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Composite Structures for Constructing Superconducting and Magnetic Structures

IP.com Disclosure Number: IPCOM000119700D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 88K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR [+5]

Abstract

High Tc superconductors with critical temperatures > 77@K have been produced in composite mixtures with materials that provide mechanical strength where the basic superconducting properties are retained. In particular, these composite materials retain the ability to exclude a magnetic field causing, for example, the levitation of a magnet and magnetic shielding. Devices can be constructed using the composite by varying the superconducting fraction to arrive at desirable characteristics. We have, for example, produced composites with a variety of materials: silicon rubber, pliobond cement, vacuum grease, epoxies, such as Torr seal, crystal cast and stycast.

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Composite Structures for Constructing Superconducting and Magnetic
Structures

      High Tc superconductors with critical temperatures > 77@K
have been produced in composite mixtures with materials that provide
mechanical strength where the basic superconducting properties are
retained.  In particular, these composite materials retain the
ability to exclude a magnetic field causing, for example, the
levitation of a magnet and magnetic shielding.  Devices can be
constructed using the composite by varying the superconducting
fraction to arrive at desirable characteristics.  We have, for
example, produced composites with a variety of materials: silicon
rubber, pliobond cement, vacuum grease, epoxies, such as Torr seal,
crystal cast and stycast.  Mixtures of YBa2Cu3O7 in epoxy and other
polymer bonding materials are easily formed and hardened into shapes
that when cooled to below Tc exhibit magnetic field exclusion and
will, for example, levitate a magnet.
Composites of superconducting powders with various binders to produce
moldable, machinable and/or mechanically strong materials

      Mechanical devices and electrical devices formed from
composites of superconducting powder of the YyBabCucOo type (where
y,b,c,o are normally, but not limited to 1,2,3,7, respectively) can
be formed by pressing and sintering the powders.  These devices are
not mechanically strong and their superconducting properties
deteriorate with time (in normal atmosphere).

      The work described here is aimed at developing a process to
produce composites of these superconducting materials with binders
(i.e., epoxies) to improve the mechanical properties and/or the
durability of these devices.

      For the purpose of this discussion, the term "superconducting
properties" shall include a sharp reduction in resistivity at reduced
temperatures and/or the exclusion of external magnetic fields.
Composites of YBa2Cu3O7 powder with epoxies

      Powder of YBa2Cu3O7 was mixed with "Torr seal epoxy" (a Varian
Inc. product), "crystal cast", and "stycast".  Both stycast
composites and crystal cast composites made without powder cracked...