| abstract |
The present invention relates to a system wherein a pair of relatively movable, facing DLC contact surfaces at least one of which is coated with a DLC film, are further lowered in friction, and the low friction property is stably maintained. The present invention also relates to a lubricant for the system, and a lubricating method. The lubricant for the system having the DLC contact surfaces contains lubricant base oil (A) mainly composed of base oil (X), and sulfur-containing molybdenum complex (B). The base oil (X) is at least one of hydrocracked mineral oils, wax-isomerized mineral oils, and poly-α-olefin base oils, and has a kinematic viscosity of 2 to 20 mm 2 /s at 100° C., a total aromatic content of not higher than 5 mass %, and a total sulfur content of not higher than 0.005 mass %. |