Effect of Thermal Processing on the Microstructures and Superconducting Properties of YBa2Cu3Oy

1987 ◽  
Vol 99 ◽  
Author(s):  
K. Gotoh ◽  
H. Enomoto ◽  
K. Iida ◽  
Y. Takano ◽  
N. Mori ◽  
...  
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Low Temperature ◽  
Sample Preparation ◽  
Thermal Processing ◽  
Superconducting Phase ◽  
Sintering Process ◽  
Superconducting Properties ◽  
Cooling Process ◽  
High Tc

ABSTRACTThe effect of thermal processing in the sample preparation of YBa2Cu3Oy has been investigated systematically on microstructures and electrical properties. The grain size was found to grow preferably during the cooling process rather than during the sintering process. The high Tc superconducting phase appears around 500 C in this thermal processing. The annealing experiment shows that the grains still grow at low temperature such as 300 °C.

SUPERCONDUCTING PROPERTIES OF THE HIGH Tc SUPERCONDUCTING Er-Ba-Cu-O COMPOUND

1989 ◽  
Vol 03 (03) ◽  
pp. 441-444 ◽  
Author(s):  
S. M. M. R. NAQVI ◽  
FIROZ AHMAD ◽  
JAWAID ALAM ◽  
SHARFUDDIN AHMAD
Keyword(s):  
Superconducting Phase ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Zero Resistance ◽  
Two Phases

Two batches of Er-Ba-Cu-O superconductors have been prepared. The zero resistance temperature is 86 K with T c onsets at 99 K and 92 K respectively. Susceptibility measurements show superconducting phase at LN 2. X-ray diffraction results indicates two phases, the superconducting being the major one.

The Governance of Sintering Regimes on the Properties and Ageing Resistance of Y-TZP Ceramic

2012 ◽  
Vol 545 ◽  
pp. 81-87 ◽  
Author(s):  
Sivakumar Sivanesan ◽  
Ramesh Singh ◽  
Chin Kong Leong
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Phase Transformation ◽  
Low Temperature ◽  
Dwell Time ◽  
Superheated Steam ◽  
Xrd Analysis ◽  
Sintering Process ◽  
Monoclinic Symmetry ◽  
The Poor

The retention of nanometric microstructures is a challenge in any presureless sintering process. Grain size influences mechanical properties and grain coarsening retards densification upon sintering, thus resulting in the poor overall product properties. Hence, it is important to select, among others a suitable sintering regime which promotes densification and retards microstructure coarsening. In this work, Y-TZP ceramic bodies were fabricated under four different sintering regimes to investigate the governance of conventional Single-Stage Sintering (SSS) with 1 min and 2 h dwell time, and comparing their performance with bodies produced by Two-Stage Sintering (TSS). It was revealed that TSS sintered samples, yielded better properties than the SSS samples sintered at 1400°C with a dwell time of 2 hours. In the hydrothermal ageing test, TSS samples did not undergo the low-temperature degradation via the martensitic phase transformation of tetragonal to monoclinic symmetry. Nevertheless, it was found by XRD analysis that Y-TZP ceramics sintered by the SSS method using a short dwell time of 1 minute was effective in maintaining the tetragonal phase stability after 50 hours of exposure in superheated steam conditions.

Dielectric properties of (SWCNTs)x GdBa2CuO7−δ superconductor nanocomposites

2017 ◽  
Vol 31 (31) ◽  
pp. 1750290 ◽  
Author(s):  
M. Anas ◽  
S. Ebrahim ◽  
I. G. Eldeen ◽  
R. Awad ◽  
A. I. Abou-Aly
Keyword(s):  
Dielectric Properties ◽  
Phase Formation ◽  
Dielectric Response ◽  
Single Walled Carbon Nanotubes ◽  
Superconducting Phase ◽  
Sintering Process ◽  
Superconducting Properties ◽  
Solid State Reaction Technique ◽  
Micro Cracks ◽  
Walled Carbon Nanotubes

Gd-123 superconducting phase was prepared by solid-state reaction technique. Single-walled carbon nanotubes (SWCNTs) were added in Gd-123 superconducting matrix with different concentrations during the final sintering process to obtain (SWCNTs)[Formula: see text] GdBa2Cu3O[Formula: see text] (x = 0.0–0.1 wt.%) nanoparticles–superconductor composite. The influence of SWCNTs addition on the phase formation, structural, morphological, superconducting and dielectric properties of Gd-123 phase was investigated. It was found that SWCNTs addition enhance the phase formation and does not change the crystal structure of the host Gd-123 superconducting phase. The superconducting properties of Gd-123 samples were improved after the addition of SWCNTs up to x = 0.06 wt.% due to the enhancement in intergrain connectivity by healing up of micro-cracks and reduction of defects, while these properties were retarded with further increase in x. The dielectric response of (SWCNTs)[Formula: see text] Gd-123 superconducting phase with x = 0.0, 0.01, 0.04, 0.05, 0.06 and 0.1 wt.% was measured from 100 KHz to 5 MHz at 77 K. The results reveal that for both real ([Formula: see text]) and imaginary ([Formula: see text]) parts of dielectric constant, the frequency of dispersion increased by increasing SWCNTs amount up to 0.06 wt.%, then this frequency shifted to lower values for x [Formula: see text] 0.06 wt.%. The results were discussed according to the presence and interference of both interfacial and dipolar polarizations.

