Abstract: A wear layer is provided for each of a piston and cylinder of an internal combustion engine in which ash-producing fuels of solid-liquid mixtures are combusted. Each layer consists of a hard phase and a second phase of lower hardness and greater toughness. Each wear layer has a minimum thickness of one millimeter; the hard phase has a minimum hardness of 1900 HV with a mean chord length in the running direction of from 30 to 200 microns. There is a metallurgical bond between the phases in the wear layer as well as between the wear layer and the substrate. In addition, the hard phases of the respective wear layers have an almost equal hardness value.