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 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 method for producing a structured hard chromium layer, during which chromium from an electrolyte is deposited onto a workpiece, which contains: a) a Cr(VI) compound in a quantity corresponding to between 50 and 300 g/l of chromic anhydride; b) 0.5 g/l to 10 g/l sulfuric acid, and; c) 5 g/l to 15 g/l aliphatic sulfonic acid having 1 to 6 carbon atoms. The electrolyte comprises substantially no compounds from the group consisting of ammonium molybdate, alkaline molybdate, alkaline earth molybdate, ammonium vanadate, alkaline vanadate and alkaline earth vanadate, ammonium zirconate, alkaline zirconate and alkaline earth zirconate, and is processed with a cathodic efficiency of 12% or less. A method for producing a coating, to a structured hard chromium layer, a coating and an electrolyte.

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.