High-Tc superconductor/polymer composites. Modeling of abnormal electrical properties at low temperature

1994 ◽  
Vol 230 (3-4) ◽  
pp. 246-254 ◽  
Author(s):  
A. Benlhachemi ◽  
J.R. Gavarri ◽  
J. Musso ◽  
C. Alfred-Duplan ◽  
J. Marfaing
Keyword(s):  
Electrical Properties ◽  
Low Temperature ◽  
Polymer Composites ◽  
High Tc ◽  
High Tc Superconductor

Effects of Doped Cu, Mn on Electrical Properties of SrTiO3-Based Varistor Ceramics

2011 ◽  
Vol 399-401 ◽  
pp. 783-787
Author(s):  
Ning Zhang Wang ◽  
Zhang Wen
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Solid State ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Nonlinear Coefficient ◽  
Solid State Reaction Method ◽  
Sintering Process ◽  
Reaction Method ◽  
Sintering Conditions

CuO and MnCO3 doped SrTiO3-based multifunction ceramics were prepared respectively with solid state reaction method under vacuum condition. The electrical properties’ change with the oxidation temperature and microstructure were investigated. The results show that acceptor dopants behaves differently with the same sintering conditions. CuO-doped ceramic possess relative higher dielectric loss, dielectric constant and relative lower nonlinear coefficient, varistor voltage in contrast with MnCO3 doped ceramic with the same contents under the same sintering conditions. The grain size of CuO-doped sample is significantly larger than the sample doped with MnCO3. The grain distributions of CuO-doped sample is more homogeneous. The electrical properties of the ceramics are different due to the different behaviors of CuO and MnCO3 accepter dopants during the sintering process.

Annealing Effects on Properties of High Tc YBa2Cu3O7−x Ceramics

1987 ◽  
Vol 99 ◽  
Author(s):  
Shin-Guang Shyu ◽  
R. F. Louh ◽  
R. C. Buchanan
Keyword(s):  
Superconducting Phase ◽  
Superconducting Properties ◽  
High Tc ◽  
X Ray ◽  
Heat Treated ◽  
Annealing Effects ◽  
Overall Resistance

ABSTRACTHigh Tc superconducting YBa2Cu3O7−x ceramics were prepared from the appropriate oxide constituents and heat treated under various conditions to determine the effects of annealing on superconducting properties. Sintered samples (900–920°C) were air cooled at 5°/min followed by annealing in oxygen or air at 500°C/12 hr. Resistance measurements, SQUID, SEM, and x-ray analysis were used to characterize the samples, which were of 38% porosity. Results showed all samples to be superconducting with TC(O) 84K. Superconducting properties of the air and oxygen annealed samples were equivalent but showed lower overall resistance and 30% higher superconducting phase (30 to 70 K) compared to the air cooled samples.

scholarly journals Structural, microstructural, electrical properties of lanthanum doped-bismuth titanate ceramics prepared by low temperature combustion synthesis

2017 ◽  
Vol 49 (2) ◽  
pp. 107-115 ◽  
Author(s):  
Azlan Al-Amani ◽  
Mohd Noor
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Low Temperature ◽  
Combustion Synthesis ◽  
Bismuth Titanate ◽  
Low Temperature Combustion ◽  
Orthorhombic Distortion ◽  
Temperature Combustion ◽  
The Difference ◽  
Titanate Ceramics

In this work, lanthanum doped-bismuth titanate with different contents were successfully prepared by low-temperature combustion synthesis, and subsequently, sintered at 1000 oC for 3 hours. Their structural, microstructural and electrical were systematically studied. It was found that the structural distortion of orthorhombic structure tends to transforms to a tetragonal with the increase in La content. This change is most probably due to relaxations of orthorhombic distortion and octahedral tilting because of the difference in the ionic radius of Bi3+ and La3+. Upon increasing of La content, the grain size remarkable decreases resulted in uniform grain size with better relative density. Thus, the electrical properties of La doping were greatly improved in comparison to pure sample.

Electrical properties of Bi(Ni1/2Ti1/2)O3–PbTiO3 high-TC piezoelectric ceramics fabricated by the microwave sintering process

2014 ◽  
Vol 179 ◽  
pp. 36-40 ◽  
Author(s):  
Shenglin Jiang ◽  
Zhongjiang Zhu ◽  
Ling Zhang ◽  
Xue Xiong ◽  
Jinqiao Yi ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Microwave Sintering ◽  
Piezoelectric Ceramics ◽  
Sintering Process ◽  
High Tc

Bulk standards for low-temperature biological x-ray microanalysis

1984 ◽  
Vol 42 ◽  
pp. 282-283
Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  
Keyword(s):  
Phase Separation ◽  
Low Temperature ◽  
Analytical Method ◽  
Salt Solutions ◽  
Absolute Concentration ◽  
Cooling Process ◽  
X Ray ◽  
The Absolute ◽  
Analytical Procedures ◽  
Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

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