Ceramic high temp. superconductor prodn. - by pouring starting material into mould, heating, cooling, thermally treating in oxygen@ and cooling, for shield magnetic fields in switching elements

• Main Authors: UNTERNAEHRER, PETER, BAUMANN, THOMAS
• Format: Patent
• Language: English; German
• Published: 31.08.1993
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; ARTIFICIAL STONE; CEMENTS; CERAMICS; CHEMISTRY; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; CONCRETE; CRYSTAL GROWTH; ELECTRICITY; LIME, MAGNESIA; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; REFRACTORIES; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; SLAG; TREATMENT OF NATURAL STONE; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

Prodn. of a ceramic high temp. superconductor (HTSC) in the form of a large moulding made of a powdered starting material comprises: (a) pouring the material into a mould; (b) mould is heated to a 1st temp. to melt the material under low O2 partial pressure and sealed to a melt; (c) mould is cooled to a 2nd temp., in which the melt is solidified to moulding; (d) moulding (3) is thermally post treated in O2 to give a superconductor of high current density; (e) moulding (3) is cooled to room temp.; and (f) moulding (3) is removed from mould (2). Mould (2) is pref. annular and moulding (3) is a hollow cylinder having an inner dia. (d1) of more than 10 cm, height (h) of more than 1 cm and a wall thickness of less than 5 mm. Superconductor is pref. of formula Bi2 Sr2 Ca1 Cu2 O8+x or Ti2 Ba2Ca2Cu3O10+x. USE/ADVANTAGE - HTSC can be used to shield magnetic fields in switching elements.