability of Ni/Nb Ohmic contact on n-type 4H-SiC

2021 ◽  
Author(s):  
Vuong Van Cuong ◽  
Tadashi Sato ◽  
Takamichi Miyazaki ◽  
Tetsuya Meguro ◽  
Seiji Ishikawa ◽  
...  
Keyword(s):  
High Temperature ◽  
Ohmic Contact ◽  
Chemical Compounds ◽  
Etching Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ohmic Behavior ◽  
Transmission Electron ◽  
Current Voltage ◽  
The Stability

Abstract The reliability of Ni/Nb ohmic contact on n-type 4H-SiC at 500℃ was investigated. The current-voltage characteristics showed that, while the Ni(50)/Nb(50)/4H-SiC sample without applying the CF4:O2 etching process degraded just after 25-hour and lost ohmic behavior after 50-hour aging, the Ni(75)/Nb(25)/4H-SiC contact undergone CF4:O2 surface treatment still showed excellent stability after aging for 100 hours at 500℃. Though X-ray diffraction results indicated that the chemical compounds remained stable during the aging process, transmission electron microscopy showed that there was a redistribution of the chemical compounds at the interface of the contact after 500℃ aging. The depth distribution of the elements and energy dispersive X-ray analyses revealed that the contribution of carbon agglomeration at the interface accounted for the degradation of the sample without applying the etching process. Whereas the well-controlled excess carbon atoms of the contact undergone CF4:O2 treatment ensured the stability of this contact when operating at high-temperature ambient.

The Investigation of Structural and Magnetic Properties at High-Temperature of Nanostructured Fe90-Mg10 Alloys Produced by Mechanical Alloying

2018 ◽  
Vol 54 ◽  
pp. 136-145
Author(s):  
A. El Mohri ◽  
M. Zergoug ◽  
K. Taibi ◽  
M. Azzaz
Keyword(s):  
High Temperature ◽  
Mechanical Alloying ◽  
Milling Time ◽  
High Energy ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
The Mean

Nanocrystalline Fe90Mg10 alloy samples were prepared by mechanical alloying process using planetary high energy ball mill. The prepared powders were characterized using differential thermal analysis (DTA), X-ray diffraction technique (XRD) at high temperature, transmission electron microscopy (TEM), and the vibrating sample magnetometer (VSM). Obtained results are discussed according to milling time. XRD at high temperature results also indicated that when the milling time increases, the lattice parameter and the mean level of grain size increase, whereas the microstrains decrease. The result of the observation by the TEM of the Fe-Mg powders prepared in different milling time, coercive fields derived and Saturation magnetization derived from the hysteresis curves in high temperature are discussed as a function of milling time.

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