| 摘要 |
Provided is a surface-coated cutting tool which has therein a hard coating layer capable of exhibiting excellent chipping resistance during the high-speed intermittent cutting work of an alloy steel or the like. A surface-coated cutting tool, in which the surface of a base comprising a WC-based cemented carbide, a TiCN-based cermet and an ultrahigh-pressure-sintered cBN-based compact is coated with at least a (Ti1-XAlX)(CYN1-Y) layer (wherein X and Y independently represent an atomic ratio and fulfill the formulae 0.60 <= X <= 0.90 and 0.0005 <= Y <= 0.005, respectively) that has a cubic structure and is formed by, for example, a chemical deposition method using Al(CH3)3 as a reaction gas component, wherein the amount of Al (XL) is 0.55 to 0.70 inclusive (i.e., 0.55 <= XL <= 0.70) and the average grain diameter (DL) of (Ti1-XAlX)(CYN1-Y) crystal grains is 0.1 mum or less in a region of a composite carbonitride layer which is adjacent to the interface between the base and the composite carbonitride layer, the amount of Al (XH) is 0.80 to 0.95 inclusive (i.e., 0.80 <= XH <= 0.95) and the average grain diameter (DH) of the (Ti1-XAlX)(CYN1-Y) crystal grains is 0.5 to 2 mum in a region of the composite carbonitride layer which is adjacent to the surface of the composite carbonitride layer, the content ratio of Al in the composite carbonitride layer is gradually increased toward the front surface layer side of the composite carbonitride layer, and the average grain diameter of the (Ti1-XAlX)(CYN1-Y) crystal grains is gradually increased toward the front surface layer side of the composite carbonitride layer. |
