Coated cutting tool
A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, the coating layer including at least one α-type aluminum oxide layer, wherein, in the α-type aluminum oxide layer, a texture coefficient TC (1,1,9) of a (1,1,9) plane is 1.4 or more. TC ( 1 , 1 , 9 ) = I ( 1 , 1 , 9 ) I 0 ( 1 , 1 , 9 ) { 1 8 ∑ I ( h , k , l ) I 0 ( h , k , l ) } - 1 ( 1 ) (In formula (1), I (h,k,l) denotes a peak intensity for an (h,k,l) plane in X-ray diffraction of the α-type aluminum oxide layer, I 0 (h,k,l) denotes a standard diffraction intensity for an (h,k,l) plane which is indicated on a JCPDS Card No. 10-0173 for α-type aluminum oxide, and (h,k,l) refers to eight crystal planes of (0,1,2), (1,0,4), (1,1,0), (1,1,3), (0,2,4), (1,1,6), (2,1,4) and (1,1,9).).
1. A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, the coating layer including at least one α-type aluminum oxide layer, wherein, in the α-type aluminum oxide layer, a texture coefficient TC (1,1,9) of a (1,1,9) plane represented by formula (1) below is 1.4 or more,
TC
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1
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1
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9
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I
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{
1
8
∑
I
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h
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k
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I
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1
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(In formula (1), I (h,k,l) denotes a peak intensity for an (h,k,l) plane in X-ray diffraction of the α-type aluminum oxide layer, I 0 (h,k,l) denotes a standard diffraction intensity for an (h,k,l) plane which is indicated on a JCPDS Card No. 10-0173 for α-type aluminum oxide, and (h,k,l) refers to eight crystal planes of (0,1,2), (1,0,4), (1,1,0), (1,1,3), (0,2,4), (1,1,6), (2,1,4) and (1,1,9)).
2. The coated cutting tool according to claim 1 , wherein, in the α-type aluminum oxide layer, the texture coefficient TC (1,1,9) is from 2.0 or more to 7.2 or less.
3. The coated cutting tool according to claim 1 , wherein a residual stress in a (1,1,6) plane of the α-type aluminum oxide layer is, in at least part thereof, from −300 MPa or higher to 300 MPa or lower.
4. The coated cutting tool according to claim 1 , wherein an average particle size of the α-type aluminum oxide layer is from 0.1 μm or more to 3.0 μm or less.
5. The coated cutting tool according to claim 1 , wherein an average thickness of the α-type aluminum oxide layer is from 1.0 μm or more to 15.0 μm or less.
6. The coated cutting tool according to claim 1 , wherein the coating layer comprises a TiCN layer between the substrate and the α-type aluminum oxide layer, and an average thickness of the TiCN layer is from 2.0 μm or more to 20.0 μm or less.
7. The coated cutting tool according to claim 6 , wherein the coating layer comprises, between the TiCN layer and the α-type aluminum oxide layer, an intermediate layer comprised of a compound of at least one kind selected from the group consisting of a Ti carbonate, a Ti oxynitride and a Ti carboxynitride.
8. The coated cutting tool according to claim 1 , wherein an average thickness of the coating layer is from 3.0 μm or more to 30.0 μm or less.
9. The coated cutting tool according to claim 1 , wherein the coating layer comprises a TiN layer as an outermost layer on a side opposite to the substrate.
10. The coated cutting tool according to claim 1 , wherein the substrate is comprised of any of a cemented carbide, cermet, ceramics and a sintered body containing cubic boron nitride.
11. The coated cutting tool according to claim 2 , wherein a residual stress value in a (1,1,6) plane of the α-type aluminum oxide layer is, in at least part thereof, from −300 MPa or higher to 300 MPa or lower.
12. The coated cutting tool according to claim 2 , wherein an average particle size of the α-type aluminum oxide layer is from 0.1 μm or more to 3.0 μm or less.
13. The coated cutting tool according to claim 3 , wherein an average particle size of the α-type aluminum oxide layer is from 0.1 μm or more to 3.0 μm or less.
14. The coated cutting tool according to claim 2 , wherein an average thickness of the α-type aluminum oxide layer is from 1.0 μm or more to 15.0 μm or less.
15. The coated cutting tool according to claim 3 , wherein an average thickness of the α-type aluminum oxide layer is from 1.0 μm or more to 15.0 μm or less.
16. The coated cutting tool according to claim 4 , wherein an average thickness of the α-type aluminum oxide layer is from 1.0 μm or more to 15.0 μm or less.
17. The coated cutting tool according to claim 2 , wherein the coating layer comprises a TiCN layer between the substrate and the α-type aluminum oxide layer, and an average thickness of the TiCN layer is from 2.0 μm or more to 20.0 μm or less.
18. The coated cutting tool according to claim 3 , wherein the coating layer comprises a TiCN layer between the substrate and the α-type aluminum oxide layer, and an average thickness of the TiCN layer is from 2.0 μm or more to 20.0 μm or less.
19. The coated cutting tool according to claim 4 , wherein the coating layer comprises a TiCN layer between the substrate and the α-type aluminum oxide layer, and an average thickness of the TiCN layer is from 2.0 μm or more to 20.0 μm or less.
20. The coated cutting tool according to claim 5 , wherein the coating layer comprises a TiCN layer between the substrate and the α-type aluminum oxide layer, and an average thickness of the TiCN layer is from 2.0 μm or more to 20.0 μm or less.