Nippon Piston Ring Co., Ltd.

Noriaki Chida

Masataka Okano

Shota Seki

To provide a sliding member, such as a piston ring for an internal combustion engine, having low friction and excellent toughness. The above-described problem is solved by a sliding member () such as a piston ring coated with a Cr&#x2014;B&#x2014;Ti&#x2014;V&#x2014;(Mn, Mo)&#x2014;N-based alloy film () on a sliding surface () thereof, and configured so that the alloy film () contains one or both of Mn and Mo and has a total content of the Mn and the Mo within a range of 2 mass % or less. Preferably, a B content is within a range of 0.1 mass % to 1.5 mass %, inclusive, a V content is within a range of 0.05 mass % to 1 mass %, inclusive, and a Ti content is within a range of 0.05 mass % to 1.5 mass %, inclusive.

Sliding member

Provided is a piston ring () comprising a sliding surface () covered with a Cr&#x2014;B&#x2014;V&#x2014;N alloy film (), 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 () having higher wear resistance, cracking resistance, and peeling resistance. This alloy film () preferably further includes Ti, the Ti content being within a range greater than 0 mass % and 8 mass % or less. Such a piston ring () is preferably mounted on an engine that uses an alcohol fuel or an alcohol-containing fuel.

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Ichinoseki, Japan

Noriaki Chida