Abstract: A reactively combined silicon nitride is produced in which the starting material is pure silicon powder or a powder mixture of pure silicon and its nitride. This material is subjected to cold isostatic pressing or a slip casting or diecasting process before it is brought into a hot isostatic mold. The reaction is triggered under a nitrogen pressure of initially 0.5-2.0 MPa and at a starting temperature of 1000.degree. C. During the reaction the pressure is raised to 4.9 MPa and the temperature to at most 1420.degree. C. This raising of pressure and temperature is carried out at least partially stepwise. Obtained thereby is a product having a degree of nitriding greater than 92%. With a cycle time of less than 24 hours, the process permits molded articles to be produced which have a wall thickness of more than 10 mm, the material being uniformly nitrided.

Abstract: A pulsed infrared laser has an optical system for focusing the laser beam impulse, positioning a metallic workpiece to be drilled at the waist of the beam or at a spacing in the propagation direction in front of the waist of the laser beam, surrounding the portion of the workpiece from which metal is being removed with an atmosphere containing helium and/or hydrogen during the removal process, forming an expanding plasma in front of the portion of the workpiece to be drilled which absorbs the laser radiation at the start of the laser beam impulse by focusing the laser beam impulse at a large aperture angle and dimensioning the timewise intensity course of the laser beam impulse, and maintaining the expanding plasma only during a fraction of the laser beam impulse to remove material from the workpiece.