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Bonded Superconducting Powder for Magnetic Shielding

IP.com Disclosure Number: IPCOM000119325D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Chance, DA: AUTHOR [+4]

Abstract

Disclosed are magnetic shielding materials made from composite mixes of high Tc superconductor particles and a binder by pressing them into various shapes at temperatures close to room temperature. A metallic binder, such as Pb, is particularly effective in forming such materials.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 83% of the total text.

Bonded Superconducting Powder for Magnetic Shielding

      Disclosed are magnetic shielding materials made from
composite mixes of high Tc superconductor particles and a binder by
pressing them into various shapes at temperatures close to room
temperature.  A metallic binder, such as Pb, is particularly
effective in forming such materials.

      Superconducting powder of the material YBa2C3O7-x is prepared
by a standard ceramic process.  Y2O3, BaCO3 and CuO were mixed in a
ball mill, calcined at 950oC for 24 hours and cooled slowly to room
temperature at 100oC per hour. The calcined powder was then crushed
to form particles.  A second calcining and regrinding is used to
improve the quality of the powder.  The powder was then formed into
various articles which are shielding to magnetic flux at liquid
nitrogen temperature by two processes as follows:
1.   The superconducting powder was mixed with -325 mesh Pb particles
by dry ball milling or by hand in a mortar and pestel.  The mixture
was then pressed in a die at 100oC and 50,000 psi for 1 hour and
cooled slowly to room temperature.
2.   The superconductor powder was mixed with an organic binder
(e.g., a solution polyvinyl butyral and di-octyl phthalate in
methanol and methyl isobutyl ketone) and cast to obtain
self-supporting "green" sheets after the solvents have evaporated.
The "greensheets" were laminated together at 600 psi and 85oC to form
articles, such as a 30-mil-thick board.

      An example...