US 11,746,903 B2
Piston ring and method for manufacturing same
Akio Shinohara, Kashiwazaki (JP)
Appl. No. 17/996,433
Filed by KABUSHIKI KAISHA RIKEN, Tokyo (JP)
PCT Filed Dec. 8, 2021, PCT No. PCT/JP2021/045155
§ 371(c)(1), (2) Date Oct. 18, 2022,
PCT Pub. No. WO2022/209023, PCT Pub. Date Oct. 6, 2022.
Claims priority of application No. 2021-057342 (JP), filed on Mar. 30, 2021.
Prior Publication US 2023/0127883 A1, Apr. 27, 2023
Int. Cl. F16J 9/26 (2006.01); C23C 14/06 (2006.01); C23C 14/32 (2006.01)
CPC F16J 9/26 (2013.01) [C23C 14/0605 (2013.01); C23C 14/325 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A piston ring comprising:
a base material; and
a DLC film provided to cover at least a part of a surface of the base material,
wherein the DLC film has a hydrogen content of less than 5 atom %, an extinction coefficient of 0.1 to 0.4 as measured using light having a wavelength of 550 nm, and a nanoindentation hardness of 16 to 26 GPa.