Processing of YBa sub 2 Cu sub 3 O sub 7 tapes from a molten salt precursor

Technical Report · Mon Sep 10 04:00:00 EDT 1990

DOI:https://doi.org/10.2172/6617452· OSTI ID:6617452

Millis, R P

A novel process for forming a viscous nitrate precursor of the superconducting YBa{sub 2}Cu{sub 3}O{sub 7-x} material, without the use of binders or plasticizers, is described. The precursor material is formed at 90{degree}C from low melting salts such as Ba(OH){sub 2}{center dot}8H{sub 2}O, Cu(NO{sub 3}){sub 2}{center dot}3H{sub 2}O and an aqueous nitrate solution of yttrium. The viscous precursor behaves as a concentrated suspension, being composed of particles of Ba(NO{sub 3}){sub 2} and Cu{sub 2}(OH){sub 3}(NO{sub 3}) which are bound'' together by a gelatinous yttrium nitrate phase. This material has shown desirable properties for the formation of thin tapes through the doctor blade tape casting process. A technique is described for forming thin sheets of superconducting YBa{sub 2}Cu{sub 3}O{sub 7-x} by tape casting a viscous molten salt precursor which shows desirable rheological properties without the addition of binders or plasticizers. The drying of these tapes has shown the formation of a yttrium nitrate binder phase to be important in reducing cracking. The firing of these tapes has shown that the metal nitrates in the dried material decompose individually when heated in an oxygen atmosphere and react to form the superconducting phase above 750{degree}C. The decomposition of the nitrates has resulted in extensive porosity in the fired tapes. The superconducting phase was formed in a single heat treatment and oxygen anneal. Magnetometer measurements have shown a transition temperature of {Tc} = 88K at 10% of 50 Oe field cooled saturation value.

• Research Organization: Ames Lab., IA (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6617452
• Report Number(s): IS-T-1489; ON: DE90017656
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CASTING
CHALCOGENIDES
CHEMICAL PREPARATION
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
DIFFRACTION
DRYING
FABRICATION
HIGH-TC SUPERCONDUCTORS
MOLTEN SALTS
OXIDES
OXYGEN COMPOUNDS
RHEOLOGY
SALTS
SCATTERING
SHEAR
SUPERCONDUCTORS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
VISCOSITY
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS
YTTRIUM OXIDES