Abstract: A method is for simultaneously cutting off a multiplicity of wafers from a hard, brittle workpiece which has a longitudinal axis and a peripheral surface. The workpiece is guided, by means of a translational relative movement, directed perpendicular to the longitudinal axis, between the workpiece and a wire web of a wire saw with the aid of a feed device, through the wire web which is formed by a sawing wire. The workpiece is rotated about the longitudinal axis while the wafers are being cut off. There is also a wire saw which is suitable for carrying out the method and has a device for holding and for rotating the workpiece about the longitudinal axis.

Abstract: Dense sintered bodies are provided whicha) comprise from 45 to 99.5 wt % of SiC, the SiC being present in the sintered body as a crystalline first phase, andb) comprise from 0.5 to 55 wt % of a sintering aid, from 0.5 to 30 wt % of which is selected from the group consisting of reaction products of Al.sub.2 O.sub.3 with Y.sub.2 O.sub.3, mixtures of at least one nitrogen-containing aluminum compound with reaction products of Al.sub.2 O.sub.3 with Y.sub.2 O.sub.3, mixtures of at least one rare earth oxide with at least one nitrogen-containing aluminum compound and/or Al.sub.2 O.sub.3, and from 0 to 25 wt % of which is selected from the group of the nitridic silicon compounds, the sintering aid being present in the sintered body as a second phase and optionally further phases, wherein the second phase and optionally the further phases are either amorphous to an extent of more than 10% or are present in amorphous form at the interface to the first phase to a width of at least .gtoreq.5 .ANG.

Abstract: A runner is provided which consists of a radial turbine ceramic rotor with an integrated ceramic shaft and a non-ceramic compressor impeller which are connected by a releasable, thermally and mechanically loadable mechanical coupling in such a way that the releasable mechanical coupling is located with the compressor impeller. This coupling consists of a cylindrical slotted sleeve which, on the one hand, is fitted into a cylindrical fitting bore in the compressor impeller and, on the other hand, accepts the end of the ceramic shaft in a fitting bore. In addition, the coupling has a tie rod with a screw thread and a pair of conical clamping elements between the cylindrical sleeve and the compressor impeller.