Piston ring

An internal combustion engine comprising at least one piston ring including a base having a sliding external surface, an internal surface, an upper surface, and a lower surface, the external surface having chamfered edges;

• wherein the external surface, the internal surface, the upper surface, the lower surface, and the chamfered edges have a coating with a nitrided first layer provided directly thereon, wherein a thickness of the first layer on the upper surface and the lower surface is greater than 0% up to 2% of a nominal axial thickness of the ring, and a thickness of the first layer on the external surface and the chamfered edges is greater than 0% up to 10% of the thickness of the first layer on the upper surface and the lower surface;
• and
• wherein the external surface and the chamfered edges include a sliding layer having one of a hard chromium or ceramic chromium plated coating, the sliding layer being applied on the first layer, the sliding layer having a thickness of between 80 and 175 microns.