PURPOSE: To improve the adhesion of the base of the base metal of a tool and a hard carbon film by coating the base metal with W, bringing an excited carbon-contg. gas into contact with it to form porous WC and thereafter coating it with a hard carbon film having small grain diameter.
CONSTITUTION: The surface of the base metal of the tool of WC sintered hard alloy is coated with metallic W into about 1 to 3μm thickness. An excited carbon-cong. gas is brought into contact with the coated metallic W to form porous WC having ≥0.1μm average grain diameter as a substrate. The substrate is coated with a hard carbon film having average grain diameter smaller than that of the porous WC by using a vapor phase synthesis method. In this way, the prevention of the diffusion of Co on the surface of the base metal can be attained, by which the hard carbon film coated sintered hard alloy tool in which the adhesion of the base metal and hard carbon film is excellent can be obtd.
SATO TOSHIKI
IKEDA TSUTOMU
