Abstract: Provided is a piston ring (10) comprising a sliding surface (11) covered with a Cr—B—V—N alloy film (3), wherein a B content is within a range of 0.1-1.5 mass % inclusive, a V content is within a range of 0.05-1 mass % inclusive, and a ratio [B content/V content] is within a range greater than 1 and 30 or less, thereby achieving a piston ring (10) having higher wear resistance, cracking resistance, and peeling resistance. This alloy film (3) preferably further includes Ti, the Ti content being within a range greater than 0 mass % and 8 mass % or less. Such a piston ring (10) is preferably mounted on an engine that uses an alcohol fuel or an alcohol-containing fuel.

Abstract: Provided is a piston ring (10) comprising a sliding surface (11) covered with a Cr—B—V—N alloy film (3), wherein a B content is within a range of 0.1-1.5 mass % inclusive, a V content is within a range of 0.05-1 mass % inclusive, and a ratio [B content/V content] is within a range greater than 1 and 30 or less, thereby achieving a piston ring (10) having higher wear resistance, cracking resistance, and peeling resistance. This alloy film (3) preferably further includes Ti, the Ti content being within a range greater than 0 mass % and 8 mass % or less. Such a piston ring (10) is preferably mounted on an engine that uses an alcohol fuel or an alcohol-containing fuel.