High-temperature porous-ceramic superconductors

A method for producing a porous, high-temperature ceramic body having superconductive properties when the body is subjected to liquid nitrogen, comprising the steps of:

• (a) mixing together powders in a stoichiometric ratio constituting the essential components of a copper-oxide composition capable of forming a ceramic having high-temperature superconductive properties at liquid nitrogen temperatures to provide a stock mixture:
• (b) firing the stock mixture in a crucible to produce a sintered clinker, and grinding the clinker to provide fine particles;
• (c) intermixing the particles with celluloxic fibers to form a master mixture which is then compressed at a pressure sufficient to crush the fibers therein to form fiber-reinforced green pellets, the amount of fibers being sufficient to produce the channels called for in the next step;
• (d) firing the pellets in air in a furnace at a temperature of about 400.degree. C. and for an initial period sufficient to cause the fibers therein to burn out and lose their identity to define interlaced diffusion channels in the pellets;
• and
• (e) continuing to fire the pellets in the furnace in flowing oxygen at an elevated temperature exceeding about 900.degree. for a final period sufficient to cause the compressed particles to sinter together to produce a porous ceramic body, during which period the oxygen diffuses through the channels to react and integrate with the interior of the body, whereby the resultant body is superconductive throughout its structure.