Formation route of higher member phases from lower ones in the Tl-Ca-Ba-Cu-O system

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Journal of Materials Research; (USA)

DOI:https://doi.org/10.1557/JMR.1990.1860· OSTI ID:6484132

Cheung, C T; Ruckenstein, E ^[1]

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1. Department of Chemical Engineering, State University of New York at Buffalo, Buffalo, NY (USA)

An experiment was designed to follow the formation of higher member phases from lower member phases in the Tl{sub 2}Ca{sub {ital n}{minus}1}Ba{sub 2}Cu{sub {ital n}}O{sub 2{ital n}+4} series. Coarse particles of the lower member phase were directly interfaced with various Ca-Cu-O sources and the pressed pellets were heat treated in air, in a gold pocket, at 850 {degree}C, for a period of 2--4 h. The reacted samples were polished and examined by scanning electron microscopy with energy dispersive x-ray spectrometry analysis (EDS). For the 2021 based reaction systems, the results suggest that the 2122 phase can be formed via reactions which involve the decomposition of the 2021 phase, the formation of a complex liquid phase, and finally the reaction between this liquid phase and a Ba/Ca compound. The formation of the 2223 phase from the 2122 phase is likely to follow a similar reaction route. The involvement of a liquid phase in the formation of the higher member phases may lead to a glassy phase, and hence to a barrier to the achievement of a high critical current density.

• OSTI ID: 6484132
• Journal Information: Journal of Materials Research; (USA), Journal Name: Journal of Materials Research; (USA) Vol. 5:9; ISSN JMREE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL CURRENT
CURRENT DENSITY
CURRENTS
DATA
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
FLUIDS
HEAT TREATMENTS
HIGH-TC SUPERCONDUCTORS
INFORMATION
LIQUIDS
LOW TEMPERATURE
MICROSCOPY
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SCANNING ELECTRON MICROSCOPY
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THALLIUM COMPOUNDS
THALLIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
VERY HIGH TEMPERATURE