Piston ring

The present invention relates to a piston ring (1) for internal combustion engines provided with a base comprising a sliding external surface (3), an internal surface (4), an upper surface (5), and alower surface (6), the external surface (3) comprising chamfered edges (7, 8), the external (3), internal (4), upper (5), and lower (6) surfaces and the chamfered edges (7, 8) of the ring (1) comprising a first, nitrided layer (10), the first layer (10) comprising a thickness of between 30 and 70 microns on the upper (5) and lower (6) surfaces and a thickness of up to 7microns on the external surface (3) and on the chamfered edges (7, 8), the external surface (3) and the chamfered edges (7, 8) comprising a sliding layer (11) composed of a hard chromium or ceramic chromium plated coating, the sliding layer (11) being applied on the first layer (10), the sliding layer (11) comprising a thickness of between 80 and 175 microns, guaranteeing a high level of durability of the ring (1) owing to the excellent wear-resista