Plates of melt-textured YBa2Cu3O7−x superconductors with long crystals

Larsen, Jørgen Gutzon; Dam, N.E.; Jacobsen, Claus Schelde; Bærendtsen, H.D.; Sommerschield, J.G.

doi:10.1016/0921-4534(93)90803-x

Cited by 6 publications

(1 citation statement)

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“…The depletion of liquid phases from the 0953-2048/98/050523+12$19.50 c 1998 IOP Publishing Ltd interior of the material will also alter the stoichiometry and hinder the grain growth and texturing process. These drawbacks therefore limited the fabrication of large and complex shapes and the only shapes reported so far, by melt processing, in the literature are either those of discs or bars [10][11][12]. Due to the ceramic nature, and due to various kinds of defects mentioned above, the melt processed 123 materials posed difficulties in machining into suitable shapes for applications.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of textured (RE = Y, Gd) composites by infiltration and growth of preforms by liquid phases

Reddy

Rajasekharan

1998

Supercond. Sci. Technol.

123

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A process for the fabrication of high-quality and near-net-shaped superconducting specimens of (Y-123) with uniformly distributed fine (Y-211) is discussed. The process involves the fabrication of 211 preforms by conventional ceramic routes such as uniaxial and isostatic pressing, injection moulding and slip casting, and pressureless infiltration basically from a reservoir containing liquid phases. A compact of 123 or 123 rich in liquid phases(s), acting as a source of liquid phases, is placed in contact with the 211 preform, and heated above the peritectic temperature of 123. The liquid from the source compact infiltrates the 211 filler and the peritectic reaction occurring between the preform material (211) and the matrix (liquid phases) during slow cooling from the peritectic temperature results in the growth of 123 with uniformly distributed fine 211 particles. We have also demonstrated that the present process can be extended to the fabrication of other rare earth (RE) superconductors where a solid solution of the kind occurs due to comparable size of the RE and Ba atoms, by choosing the RE = Gd system as an example. Herein the advantages and bounds of the process are reviewed; the effect of various cooling rates on the growth kinetics of 123 and the resulting macro- and microstructures are discussed. Fabrication of composites containing fine and very uniformly distributed Ag is also demonstrated by the process. Comparisons are made between the characteristics of the samples produced in the present process and the existing melt texturing process. The utility of the process is demonstrated by the fabrication of a three-dimensional component - a hollow cylinder.

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Section: Introductionmentioning

confidence: 99%