Abstract: A powder-in-tube method is disclosed for making a composite superconducting oxide wire which comprises loading a copper tube with a mixture composed of rare earth metal oxide, BaO.sub.2 and copper oxide or the finished superconductor powder and subjecting the loaded tube to drawing and a heat treatment at a temperature of up to 950.degree. C., wherein prior to loading the copper tube, the tube is oxidized at least on its inside to form a copper oxide layer having a thickness of 1 to 100 .mu.m and then a silver intermediate layer is inserted to the oxidized copper tube.

Abstract: Production of a sheathed wire or multiple-filament conductor composed of ceramic high-temperature superconductor by mixing Y.sub.2 O.sub.3, CuO and BaO.sub.2 or BaO.sub.2 +BaO, loading the powder mixture (3) into the interior of a metal sheath (1) lined with Ag intermediate layer (2), slowly heating to a maximum permissible reaction/sintering temperature of 950.degree. C. in a period of at least 0.1 h, holding the sintering temperature for at least 1 h, cooling down to 200.degree. C. at at most 10.degree. to 100.degree. C./h to form a conducting core (4) composed of YBa.sub.2 Cu.sub.3 O.sub.6.5-7.5. Variants having a layer composed of CuO, diffusion barrier composed of Ni, Ta, Nb, V or having Ag intermediate layer doped with AgO or BaO.sub.2. Preferably reactive sintering under a pressure of 10 to 10.000 bar as hot isostatic pressing. Variant: reactive annealing of the powder mixture under oxygen pressure of 10 to 3000 bar at 600.degree. to 950.degree. C.

Abstract: A tool for isothermal forging is disclosed. The tool consists of two die halves, at least one of which consists of an assembly of individual components whose side facing the workpiece is provided with a thin electrically insulating layer. The assembly of the die half from individual components occurs following forming of the components by casting and/or forging, and machining of the formed components. The forming of the die halves from separate components makes it possible to adapt the components of the die half to the particular working conditions in an optimum manner. The provision of an insulating layer on the individual components reduces the risk of local welding and nonuniform temperature distribution during inductive heating.