DLC-COATED TOOL

摘要

A DLC-coated tool produced by forming a substantially hydrogen-free DLC film on a substrate, wherein the DLC film has a density of 3.0 to 3.4g/cm3 and a nanoindentation hardness of 40 to 100GPa and wherein in the surface scanning test with a stylus type surface profile measuring apparatus provided with a stylus whose point has a radius of curvature of 2µm at a measurement feed of 0.01mm, the ratio of the absolute value of a difference between the arithmetic mean surface roughness of the substrate before film formation and the arithmetic mean roughness of the DLC film to the thickness of the DLC film, ?Ra/t, is 0.05 or below and the ratio of the occupancy area ratio (s) of convexed and recessed parts of the DLC film due to the adhesion or desorption of foreign matter to the thickness (t) of the film, s/t, is 0.01 (%/nm) or below.