Patent ID: 8722197

Claim:
Sliding contact part, adapted to operate in a lubricated regime, coated with a thin hard layer having a thickness no greater than 5 μm and a tribological function, wherein the thin layer is deposited by at least one of physical vapor deposition and plasma assisted chemical vapor deposition on a surface having a roughness profile, parameters and a mean period of the roughness profile of the surface prior to thin layer deposition being determined for improving tribological performance such that a ratio A between the square of the mean period of the profile (PSM) in μm and the roughness profile (Pa) in μm, as defined by French standard ISO 4288, is equal to or greater than 5×105 μm, that is: A = P SM 2 ≥ 5 × 10 5 ⁢ ⁢ µm P ⁢ ⁢ a , whereby equivalent or superior tribological performance is attained without the necessity of applying a high finish level to the surface.