| 摘要 |
A surface-coated cutting tool of the present invention includes: a cutting tool body; and a hard coating layer provided on a surface of the cutting tool body, in which the hard coating layer includes a complex nitride or carbonitride layer, which is expressed by a composition formula: (Ti1-xAlx)(CyN1-y), the average content ratio Xavg of Al and the average content ratio Yavg of C in the complex nitride or carbonitride layer satisfy 0.60≦Xavg≦0.95 and 0≦Yavg≦0.005, provided that each of Xavg and Yavg is in atomic ratio, the complex nitride or carbonitride layer includes crystal grains with a cubic structure, and in the crystal grains with the cubic structure, a composition of Ti and Al is periodically changed in a direction of the normal line to the surface of the cutting tool body. |
| 主权项 |
1. A surface-coated cutting tool comprising:
a cutting tool body made of any one of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, and cubic boron nitride-based ultra-high pressure sintered material; and a hard coating layer provided on a surface of the cutting tool body, wherein (a) the hard coating layer comprises at least a Ti and Al complex nitride or carbonitride layer, which is formed by a chemical vapor deposition method and has an average layer thickness of 1 to 20 μm, in a case where a composition of the complex nitride or carbonitride layer is expressed by a composition formula: (Ti1-xAlx)(CyN1-y), an average content ratio Xavg, which is a ratio of Al to a total amount of Ti and Al in the complex nitride or carbonitride layer; and an average content ratio Yavg, which is a ratio of C to a total amount of C and N in the complex nitride or carbonitride layer, satisfy 0.60≦Xavg≦0.95 and 0≦Yavg≦0.005, provided that each of Xavg and Yavg is in atomic ratio, (b) the complex nitride or carbonitride layer includes at least a phase constituted by complex nitride or complex carbonitride with a NaCl type face-centered cubic structure, (c) regarding the complex nitride or carbonitride layer, in a case where a crystal orientation of each of crystal grains with the NaCl type face-centered cubic structure in the complex nitride or carbonitride layer is analyzed from a vertical section direction of the complex nitride or carbonitride layer using an electron backscatter diffraction apparatus: in an inclination angle frequency distribution, the highest peak exists in an inclination angle division in a range of 0° to 10° and the sum of frequencies in the range of 0° to 10° is 35% or more to the total frequencies in the inclination angle frequency distribution, the inclination angle frequency distribution being obtained by measuring inclination angles between a direction of the normal line to the surface of the cutting tool body and the normal lines to {100} planes as a crystal plane of the crystal grains, dividing inclination angles belonging to a range of 0° to 45° among the measured inclination angles every pitch of 0.25°, and counting the frequencies in each division, (d) in the direction of the normal line to the surface of the cutting tool body: a periodic composition change of Ti and Al in the composition formula: (Ti1-xAlx)(CyN1-y) exists in each of the crystal grains with the NaCl type face-centered cubic structure in the complex nitride or carbonitride layer; and a difference Δx obtained by subtracting an average of local minimum values from an average of local maximum values of x in the periodic composition change is 0.03 to 0.25, and (e) in the crystal grains with the NaCl type face-centered cubic structure having the periodic composition change of Ti and Al in the complex nitride or carbonitride layer, a period of the periodic composition change in the direction of the normal line to the surface of the cutting tool body is 3 to 100 nm. |
