Processing method for superconducting ceramics
AssigneeThe United States of America as represented by the United States Department of Energy
InventorsIra D. Bloom, Roger B. Poeppel, Brian K. Flandermeyer
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Abstract
A process for preparing a superconducting ceramic and particularly YBa.sub.2 Cu.sub.3 O.sub.7-.delta., where .delta. is in the order of about 0.1-0.4, is carried out using a polymeric binder which decomposes below its ignition point to reduce carbon residue between the grains of the sintered ceramic and a nonhydroxylic organic solvent to limit the problems with water or certain alcohols on the ceramic composition.
Claims4
A method of preparing a sintered, metal-oxide superconducting ceramic of the formula YBa.sub.2 Cu.sub.3 O.sub.7-.delta. where .delta. is in the range of about 0.1-0.4, the method comprising the steps of
- calcining a mixture of reactants at a temperature sufficient to produce the unsintered ceramic,
- distributing a polymeric binder of polyisobutylene or polyisoprene and solvent throughout the unsintered ceramic, the binder being decomposable without forming a residue at temperatures below its ignition point, the solvent being a nonhydroxylic or organic solvent with a volatilization temperature below about 100.degree. C., grinding the unsintered composition including binder to reduce the particle size to about 5-10 microns, and
- heating the binder and unsintered ceramic to a sintering temperature above the ignition temperature, the heating being carried out under conditions to allow decomposition of the binder and removal of the decomposition products by volatilization prior to the sintering.
Dependencies are inferred from the claim text.