Abstract: A diamond coating includes a first diamond layer made of minute diamond particles and a second diamond layer made of coarse diamond particles: in a flank-face side diamond coating, a mean coat thickness d2 is not less than 3 ?m and not more than 25 ?m, a first diamond layer is formed on a surface side and a second diamond layer is formed on a tool base side: a rake-face side diamond coating is in a smaller range of 50 ?m or 1/10 of a tool diameter from a tip of a base cutting-edge part; in the rake-face side diamond coating, a mean coat thickness d1 is a smaller one in a range not less than 0 ?m and not more than 5.0 ?m or a range less than d2: and a boundary part between the first diamond layer and the second diamond layer.

Abstract: A diamond coating includes a first diamond layer made of minute diamond particles and a second diamond layer made of coarse diamond particles: in a flank-face side diamond coating, a mean coat thickness d2 is not less than 3 ?m and not more than 25 ?m, a first diamond layer is formed on a surface side and a second diamond layer is formed on a tool base side: a rake-face side diamond coating is in a smaller range of 50 ?m or 1/10 of a tool diameter from a tip of a base cutting-edge part; in the rake-face side diamond coating, a mean coat thickness d1 is a smaller one in a range not less than 0 ?m and not more than 5.0 ?m or a range less than d2: and a boundary part between the first diamond layer and the second diamond layer.

Abstract: In this diamond-coated cemented carbide cutting tool, (1) an average particle size of WC particles is 0.5 to 0.9 ?m, (2) (Rz) being 0.5 to 1.0 ?m, a maximum distance between the concave and convex (?) is 0.5 to 1.5 ?m, a length (Ye) is 0.5 to 2.0 ?m, (3) a sum of areas of WC particles, which satisfies (L1) being 0.4 to 0.8 ?m, (L2) being 0.2 to 0.4 ?m, and (L1)/(L2) being 1.5 to 2.5, is 70 area % or more, (4) an average grain size of diamond crystals in a region of 0.5 to 1.5 ?m from the body interface is 0.1 to 0.3 ?m, and (5) columnar crystals satisfying at least one of: a ratio of crystals, which has a growth direction shifted in 10 degrees or less from the diamond film thickness direction, being 90% or more; or an orientation ratio of <110> being 30 to 70%.

Abstract: In this diamond-coated cemented carbide cutting tool, (1) an average particle size of WC particles is 0.5 to 0.9 ?m, (2) (Rz) being 0.5 to 1.0 ?m, a maximum distance between the concave and convex (?) is 0.5 to 1.5 ?m, a length (Ye) is 0.5 to 2.0 ?m, (3) a sum of areas of WC particles, which satisfies (L1) being 0.4 to 0.8 ?m, (L2) being 0.2 to 0.4 ?m, and (L1)/(L2) being 1.5 to 2.5, is 70 area % or more, (4) an average grain size of diamond crystals in a region of 0.5 to 1.5 ?m from the body interface is 0.1 to 0.3 ?m, and (5) columnar crystals satisfying at least one of: a ratio of crystals, which has a growth direction shifted in 10 degrees or less from the diamond film thickness direction, being 90% or more; or an orientation ratio of <110> being 30 to 70%.