Effects of morphology of Mg powder precursor on phase formation and superconducting properties of Mg11B2 low activation superconductor

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.

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Microstructure and superconducting properties of Bi-2223/Ag tapes fabricated in the pressing–melting–sintering process

Physica C Superconductivity ◽

10.1016/j.physc.2010.05.120 ◽

2010 ◽

Vol 470 (20) ◽

pp. 1388-1391 ◽

Cited By ~ 3

Author(s):

X.Y. Lu ◽

D. Yi ◽

H. Chen ◽

A. Nagata ◽

K. Sugawara

Keyword(s):

Sintering Process ◽

Superconducting Properties

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Effect of WC Addition on Phase Formation and Microstructure of TiC-Ni Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.55-57.353 ◽

2008 ◽

Vol 55-57 ◽

pp. 353-356

Author(s):

Nawarat Wora-uaychai ◽

Nuchthana Poolthong ◽

Ruangdaj Tongsri

Keyword(s):

Liquid Phase ◽

Tungsten Carbide ◽

Phase Formation ◽

Liquid Phase Sintering ◽

Precipitation Process ◽

Solid Solution Phase ◽

Binder Phase ◽

Sintering Process ◽

X Ray Diffraction ◽

X Ray

In this research, titanium carbide-nickel (TiC-Ni) composites, with tungsten carbide addition, were fabricated by using a powder metallurgy technique. The TiC-Ni mixtures containing between 0-15 wt. % tungsten carbide (WC), were compacted and then sintered at 1300°C and 1400°C, respectively. The phase formation and microstructure of the WC-added TiC-Ni composites have been investigated by X-ray diffraction and scanning electron microscopy techniques. Mechanical properties of these composites were assessed by an indentation technique. The X-ray diffraction patterns showed no evidence of tungsten rich phases in the sintered WC-added cermets. This indicates that during the sintering process, tungsten carbide particles were dissolved in metallic binder phase (Ni phase) via dissolution/re-precipitation process during liquid phase sintering. The liquid phase formed during sintering process could improve sinterability of TiC-based cermets i.e., it could lower sintering temperatures. The TiC-Ni composites typically exhibited a core-rim structure. The cores consisted of undissolved TiC particles enveloped by rims of (Ti, W)C solid solution phase. Hardness of TiC-Ni composites increased with WC content. Sintering temperature also had a slight effect on hardness values.

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Effect of V Additions on Bi2223 Phase Formation and Superconducting Properties of (Bi,Pb)2Sr2Ca2Cu3Oz

Advances in Cryogenic Engineering Materials ◽

10.1007/978-1-4757-9056-6_74 ◽

1998 ◽

pp. 561-567

Author(s):

H. Maeda ◽

K. Kakimoto ◽

M. Kikuchi ◽

J. O. Willis ◽

K. Watanabe ◽

...

Keyword(s):

Phase Formation ◽

Superconducting Properties

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Sintering of Textured YBa2Cu307-x Under Intensive 60Co Gamma Irradiation

MRS Proceedings ◽

10.1557/proc-354-723 ◽

1994 ◽

Vol 354 ◽

Cited By ~ 1

Author(s):

Elvira M. Ibragimova ◽

Eldar M. Gasanov ◽

Makhmud Kalanov ◽

Marquis A. Kirk ◽

Ken C. Goretta

Keyword(s):

Gamma Irradiation ◽

Dose Rate ◽

Subsurface Layer ◽

Gamma Dose ◽

Ordered Structure ◽

Sintering Process ◽

Superconducting Properties ◽

Oxygen Sublattice ◽

60Co Gamma ◽

Sem Analyses

AbstractA study of structural and superconducting characteristics of YBa2Cu307-x ceramics sintered after and in the course of gamma-irradiation is reported. Using X-difraction and SEM analyses and transport measurements, it has been shown that mainly the subsurface layer of crystallites and intergrain contacts are affected by the irradiation by means of sorption/desorption of oxygen and ordering/disordering in oxygen sublattice, which depends on gamma dose rate and dose. The irradiation provides the sintering process with an additional superthermal energy to form the orthorhombic well-ordered structure and to obtain dense ceramics possessing strong intergrain contacts and improved and stable superconducting properties

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