Characterization of Reactively Sputtered Titanium Carbide Films by Analytical Electron Microscopy

1985 ◽  
Vol 62 ◽  
Author(s):  
J. Tafto ◽  
G. Rajeswaran ◽  
T. Saulys
Keyword(s):  
Electron Microscopy ◽  
Core Loss ◽  
Analytical Electron Microscopy ◽  
Face Centered Cubic ◽  
Transmission Electron ◽  
Partial Pressures ◽  
The Face ◽  
Face Centered ◽  
Electron Energy Loss

ABSTRACTTICx films prepared by reactive sputtering using a Ti target and different methane partial pressures were characterized by analytical transmission electron microscopy. The films are polycrystalline, and the plasmon energy increases considerably with increasing carbon content. Combination of the information obtained from electron energy loss plasmon and core loss spectra, and electron diffraction indicates that x in TiCx increases linearly with methane partial pressure. We find that the face centered cubic TIC phase spans the composition from TiC0.2 to TiC1.0 and when x<l we have a mixture of TiC1.0 and amorphous C.

Transmission Electron Microscopy Studies of the Nanoscale Structure and Chemistry of Pt50Ru50 Electrocatalysts

2002 ◽  
Vol 8 (1) ◽  
pp. 50-57 ◽  
Author(s):  
Rhonda M. Stroud ◽  
Jeffrey W. Long ◽  
Karen E. Swider-Lyons ◽  
Debra R. Rolison
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Face Centered Cubic ◽  
Oxidation Activity ◽  
Transmission Electron ◽  
Diffraction Lattice ◽  
Nanoscale Structure ◽  
Face Centered ◽  
Electron Energy Loss ◽  
Lower Oxidation

The structural and chemical heterogeneity of 2.5-nm Pt50Ru50 electrocatalysts was studied by transmission electron microscopy using selected area diffraction, lattice imaging, electron-energy loss spectroscopy, and energy-dispersive X-ray spectroscopy. The catalysts with the highest methanol oxidation activities exhibit oxidation-induced phase separation on the nanoscale to form Pt-rich metal embedded in Ru-rich hydrous and anhydrous oxide. Reduction of the oxide-on-metal samples produces a true bimetallic face-centered cubic Pt50Ru50 alloy, with 275 times lower oxidation activity.

scholarly journals A Sequence of Phase Transformations and Phases in NiCoFeCrGa High Entropy Alloy

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1076
Author(s):  
Ádám Vida ◽  
János Lábár ◽  
Zoltán Dankházi ◽  
Zsolt Maksa ◽  
Dávid Molnár ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Phase Transitions ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
High Entropy ◽  
Transmission Electron ◽  
Temperature Ranges ◽  
Face Centered ◽  
Electron Energy Loss

The present investigation is directed to phase transitions in the equimolar NiCoFeCrGa high entropy alloy, which is a mixture of face-centered cubic (FCC) and body-centered cubic (BCC) crystalline phases. The microstructure of the samples was investigated by using scanning electron microscopy (SEM), time-of-flight secondary ion mass spectroscopy (TOF-SIMS), transmission electron microscopy-based energy-dispersive spectroscopy (EDS) and electron energy loss spectroscopy (EELS), as well as X-ray diffraction (XRD) measurements. Based on the phases observed in different temperature ranges, a sequence of the phase transitions can be established, showing that in a realistic process, when freely cooling the sample with the furnace from high to room temperature, a microstructure having spinodal-like decomposition can also be expected. The elemental mapping and magnetic behaviors of this decomposed structure are also studied.

scholarly journals Characterization of crystal structure and precipitation crystallography of a new MgxAl2−xGd phase in an Mg97Al1Gd2alloy

2016 ◽  
Vol 49 (4) ◽  
pp. 1177-1181 ◽  
Author(s):  
X.-F. Gu ◽  
T. Furuhara
Keyword(s):  
Crystal Structure ◽  
Lattice Parameter ◽  
Face Centered Cubic ◽  
Laves Phases ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Matrix ◽  
The Face ◽  
Face Centered

The composition, crystal structure and precipitation crystallography of a newly found precipitate are characterized by Cs-corrected scanning transmission electron microscopy. The composition of the plate-like precipitate could be expressed as MgxAl2−xGd (x= 0.38), and its crystal structure is the same as the face-centered cubic type Laves phases Mg2Gd and Al2Gd, with a lattice parameter of 7.92 Å (space group No. 227, Fd\overline 3m). The orientation relationship between the matrix and precipitate is found to be (0001)m//(111)pand [10\overline 10]m//[1\overline 10]p, and the habit plane is parallel to the (0001)m//(111)pplane. In addition, this preferred crystallography of phase transformation is well explained on the basis of the atomic matching at the interface.

