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Argonne
National Laboratory: High-Temperature Superconductivity R&D
in Brief
Since the discovery
of superconductivity at temperatures exceeding the boiling point
of liquid nitrogen in 1986, the Argonne National Laboratory has
been actively engaged in research aimed at exploiting high critical-temperature
superconducting (HTS) materials for electric power applications.
With sustained funding from the Department of Energys (DOEs)
Office of Energy Efficiency and Renewable Energy (dating back to
the late 1980s), Argonne has conducted forefront scientific
investigations that have strongly contributed to the resolution
of progress-limiting issues and to the discovery of improved methodologies
for fabricating and implementing composite wire and thin film HTS
embodiments. The program at Argonne involves scientists and engineers
from four divisions of the Laboratorythe Energy Technology
Division, the Chemical Technology Division, the Materials Science
Division, and the Energy Systems Division. In conjunction with the
research and development activities, Argonne staff continuously
monitor and assess worldwide progress in the development of HTS
technology.
In the course of its superconductor
research, Argonne has forged scores of collaborations with industries,
universities, and other national laboratories. Through a cooperative
research and development agreement with American Superconductor,
in place for over ten years now, Argonne has participated in the
highly regarded Wire Development Group (WDG), which also includes
Los Alamos National Laboratory and the University of Wisconsin.
The WDG pioneered the fabrication of long-length, silver-sheathed
Bi-2223 (Ag/Bi-2223) composite conductors suitable for cables, motors,
generators, fault current limiters, etc. In particular, aspects
of the heat treatment used by American Superconductor to manufacture
Ag/Bi-2223 wire benefited significantly from research done at Argonne.
Since 1992, Argonne has collaborated with Intermagnetics General
Corp. (IGC) in establishing the processing science and technology
that is needed to manufacture Bi-2223 tapes. Long-length Bi-2223
tapes fabricated by IGC are used in a prototype fault-current limiter
(FCL). Vacuum-calcination for synthesizing phase-pure superconductor
powders, an R&D-100-Award-winning technique developed at Argonne,
was transferred to Superconductive Components, Inc., who uses it
to manufacture superconductor powders and market them worldwide.
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In recent years, the emphasis of Argonnes
HTS technology effort has shifted to YBa2Cu3O7(YBCO)
-coated conductors. This work focuses primarily on the development
of the inclined substrate deposition method for producing suitably
textured templates on which continuous, biaxially textured YBCO
films can be grown. The objective of this research is to develop
a fabrication method that is adaptable to the efficient and economical
manufacturing of long-length coated conductors. Test specimens carrying
over 0.5 MA/cm2 have been produced by methods that have
the potential to meet DOEs cost/performance goals. In the
area of coated conductors, Argonne collaborates with AMSC, IGC-SuperPower,
and Universal Energy Systems, Inc. Our industrial partners have
made lengths (>1 m) of coated conductors that carry >100 amps/cm-width
of tape.
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In addition to Argonne's research into the optimization of conductor
performance and the fabrication of superconducting devices, it has
made strong contributions over the past decade in the area of conductor
characterization. These contributions have made excellent use of
unique Argonne facilities, such as the Electron Microscopy Center,
the Advanced Photon Source, and the Intense Pulsed Neutron Source.
Raman microspectroscopy methods that were developed and utilized
by Argonne staff have contributed seminal insights about phase evolution
during the synthesis of HTS ceramics. Magneto-optic imaging, another
R&D-100-Award-winning technique, was developed at Argonne to
map the current distribution in HTS and provided valuable feedback
for the optimization of conductor performance. Argonne staff have
also investigated critical factors that influence current transport
across individual grain boundaries in HTS. Argonnes characterization
studies have produced seminal information about the chemical and
mechanical properties of HTS materials, the relationships between
microstructure and conductor performance, and the effects of processing
conditions on the quality of fully fabricated conductors.
In collaboration with industrial partners, Argonne is developing
a flywheel energy storage system and an FCL that are based on HTS
materials. Argonne continues to collaborate with industry, utilities,
universities, and other national laboratories in the development
and application of HTS materials.
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