PROCESSAMENTO DO SUPERCONDUTOR CERÂMICO Bl-2212 POR FUSÃO PARCIAL

The Bi2Sr2CaCu2O8+x (Bi-2212) oxide is one of the main high-temperature superconductors for applications development. The present work reports our investigations on the partial melt processing of bulk Bi-2212. Precursors with different nominal compositions are mixed with silver powder, since this me...

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Bibliographic Details
Published in:Tecnologia em metalurgia, materiais e mineração materiais e mineração, 2008-04, Vol.4 (4), p.32
Main Authors: Polasek, Alexander, Sena, Carla Vital de, Sens, Márcio Antônio, Assunção, Fernando Cosme R, Serra, Eduardo Torres
Format: Article
Language:Portuguese
Subjects:
Bismuth
Bulk density
Cooling
Critical current (superconductivity)
Decomposition
Densification
Grains
Liquid nitrogen
Melting
Molds
Silver
Solid phases
Thermal analysis
Transport
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Summary:The Bi2Sr2CaCu2O8+x (Bi-2212) oxide is one of the main high-temperature superconductors for applications development. The present work reports our investigations on the partial melt processing of bulk Bi-2212. Precursors with different nominal compositions are mixed with silver powder, since this metal lowers Bi-2212 melting temperature and is believed to enhance its properties. The precursors are then uniaxially pressed into silver molds. Samples are analyzed by means of DTA, XRD and SEM/EDS. The critical current (Ic) of the processed blocks is measured by using the four-point method, at the liquid nitrogen temperature (77 K). By partial melting, the Bi-2212 phase decomposes into liquid and solid phases. Slow cooling tends to promote bulk densification and texturization of Bi-2212 grains, favoring thus the current transport. However, precipitation of secondary phases may decrease the current transport capacity of the material. Samples with critical currents above 100 A have been obtained.
ISSN:2176-1515
2176-1523
DOI:10.4322/tmm.00404006