Fabrication and characterization of highly textured (Bi,Pb)2Sr2Ca2Cu3Ox superconducting ceramics using high magnetic field and cold isostatic pressing

1995 ◽  
Vol 10 (10) ◽  
pp. 2433-2443 ◽  
Author(s):  
Wai Lo ◽  
R. Stevens ◽  
R. Doyle ◽  
A.M. Campbell ◽  
W.Y. Liang
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Cold Isostatic Pressing ◽  
Sintered Ceramic ◽  
Grain Alignment ◽  
Isostatic Pressing ◽  
Transmission Electron ◽  
Superconducting Ceramics ◽  
High Degree

High textured (Bi,Pb)2Sr2Ca2Cu3Ox ceramics have been fabricated by aligning deflocculated flakes of (Bi,Pb)2Sr2Ca2Cu3Ox suspended in an organic medium by means of a high de magnetic field (6 T) at room temperature followed by cold isostatic pressing. The proportion of the (Bi,Pb)2Sr2Ca2Cu3Ox phase in the precursor powder was carefully controlled, and the characteristics of the powder, such as size distribution and morphology, were determined. A high degree of grain alignment was found in the specimens after the magnetic alignment, although the bulk density of the materials was low. Cold isostatic pressing substantially increased the density of the magnetically prealigned specimens which also resulted in a slight decrease in the degree of grain alignment. This minor realignment was found to be due to the various kinds of processing defects that appeared in the specimens during compaction due to the grinding and cracking of the grains and their interlocking. The microstructural and superconducting properties of the sintered ceramic have been studied using texture goniometry, high resolution scanning electron microscopy, transmission electron microscopy, ac magnetic susceptometry, and critical current measurements.

scholarly journals Structural characterization of Yba2Cu3O7–δ/Y2O3 composite films

1998 ◽  
Vol 13 (4) ◽  
pp. 954-958 ◽  
Author(s):  
P. R. Broussard ◽  
M. A. Wall ◽  
J. Talvacchio
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Coincidence Site Lattice ◽  
Composite Films ◽  
X Ray Diffraction ◽  
Plane Orientation ◽  
Transmission Electron ◽  
Two Phases ◽  
High Degree

Using 4-circle x-ray diffraction and transmission electron microscopy, we have studied the microstructure and in-plane orientation of the phases present in thin film composite mixtures of Yba2Cu3O7–δ and Y2O3. We see a high degree of in-plane orientation and have verified a previous prediction for the in-plane order of Y2BaCuO5 on (110) MgO. Transmission electron microscopy shows the composite films to be a mixture of two phases, with YBCO grain sizes of ≈1 μm. We have also compared our observations of the in-plane order to the predictions of a modified near coincidence site lattice model.

scholarly journals Characterization of graphene nanosheets obtained by a modified Hummer's method

2018 ◽  
Vol 23 (1) ◽  
Author(s):  
Renata Hack ◽  
Cláudia Hack Gumz Correia ◽  
Ricardo Antônio de Simone Zanon ◽  
Sérgio Henrique Pezzin
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Graphene Nanosheets ◽  
Scale Production ◽  
Natural Graphite ◽  
Graphite Oxidation ◽  
Transmission Electron ◽  
Large Scale Production ◽  
High Degree

ABSTRACT Natural graphite is an inexpensive and abundant source to obtain graphene nanosheets. The most efficient method for large-scale production is the chemical method, which is based on the oxidation of natural graphite. This paper reports the synthesis and characterization of graphene obtained by the Hummers method with some modifications. The results indicate a high degree of graphite oxidation, proving that the process was efficient. Analyses of field emission scanning electron microscopy (FEG), transmission electron microscopy (TEM), Raman spectroscopy, thermogravimetric analysis (TGA) and X-ray diffraction showed that the graphene produced presented characteristics similar to the commercial graphene.

Structural Characterization of Fe3O4–NiO Superlattices Using High-reSolution Transmission Electron Microscopy

1997 ◽  
Vol 12 (8) ◽  
pp. 2143-2151 ◽  
Author(s):  
A. Rečnik ◽  
D. L. Carroll ◽  
K. A. Shaw ◽  
D. M. Lind ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam ◽  
Spin Exchange ◽  
Magnetic Ordering ◽  
Misfit Dislocations ◽  
Transmission Electron ◽  
High Degree

Superlattices of Fe3O4–NiO layers have been studied by high-resolution transmission electron microscopy (HRTEM). These superlattices are grown by oxygen-plasma-assisted molecular-beam epitaxy (MBE) on (001) oriented MgO substrates, and exhibit a high degree of ordering at the interfaces between the interlayers. The lack of misfit dislocations at the Fe3O4–NiO interfaces suggeststhat lattice strain is largely accommodated by changes in the lattice spacing. By quantitative HRTEM analysis of Fe3O4–NiO interfaces, possible atomic models are discussed, having implications in magnetic ordering and spin exchange mechanisms for such interlayer systems.

scholarly journals Design and Characterization of Ag@Cu2O-rGO Nanocomposite for the p-Nitrophenol Reduction

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 43
Author(s):  
Chao Song ◽  
Shuang Guo ◽  
Lei Chen
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Catalytic Reduction ◽  
Catalytic Efficiency ◽  
Transmission Electron ◽  
Nitrophenol Reduction ◽  
Reduced Graphene ◽  
High Degree ◽  
Scanning Electron

In this paper, we designed Ag nanoparticles coated with a Cu2O shell, which was successfully decorated on reduced graphene oxide (rGO) via a solid-state self-reduction. The Cu2O, Ag@Cu2O, and Ag@Cu2O-rGO nanocomposites were synthesized and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis, and XPS to evaluate the properties of the composites. In order to compare the chemical catalytic activity, the Cu2O, Ag@Cu2O, and Ag@Cu2O-rGO nanocomposites were employed for the catalytic reduction of p-nitrophenol (4-NP) into p-aminophenol (4-AP) in aqueous solution. The Ag@Cu2O-rGO nanocomposite exhibited excellent catalytic activity due to the intense interaction and high degree of electron transfer among Ag, Cu2O, and rGO. The rGO acted as the platform to bridge the isolated nanoparticles; furthermore, the electrons could quickly transfer from the Ag core to the Cu2O shell, which improved the chemical catalytic efficiency.

