Abstract: A process for fabricating worked superconducting ceramic material of a mean grain size not more than 10 um is disclosed, which comprises the steps of: (a) preparing a metal casing containing a starting powder material having a composition for forming an oxide superconductor; (b) calcining the starting powder material contained in the casing at a temperature range of 850.degree. to 950.degree. C.; (c) subjecting said casing to a HIP treatment; (d) subjecting said casing containing hot deformed material to cold deformation processing; and (e) subjecting said casing to stress relief treatment by annealing in the presence of oxygen.

Abstract: Sialon-base ceramic materials having both high hardness and good sinterability and can show excellent wear resistance when used in cutting tools and other wear-resisting tools. A Sialon-base ceramic material according to the invention has main components consisting of .beta.-Sialon expressed by a chemical formula Si.sub.6-z Al.sub.z O.sub.z N.sub.8-z, z being larger than 0 but not more than 4.3, and .alpha.-Sialon expressed by a chemical formula M.sub.x (Si, Al).sub.12 (O,N).sub.16, x being larger than 0 but not more than 2, M representing at least one selected from the group consisting of Li, Na, Ca, Mg, Y, and any rare earth element, the ratio of the .alpha.-Sialon/the .beta.-Sialon being within a range from 25/75 to 95/5 in volume.