Characterization of (Bi, Pb)-Sr-Ca-Cu-O system by analytical electron microscopy

1990 ◽  
Vol 5 (4) ◽  
pp. 737-741 ◽  
Author(s):  
Yasuhide Inoue ◽  
Masahiro Hasegawa ◽  
Yushi Shichi ◽  
Fumio Munakata ◽  
Mitsugu Yamanaka ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Microprobe Analysis ◽  
Analytical Electron Microscopy ◽  
Solid State Reaction Method ◽  
Chemical Compositions ◽  
Transmission Electron ◽  
Partial Pressures ◽  
Analytical Electron ◽  
Substitution Ratio

Chemical compositions of superconductors of Bi1−xPbxSrCaCu1.8Oy (x = 0.1, 0.3, and 0.5) were investigated by analytical electron microscopy (AEM) supplemented by electron microprobe analysis. Samples were prepared by a solid state reaction method under oxygen partial pressures of 0.20 and 0.077 atm. The high-Tc phase appeared only in the samples of Bi1−xPbxSrCaCu1.8Oy (x = 0.1 and 0.3) prepared under an oxygen partial pressure of 0.077 atm. In the samples containing the high-Tc phase, stacking structures of 2, 3, and 4 perovskite layers were observed by transmission electron microscopy (TEM). From AEM analysis, it was shown that in order to make the high-Tc phase, the substitution ratio of Pb for Bi was about 0.2.

Interface structures in polycrystalline ceramic materials

1986 ◽  
Vol 44 ◽  
pp. 468-471
Author(s):  
K. J. Morrissey
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Physical And Mechanical Properties ◽  
High Resolution Electron Microscopy ◽  
Ceramic Materials ◽  
Polycrystalline Materials ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Interface Structures

Grain boundaries and interfaces play an important role in determining both physical and mechanical properties of polycrystalline materials. To understand how the structure of interfaces can be controlled to optimize properties, it is necessary to understand and be able to predict their crystal chemistry. Transmission electron microscopy (TEM), analytical electron microscopy (AEM,), and high resolution electron microscopy (HREM) are essential tools for the characterization of the different types of interfaces which exist in ceramic systems. The purpose of this paper is to illustrate some specific areas in which understanding interface structure is important. Interfaces in sintered bodies, materials produced through phase transformation and electronic packaging are discussed.

scholarly journals The Examination of Calcium ion Implanted Alumina with Energy Filtered Transmission Electron Microscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 413-414
Author(s):  
E.M. Hunt ◽  
J.M. Hampikian ◽  
N.D. Evans
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Pure Aluminum ◽  
Lattice Parameter ◽  
Face Centered Cubic ◽  
Ion Channeling ◽  
Transmission Electron ◽  
Knoop Microhardness ◽  
Aluminum Nanocrystals ◽  
Face Centered

Ion implantation can be used to alter the optical response of insulators through the formation of embedded nano-sized particles. Single crystal alumina has been implanted at ambient temperature with 50 keV Ca+ to a fluence of 5 x 1016 ions/cm2. Ion channeling, Knoop microhardness measurements, and transmission electron microscopy (TEM) indicate that the alumina surface layer was amorphized by the implant. TEM also revealed nano-sized crystals ≈7 - 8 nm in diameter as seen in Figure 1. These nanocrystals are randomly oriented, and exhibit a face-centered cubic structure (FCC) with a lattice parameter of 0.409 nm ± 0.002 nm. The similarity between this crystallography and that of pure aluminum (which is FCC with a lattice parameter of 0.404 nm) suggests that they are metallic aluminum nanocrystals with a slightly dilated lattice parameter, possibly due to the incorporation of a small amount of calcium.Energy-filtered transmission electron microscopy (EFTEM) provides an avenue by which to confirm the metallic nature of the aluminum involved in the nanocrystals.

