Piston ring with oxide-nitride composite layer

摘要

A piston ring for use in a cylinder of an internal combustion engine, which ring is nitride-hardened at least on the sliding surface between piston ring and cylinder wall. The nitride layer is composed of a precipitated layer and a compound layer, wherein the piston ring consists of a low-alloyed iron-base material and an oxide layer is deposited on the compound layer.