The invention relates to a process for coating a substrate composed of cemented carbide, a cermet, steel or ceramic with at least one Ti1-xAlxN layer by means of a DC sputtering process. The invention further relates to a workpiece or tool which has been coated by the above-described process and to the use thereof. It is an object of the present invention to provide a process by means of which it is possible to produce coatings which combine the advantages of the sputtering process and the arc process, i.e. to make it possible to obtain a coating which has a low roughness and an advantageous (200) texture. A further object of the present invention is to provide a workpiece which has a coating having the properties mentioned. A further object of the present invention is to use tools which are particularly suitable for machining metals. The object achieved by the process is distinguished by ionization aids being used for increasing the plasma densities.