Structural characterization of SmMn2GeO7 single microcrystals by electron microscopy

2005 ◽  
Vol 61 (1) ◽  
pp. 11-16 ◽  
Author(s):  
E. A. Juarez-Arellano ◽  
J. M. Ochoa ◽  
L. Bucio ◽  
J. Reyes-Gasga ◽  
E. Orozco
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Characterization ◽  
Point Group ◽  
Spherical Mirror ◽  
Quaternary Compound ◽  
Cell Parameters ◽  
Transmission Electron ◽  
Electron Energy Loss

Single microcrystals of the new compound samarium dimanganese germanium oxide, SmMn2GeO7, were grown using the flux method in a double spherical mirror furnace (DSMF). The micrometric crystals were observed and chemically analysed with scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDX). The structural characterization and chemical analysis of these crystals were also carried out using transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), together with electron-energy-loss spectroscopy (EELS). We found that the new quaternary compound crystallizes in the orthorhombic system with the point group mmm (D 2h ), space group Immm (No. 71) and cell parameters a = 8.30 (10), b = 8.18 (10), c = 8.22 (10) Å and V = 558.76 Å3.

Structural, morphological, and magnetic study of nanocrystalline cobalt-copper powders synthesized by the polyol process

1995 ◽  
Vol 10 (6) ◽  
pp. 1546-1554 ◽  
Author(s):  
G.M. Chow ◽  
L.K. Kurihara ◽  
K.M. Kemner ◽  
P.E. Schoen ◽  
W.T. Elam ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Copper Powders ◽  
Face Centered ◽  
Increasing Temperature ◽  
X Ray Absorption

Nanocrystalline CoxCu100−x (4 ⋚ x ⋚ 49 at. %) powders were prepared by the reduction of metal acetates in a polyol. The structure of powders was characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), extended x-ray absorption fine structure (EXAFS) spectroscopy, solid-state nuclear magnetic resonance (NMR) spectroscopy, and vibrating sample magnetometry (VSM). As-synthesized powders were composites consisting of nanoscale crystallites of face-centered cubic (fcc) Cu and metastable face-centered cubic (fcc) Co. Complementary results of XRD, HRTEM, EXAFS, NMR, and VSM confirmed that there was no metastable alloying between Co and Cu. The NMR data also revealed that there was some hexagonal-closed-packed (hcp) Co in the samples. The powders were agglomerated, and consisted of aggregates of nanoscale crystallites of Co and Cu. Upon annealing, the powders with low Co contents showed an increase in both saturation magnetization and coercivity with increasing temperature. The results suggested that during preparation the nucleation of Cu occurred first, and the Cu crystallites served as nuclei for the formation of Co.

Photocatalytic Analysis and Characterization of Zn2SnO4 Nanoparticles Synthesized via Hydrothermal Method with Na2CO3 Mineralizer

2010 ◽  
Vol 97-101 ◽  
pp. 19-22 ◽  
Author(s):  
Yu Shiang Wu ◽  
Wen Ku Chang ◽  
Min Jou
Keyword(s):  
Photocatalytic Activity ◽  
Hydrothermal Process ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
Transmission Electron ◽  
Excellent Photocatalytic Activity ◽  
Face Centered ◽  
Xrd Patterns

Zinc stannate Zn2SnO4 (ZTO) nanoparticles were synthesized via a hydrothermal process utilizing sodium carbonate (Na2CO3) as a weak basic mineralizer. The samples were hydrothermally treated at 150, 200, and 250oC for 48 h. The X-ray diffraction (XRD) patterns show that the highly-crystalline ZTO nanostructure could be formed in a well-dispersed manner for the 250°C sample at a particle size of less than 50 nm. As determined from transmission electron microscopy (TEM) results, ZTO nanoparticles are face-centered cubic single crystals agglomerated together. The Raman spectra results showed that the ZTO nanocrystals have a spinel structure. Furthermore, photocatalytic activity was tested with methylene blue (MB) by UV irradiation. The ZTO synthesized by the 2 M Na2CO3 mineralizer at 250oC demonstrated excellent photocatalytic activity. The ZTO treated three different ways had three distinct UV-Visible absorption curves, which directly influences their corresponding photocatalytic activity.

Sign in / Sign up

Export Citation Format

Share Document