Isothermal melting and continuous isothermal melt texturing of YBaCuO

Author

Arnott, M. ; Glowacki, B.A. ; Soylu, B. ; Evetts, J.E.

Author_Institution

Dept. of Mater. Sci., Cambridge Univ., UK

Volume

3

Issue

1

fYear

1993

fDate

3/1/1993 12:00:00 AM

Firstpage

1037

Lastpage

1040

Abstract

A study of isothermal melt texturing, whereby the O/sub 2/ partial pressure dependence of the melting point of YBCO is exploited to substitute for the slow cooling and temperature gradient of the melt textured growth method, is presented. A melt pool is produced by lowering the O/sub 2/ partial pressure locally with a jet of Ar directed onto the center of a YBCO slab within an O/sub 2/-filled furnace, and its development is investigated as a function of temperature, Ar/O/sub 2/ ratio, and time. If the pool is allowed to cool slowly, a large grained microstructure is formed, with 123 crystals of around 1-mm average cross section. The critical current density is around 2000 A/cm/sup 2/ at 77 K (B=0 T). In a further set of experiments the jet is driven slowly across the surface, melting a track. When the jet moves sufficiently slowly, a large grained microstructure is formed by continuous, isothermal processing.<>

Keywords

barium compounds; critical current density (superconductivity); crystal microstructure; crystallisation; high-temperature superconductors; melting; texture; yttrium compounds; 123 crystals; 77 K; Ar/O/sub 2/ ratio; O/sub 2/ partial pressure dependence; YBCO; YBa/sub 2/Cu/sub 3/O/sub 7- delta /; continuous isothermal melt texturing; critical current density; high temperature superconductors; isothermal melting; large grained microstructure; melt pool; melting point; Argon; Chemicals; Cooling; Furnaces; Isothermal processes; Microstructure; Superconductivity; Temperature; Testing; Yttrium barium copper oxide;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.233877

Filename

233877