A Tem Study of Inverse Melting in Nb45Cr55

1995 ◽  
Vol 398 ◽  
Author(s):  
W. Sinkler ◽  
C. Michaelsen ◽  
R. Bormann
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Grain Boundaries ◽  
Amorphous Phase ◽  
Transmission Electron ◽  
High Resolution Tem

ABSTRACTInverse melting of bcc Nb4sCr55 is investigated using transmission electron microscopy, high-resolution TEM and electron diffraction. It is shown that the transformation to the amorphous phase initiates at the bcc grain boundaries. The transformation results in an increase in incoherence, evidenced by a loss of bend contours. Some anisotropy is found in the amorphous phase produced by inverse melting, which is associated in HRTEM with preferentially oriented but discontinuous and distorted fringes. The results are consistent with the production of an amorphous phase by inverse melting.

scholarly journals Transmission electron microscopy as an important tool for characterization of zeolite structures

2018 ◽  
Vol 5 (11) ◽  
pp. 2836-2855 ◽  
Author(s):  
W. Wan ◽  
J. Su ◽  
X. D. Zou ◽  
T. Willhammar
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Electron Tomography ◽  
Structure Characterization ◽  
Transmission Electron ◽  
High Resolution Tem

This review presents various TEM techniques including electron diffraction, high-resolution TEM and scanning TEM imaging, and electron tomography and their applications for structure characterization of zeolite materials.

Analysis of Nanocrystal of Porous Silicon with High-Resolution Transmission Electron Microscopy

2013 ◽  
Vol 650 ◽  
pp. 34-38 ◽  
Author(s):  
Jing Mei Lu ◽  
Xuan Cheng
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Porous Silicon ◽  
Electron Diffraction ◽  
Grain Boundaries ◽  
Crystal Plane ◽  
Electrochemical Polarization ◽  
Transmission Electron

The porous silicon samples were prepared with n(111) Si wafers by electrochemical polarization and their microstructures were characterized by high-resolution transmission electron microscopy (HRTEM). The DigitalMicrograph image processing was used to analyze the HRTEM images. The distorted Si (111) crystal plane was observed on porous silicon and could be distinguished with the Fourier transforming electron diffraction (ED) pattern. Grain boundaries were presented in the HRTEM images where the lattice fringes distortions took place. The anisotropy property could be preserved at a small location area because of the smaller nanocrystals in different directions appeared amorphous in the ED pattern at a larger range.

A Study of the Origin of Band-A Emission in Homoepitaxial Diamond Thin Films

1999 ◽  
Vol 588 ◽  
Author(s):  
Daisuke Takeuchi ◽  
Hideyuki Watanabe ◽  
Sadanori Yamanaka ◽  
Hideyo Okushi ◽  
Koji Kajimura ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Plasma Chemical Vapor Deposition ◽  
Transmission Electron ◽  
Excitonic Emission

AbstractThe band-A emission (around 2.8 eV) observed in high quality (device-grade) homoepitaxial diamond films grown by microwave-plasma chemical vapor deposition (CVD) was studied by means of scanning cathodoluminescence spectroscopy and high-resolution transmission electron microscopy. Recent progress in our study on homoepitaxial diamond films was obtained through the low CH4/H2 conditions by CVD. These showed atomically flat surfaces and the excitonic emission at room temperature, while the band-A emission (2.95 eV) decreased. Using these samples, we found that the band-A emission only appeared at unepitaxial crystallites (UC) sites, while other flat surface parts still showed the excitonic emission. High-resolution transmission electron microscopy revealed that there were grain boundaries which contained π-bonds in UC. This indicates that one of the origin of the band-A emission in diamond films is attributed to π bonds of grain boundaries.

Orientation relationship and interfacial structure between Nbsolid solution precipitates and α-Nb5Si3 intermetallics

2009 ◽  
Vol 24 (1) ◽  
pp. 192-197 ◽  
Author(s):  
G.M. Cheng ◽  
Y.X. Tian ◽  
L.L. He
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Transmission Electron Microscopy ◽  
Stress Concentration ◽  
High Resolution ◽  
Orientation Relationship ◽  
Interfacial Structure ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
High Resolution Tem

The orientation relationship (OR) and the interfacial structure between Nb solid solution (Nbss) precipitates and α-Nb5Si3 intermetallics have been investigated by transmission electron microscopy (TEM). The OR between Nbss and α-Nb5Si3 was determined by selected-area electron diffraction analyses as (222)Nb//(002)α and . High-resolution TEM images of the Nbss/α-Nb5Si3 interface were presented. Steps existed at the interface that acted as centers of stress concentration and released the distortion of lattices to decrease the interfacial energy. In addition, the interfacial models were proposed based on the observed OR to describe the atomic matching of the interface. The distribution of alloying elements at the Nbss/α-Nb5Si3 interface has also been investigated, and Hf was enriched at the interface to strengthen the grain boundary.