Structural Characterization of Carbon Materials Prepared at Low Temperature

1995 ◽  
Vol 393 ◽  
Author(s):  
Xiang-Yun Song ◽  
Xi Chu ◽  
Kimio Kinoshita
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phenol Formaldehyde ◽  
High Capacity ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
High Degree

ABSTRACTHigh-capacity carbon electrodes for rechageable lithium-ion batteries were prepared by carbonization of thermosetting resins such as phenol-formaldehyde at temperatures between 500°C and 600°C. Their structures were characterized by high resolution transmission electron microscopy, in-situ transmission electron microscopy and x-ray diffraction analysis. These studies suggest that the carbons consist predominantly of disorganized (amorphous) phase. However evidence was found in carbon containing nickel cobalt oxide for the presence of organized graphite-like regions of parallel and curved layer planes. These graphitized structure usually appear as agglomerate particles which are composed of many smaller (100-nm diameter) particles. The high degree of graphitization is attributed to catalytic graphitization that occurs in the presence of the metal oxide.

Characterization of RF Sputtered ZnO Piezoelectric Films Using Transmission Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 86-87
Author(s):  
Kemining W. Yeh ◽  
Richard S. Muller ◽  
Wei-Kuo Wu ◽  
Jack Washburn
Keyword(s):  
Integrated Circuit ◽  
Acoustic Waves ◽  
New Technology ◽  
Surface Acoustic Waves ◽  
Electromechanical Properties ◽  
Leading Role ◽  
Saw Devices ◽  
Transmission Electron ◽  
High Degree

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.

Cryomicroscopy of multiphase latices

1991 ◽  
Vol 49 ◽  
pp. 1060-1061
Author(s):  
O. L. Shaffer ◽  
M.S. El-Aasser ◽  
C. L. Zhao ◽  
M. A. Winnik ◽  
R. R. Shivers
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Freeze Fracture ◽  
Particle Morphology ◽  
Second Stage ◽  
Transmission Electron ◽  
Important Approach ◽  
Carbon Coated ◽  
Preparation Techniques

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.

Applications of Transmission Electron Microscopy in the Characterization of Metal Machinability

1968 ◽  
Vol 26 ◽  
pp. 442-443 ◽  
Author(s):  
L.E. Murr ◽  
A.B. Draper
Keyword(s):  
Electron Microscopy ◽  
State Physics ◽  
Test Material ◽  
Milling Machine ◽  
Rotary Table ◽  
Solid State Physics ◽  
Materials Properties ◽  
Transmission Electron ◽  
Selection Of

The industrial characterization of the machinability of metals and alloys has always been a very arbitrarily defined property, subject to the selection of various reference or test materials; and the adoption of rather naive and misleading interpretations and standards. However, it seems reasonable to assume that with the present state of knowledge of materials properties, and the current theories of solid state physics, more basic guidelines for machinability characterization might be established on the basis of the residual machined microstructures. This approach was originally pursued by Draper; and our presentation here will simply reflect an exposition and extension of this research.The technique consists initially in the production of machined chips of a desired test material on a horizontal milling machine with the workpiece (specimen) mounted on a rotary table vice. A single cut of a specified depth is taken from the workpiece (0.25 in. wide) each at a new tool location.

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.

Characterization of submicrometer fluid Inclusions in minerals by Analytical/Transmission Electron Microscopy and electron diffraction

1990 ◽  
Vol 48 (4) ◽  
pp. 424-424
Author(s):  
George Guthrie ◽  
David Veblen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Light Microscopy ◽  
Fluid Inclusions ◽  
Energy Dispersive Spectrometer ◽  
Analytical Transmission Electron Microscopy ◽  
Transmission Electron

The nature of a geologic fluid can often be inferred from fluid-filled cavities (generally <100 μm in size) that are trapped during the growth of a mineral. A variety of techniques enables the fluids and daughter crystals (any solid precipitated from the trapped fluid) to be identified from cavities greater than a few micrometers. Many minerals, however, contain fluid inclusions smaller than a micrometer. Though inclusions this small are difficult or impossible to study by conventional techniques, they are ideally suited for study by analytical/ transmission electron microscopy (A/TEM) and electron diffraction. We have used this technique to study fluid inclusions and daughter crystals in diamond and feldspar.Inclusion-rich samples of diamond and feldspar were ion-thinned to electron transparency and examined with a Philips 420T electron microscope (120 keV) equipped with an EDAX beryllium-windowed energy dispersive spectrometer. Thin edges of the sample were perforated in areas that appeared in light microscopy to be populated densely with inclusions. In a few cases, the perforations were bound polygonal sides to which crystals (structurally and compositionally different from the host mineral) were attached (Figure 1).

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