US 12,188,564 B2
Piston ring, and method for manufacturing same
Hiroki Saito, Kashiwazaki (JP); Keiji Honda, Kashiwazaki (JP); and Yuji Shima, Kashiwazaki (JP)
Appl. No. 17/793,654
Filed by KABUSHIKI KAISHA RIKEN, Tokyo (JP)
PCT Filed Jan. 21, 2021, PCT No. PCT/JP2021/002102
§ 371(c)(1), (2) Date Jul. 19, 2022,
PCT Pub. No. WO2021/153425, PCT Pub. Date Aug. 5, 2021.
Claims priority of application No. 2020-010754 (JP), filed on Jan. 27, 2020.
Prior Publication US 2023/0083774 A1, Mar. 16, 2023
Int. Cl. F16J 9/26 (2006.01); C23C 14/06 (2006.01)
CPC F16J 9/26 (2013.01) [C23C 14/0641 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A piston ring comprising:
a substrate; and
a film covering at least a part of a surface of the substrate,
wherein the film comprises Cr, Si and N, and
wherein:
a Si content of the film is in a range of 1.1 to 7.5 at %,
a crystallite size of the film is in a range of 10 to 30 nm, and
a compressive residual stress of the film is 400 to 800 MPa.