Electron Microscopy Studies of Potassium Sodium Niobate Ceramics

2005 ◽  
Vol 11 (6) ◽  
pp. 572-580 ◽  
Author(s):  
Darja Jenko ◽  
Andreja Benčan ◽  
Barbara Malič ◽  
Janez Holc ◽  
Marija Kosec
Keyword(s):  
Electron Microscopy ◽  
Secondary Phase ◽  
Nominal Composition ◽  
Potassium Sodium Niobate ◽  
Transmission Electron Microscopy Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Ferroelectric Domains ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

Using electron microscopy, K0.5Na0.5NbO3 (KNN) ceramics sintered at 1030°C for 8 h and 1100°C for 2 and 24 h was studied. The scanning electron microscopy and X-ray spectrometry revealed that the materials consisted of a matrix phase in which the (Na+K)/Nb ratio corresponded closely to the nominal composition and a small amount of Nb-rich secondary phase. A bimodal microstructure of cube-shaped grains was revealed in the fracture and thermally-etched surfaces of the KNN. In the ceramics sintered at 1100°C, the larger grains (up to 30 μm across), contained angular trapped pores. The transmission electron microscopy analysis revealed that the crystal planes of the grains bordering the intragranular pore faces were of the {100} family with respect to the simple perovskite cell. Ferroelectric domains were observed in the grains of this material.

Nanometric AlNi Precipitation in a 84.68 wt.% Cu-11.25 wt.%Al-4.07 Wt%Ni Shape Memory Alloy

2013 ◽  
Vol 334-335 ◽  
pp. 1-6
Author(s):  
Khaled Hamouda ◽  
S.M. Chentouf ◽  
M. Bouabdallah ◽  
H. Cheniti ◽  
N. Amimer
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Room Temperature ◽  
Nominal Composition ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

A shape memory alloy with a nominal composition of 84.68 wt.% Cu-11.25 wt.%Al-4.07 wt.%Ni, has been studied. Polycrystalline specimens have been quenched into water at room temperature, after heat treatment of 15 minutes at a high temperature of 1123 K. Two successive cycles from room temperature to 923 K and inversely have been performed on the non equilibrium samples. The microstructural study presented in this work has been performed using TEM (Transmission Electron Microscopy) analysis, STEM (Scanning Transmission Electron Microscopy) analysis, X-ray diffraction analysis at a variable temperature. Nanometric phase precipitation of AlNi type was observed to appear in this alloy.

Growth and Characterization of C-Axis Oriented YBa2Cu3O7-x/PrBa2Cu3O7-x Bilayers

1999 ◽  
Vol 13 (09n10) ◽  
pp. 1005-1010 ◽  
Author(s):  
C. Beneduce ◽  
F. Bobba ◽  
M. Boffa ◽  
M. C. Cucolo ◽  
A. M. Cucolo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
Transmission Electron Microscopy Analysis ◽  
X Ray ◽  
Resistivity Measurements ◽  
Transmission Electron ◽  
High Oxygen Pressure ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

We report on the preparation and characterization of YBa 2 Cu 3 O 7-x/ PrBa 2 Cu 3 O 7-x bilayers onto (100) SrTiO 3 substrates. The samples have been prepared by sequential dc sputtering processes in high oxygen pressure from stoichiometric targets. The structural characterization of the YBa 2 Cu 3 O 7-x and PrBa 2 Cu 3 O 7-x films and of the bilayers has been performed by means of X-ray diffraction. The Scanning Electron Microscopy analysis has showed that the film surfaces are flat and free of precipitates. A detailed study of the interfaces has been performed by Transmission Electron Microscopy analysis. The electrical resistivity measurements showed for the YBa 2 Cu 3 O 7-x films sharp superconducting transitions at 91.5 K and critical current density of about 106 A/cm 2 at 77 K, while for the PrBa 2 Cu 3 O 7-x films a semiconductor-like behavior has been observed.

X-ray diffraction and transmission electron microscopy analysis of ordering and structure in Al1−xInxAs thin films

2000 ◽  
Vol 15 (1) ◽  
pp. 45-55 ◽  
Author(s):  
R. L. Forrest ◽  
J. Kulik ◽  
T. D. Golding ◽  
S. C. Moss
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Short Range ◽  
X Ray Diffraction ◽  
Transmission Electron Microscopy Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Short Range Ordering ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

This paper presents an x-ray diffraction and transmission electron microscopy analysis of Al1−xInxAs grown by molecular beam epitaxy. Two samples grown on (001) InP at temperatures of 370 and 400 °C are characterized. The first, which contains a high density of twin lamellae, exhibits triple-period short-range ordering with a rather short correlation range normal to the (111) planes. Within these (individual) planes, the concentration, however, is uniform over a considerably greater distance, leading to a highly anisotropic scattering. This is the first observation of triple-period short-range ordering in a sample that exhibits 2 × 1 surface reconstruction. The second sample exhibits CuPt-type short-range ordering with scattering that is significantly streaked, suggestive of lamellar-shaped ordered domains. Both samples contain high densities of stacking faults leading to additional sharp streaking along symmetry-allowed 〈111〉 directions.

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