HRTEM Investigation of Precipitates in Al-Zn-In-Mg-Ti-Ce Anode Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 1036-1039
Author(s):  
Jing Ling Ma ◽  
Jiu Ba Wen ◽  
Yan Fu Yan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Hexagonal Structure ◽  
Orientation Relation ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Scanning Electron

The precipitates of Al-5Zn-0.02In-1Mg-0.05Ti-0.5Ce (wt %) anode alloy were studied by scanning electron microscopy, X-ray microanalysis, high resolution transmission electron microscopy and selected area electron diffraction analyses in the present work. The results show that the alloy mainly contains hexagonal structure MgZn2 and tetragonal structure Al2CeZn2 precipitates. From high resolution transmission electron microscopy and selected area electron diffraction, aluminium, Al2CeZn2 and MgZn2 phases have [0 1 -1]Al|| [1 -10]Al2CeZn2|| [-1 1 0 1]MgZn2orientation relation, and Al2CeZn2 and MgZn2 phases have the [0 2 -1]Al2CeZn2|| [0 1 -10]MgZn2orientation relation.

A transmission electron microscopy investigation of inverse melting in Nb45Cr55

1997 ◽  
Vol 12 (7) ◽  
pp. 1872-1884 ◽  
Author(s):  
W. Sinkler ◽  
C. Michaelsen ◽  
R. Bormann
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Amorphous Phase ◽  
Amorphous State ◽  
Transmission Electron ◽  
Microscopy Investigation ◽  
Electron Microscopy Investigation ◽  
Medium Range ◽  
High Resolution Tem ◽  
And Calorimetry

In inverse melting, a supersaturated crystalline phase transforms polymorphously under heat treatment to the amorphous state. Inverse melting of body-centered cubic (bcc) Nb45Cr55 is studied using transmission electron microscopy (TEM) and high resolution TEM (HRTEM). The crystalline to amorphous transformation is heterogeneous, initiating at the bcc grain boundaries. HRTEM reveals 2–3 nm domains with medium range order (MRO) in the amorphous phase. Preferred orientation of MRO domains is found on a scale corresponding to the precursor bcc grain size. Using HRTEM and calorimetry, MRO development in cosputtered Nb45Cr55 films is characterized and compared to that in the amorphous phase produced by inverse melting.

The Dodecagonal Quasicrystalline Telluride (Ta, V)1.6Te And Its Crystalline Approximant (TaV)97Te60

1998 ◽  
Vol 553 ◽  
Author(s):  
C. Reich ◽  
M. Conrad ◽  
F. Krumeich ◽  
B. Harbrecht
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Single Crystal ◽  
Edge Length ◽  
X Ray ◽  
Transmission Electron ◽  
The Impact

AbstractThe dodecagonal (dd) quasicrystalline tantalum telluride dd Ta1.6Te and the crystalline approximant Ta97Te60 have been modified by partly replacing tantalum by vanadium. The impact of the substitution on the structures has been studied by X-ray and electron diffraction and by high-resolution transmission electron microscopy. The layered-type approximant structure of Ta83V14Te60 was determined by single crystal X-ray means. The partitioning of vanadium on 21 out of 29 crystallographically inequivalent metal sites is referred to, but not controlled by the Dirichlet domain volume available at the sites. A HRTEM projection of dd (Ta, V)1.6Te onto the dodecagonal plane is analysed with respect to the arrangement of (Ta, V)151Te74 clusters on the vertices of an irregular aperiodic square-triangle tiling, the edge length of which corresponds to the distance between the centres of two such clusters. The clusters comprise about 1 nm thick corrugated lamellae which are periodically stacked by weak Te-Te interactions.

Design of 2D-nanocrystals in water: preparation, structure and functionalization

2018 ◽  
Vol 90 (5) ◽  
pp. 833-844
Author(s):  
Leonid Aslanov ◽  
Valery Zakharov ◽  
Ksenia Paseshnichenko ◽  
Aleksandr Yatsenko ◽  
Andrey Orekhov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Composition ◽  
High Resolution ◽  
Electron Diffraction ◽  
Single Crystal ◽  
Room Temperature ◽  
Energy Dispersive ◽  
X Ray ◽  
Transmission Electron

AbstractA new method for synthesis of 2D nanocrystals in water was proposed. The use of perfluorothiophenolate ions as surfactant allowed us to produce 2D single-crystal nanosheets of CaS at pH=9 and flat nanocrystals of PbS at pH=9 at room temperature. Mesocrystalline nanobelts of CdS and mesocrystals of PbS were obtained at pH=3–5 and pH=10–12, respectively. Morphology, structure and chemical composition of nanoparticles were characterized by high-resolution transmission electron microscopy, electron diffraction and energy dispersive X-ray spectroscopy. A mechanism of nanoparticles formation was discussed.

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