CO sub 2 decomposition kinetics of YBa sub 2 Cu sub 3 O sub 7 minus x via in situ electrical conductivity measurements

Journal Article · Mon Jul 01 00:00:00 EDT 1991 · Journal of Materials Research; (USA)

DOI:https://doi.org/10.1557/JMR.1991.1393· OSTI ID:5560923

Cooper, E A; Gangopadhyay, A K; Mason, T O ^[1]; Balachandran, U ^[2]

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1. Northwestern University, Department of Materials Science and Engineering and Science and Technology Center for Superconductivity, Evanston, Illinois 60208 (USA)
2. Argonne National Laboratory, Materials and Components Technology Division and Science and Technology Center for Superconductivity, Argonne, Illinois 60439 (USA)

{ital In} {ital situ} electrical conductivity measurements were employed to study the kinetics of decomposition of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} in flowing 5% CO{sub 2}/95% O{sub 2} atmosphere at 815 {degree}C. Three regimes could be observed in the decay of the conductivity with time, interpreted as corresponding to nucleation over the initial 5--10 min, rapid formation of Y{sub 2}Cu{sub 2}O{sub 5}, BaCO{sub 3}, and CuO between 10 min and 1 h, and finally transition to the formation of Y{sub 2}BaCuO{sub 5}, BaCO{sub 3}, and CuO at longer times. The absence of dispersion in impedance measurements as a function of frequency together with the gradual decay of conductivity (roughly corresponding to the remaining volume fraction of YBa{sub 2}Cu{sub 3}O{sub 7{minus}}{sub {ital x}}) indicates that not all grain boundaries are involved in the decomposition process.

• OSTI ID: 5560923
• Journal Information: Journal of Materials Research; (USA), Journal Name: Journal of Materials Research; (USA) Vol. 6:7; ISSN JMREE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE
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ALKALINE EARTH METAL COMPOUNDS
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ELECTRIC CONDUCTIVITY
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GRAIN BOUNDARIES
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NUCLEATION
OXIDES
OXYGEN COMPOUNDS
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