Patent ID: 7951756

Claim:
A system having diamond-like carbon (DLC) contact surfaces, comprising: a pair of relatively movable, facing DLC contact surfaces at least one of which is coated with a film of at least one of a-C (amorphous carbon) DLC and a-C:H (hydrogenated amorphous carbon) DLC, and a lubricant (L) interposed between said DLC contact surfaces, said lubricant (L) comprising: a lubricant base oil (A) containing a base oil (X) as a main component, a 0.001 to 0.2 mass % molybdenum dithiocarbamate as a sulfur-containing molybdenum complex (B) in terms of molybdenum elements, at least one friction modifier (C) selected from C1-C40 esters of aliphatic monocarboxylic acids, and a sulfur-free metal detergent (D) selected from alkali metal or alkaline earth metal salicylates, wherein said base oil (X) consists at least one of a hydrocracked mineral oil, a wax-isomerized mineral oil, and a poly-α-olefin base oil, and has a kinematic viscosity of 3.5 to 5 mm 2 /s at 100° C., a total aromatic content of 0 to 2 mass %, and a total sulfur content of not higher than 0.002 mass % wherein a content of said friction modifier (C) is 0.05 to 3.0 mass %, and a content of said sulfur-free metal detergent (D) is 0.01 to 1 mass % in terms of metal elements, based on a total amount of said lubricant (L).