Two-powder processing of Bi-2223 - an update

Conference · Fri Jul 29 04:00:00 EDT 1994

OSTI ID:41735

Dorris, S E; Pitz, M A; Dawley, J; Lanagan, M T; Vasanthamohan, N; Maroni, V A; Luo, J S ^[1]

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1. Argonne National Lab., IL (United States)

The patented two-powder process of ANL reproducibly yields more uniform and complete formation of Bi-2223 than does the typical mixed-phase powder process. In the two-powder process, intermediate precursors of lead-doped 2212 and CaCuO{sub 2} (which decomposes to Ca{sub 2}CuO{sub 3} + CuO) are made separately, then combined and reacted inside the silver sheath of powder-in-tube (PIT) specimens. This presentation describes efforts to increase the Jc of Bi-2223 PIT tapes by improving the alignment and connectivity of Bi-2223 grains. It will be shown that milling of precursor powders causes pickup of carbon, which resides at grain boundaries and disrupts grain-to-grain connectivity, but that the carbon-content can be reduced by vacuum calcination of the mixed powder (i.e. 2212 + CaCuO{sub 2}) before it is loaded into the silver tube. In addition, it is shown that slight changes in overall composition dramatically affect the final microstructures and may be important for improving the properties of tapes. Finally, a silver wire-in-tube method is described as a method for possibly improving grain alignment by increasing the interfacial area between silver and superconductor.

• Research Organization: USDOE Assistant Secretary for Energy Efficiency and Renewable Energy, Washington, DC (United States)
• OSTI ID: 41735
• Report Number(s): CONF-9407153--Vol.1; ON: DE95005058
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
BISMUTH OXIDES
CALCIUM OXIDES
CARBON
COPPER OXIDES
CRITICAL CURRENT
FABRICATION
GRAIN ORIENTATION
HEAT TREATMENTS
LEAD
POWDERS
SUPERCONDUCTING WIRES
TECHNOLOGY TRANSFER