Abstract: A compression ring, has a ring running surface (2) on a first butt end region, a ring running surface (2?) on a second butt end region, a ring inner surface (4), a top ring flank surface (6) and a bottom ring flank surface (8), wherein the ring has overlapping first and second butt end regions. The first butt end region has at least one protrusion (10) in the circumferential direction, and the second butt end region has at least one recess (12) in the circumferential direction. The at least one protrusion (10) forms at least one axial and/or radial overlap surface, and the at least one recess (12) forms at least one parallel surface, which lies at least partially opposite to the axial and/or radial overlap surface in order to shift parallel to one another in response to a change of the butt play. At least one of the surfaces, which can be shifted parallel to one another, is provided with an axial wear element (14) and/or with a radial wear element (14?).

Abstract: A coated piston ring having a base body of chromium steel with more than 10 wt.-% chromium and having an inner circumferential surface, a first flank surface, a second flank surface and an outer circumferential surface. The first flank surface comprises a nitride diffusion layer with a layer thickness of from 5-300 ?m, a nitride connecting layer with a layer thickness of from 0.5-15 ?m on the nitride diffusion layer, and an oxide layer with a layer thickness of from 0.05-3 ?m on the nitride connecting layer. The second flank surface comprises the nitride diffusion layer, and the outer circumferential surface comprises the nitride diffusion layer and a chromium solid particle layer with 0.1-30 vol.-% solid particles, relative to the total volume of the chromium solid particle layer on the nitride diffusion layer.

Abstract: A structured chromium solids particles layer with a network of cracks in which solids particles are embedded, wherein the crack density is 10-250 per mm, the particle size of the solids particles lies in the range of from 0.01-10 ?m, the proportion of solids particles in the overall layer is 1-30 vol.-% and the chromium solids particles layer has a microstructure with depressions in the surface of the layer, wherein the proportion of the surface area accounted for by the depressions is 5-80%. A method for producing the structured chromium solids particles layer on a workpiece includes introducing the workpiece into an electrolyte containing a Cr(VI) compound and electrolytically depositing a chromium layer at a current density of 20-100 A/dm2 and a current yield of 12% or less and then reversing the current direction wherein the solid particles are embedded within the network of cracks.

Abstract: A structured chromium solids particles layer with a network of cracks in which solids particles are embedded, wherein the crack density is 10-250 per mm, the particle size of the solids particles lies in the range of from 0.01-10 ?m, the proportion of solids particles in the overall layer is 1-30 vol.-% and the chromium solids particles layer has a microstructure with depressions in the surface of the layer, wherein the proportion of the surface area accounted for by the depressions is 5-80%. A method for producing the structured chromium solids particles layer on a workpiece includes introducing the workpiece into an electrolyte containing a Cr(VI) compound and electrolytically depositing a chromium layer at a current density of 20-100 A/dm2 and a current yield of 12% or less and then reversing the current direction wherein the solid particles are embedded within the network of cracks.