Piston ring and manufacturing method therefor

Abstract

To provide a piston ring comprising a hard carbon film that is easy to form and exhibits excellent adhesion and wear resistance, and a manufacturing method therefor. The above-described problem is solved by means of a piston ring comprising a hard carbon filmformed on at least an outer peripheral sliding surfaceof a piston ring base material, wherein the hard carbon filmis a laminated film comprising a plurality of layers, including an upper layerwith a lamination pitch within a range of 3 nm to 50 nm inclusive, a middle layerwith a lamination pitch less than that of the upper layer, and a lower layerwith a lamination pitch within the same range as that of the upper layerand greater than that of the middle layer. This hard carbon filmmay be configured to have an spcomponent ratio within a range of 35% to 80% inclusive, measured in a TEM-EELS spectrum formed by combining electron energy loss spectroscopy (EELS) with a transmission electron microscope (TEM), and a hydrogen content within a range of 0.1 atom % to 5 atom % inclusive.