Coated cutting tool
A coated cutting tool, comprising: a substrate; and a coating layer formed on a surface of the substrate, wherein the coating layer includes a lower layer and an upper layer in this order from a substrate side toward a surface side, and the upper layer is formed on a surface of the lower layer, the lower layer contains a compound having a composition represented by (Al x Ti 1-x )N, an average thickness of the lower layer is 1.0 μm or more and 15.0 μm or less, the upper layer contains an α-Al 2 O 3 layer containing α-Al 2 O 3 , an average thickness of the upper layer is 0.5 μm or more and 15.0 μm or less, and in grains of the α-Al 2 O 3 layer, a proportion of grains of which a grain size is 0.05 μm or more and less than 0.5 μm is 50% by area or more and 80% by area or less.
1. A coated cutting tool, comprising:
a substrate; and
a coating layer formed on a surface of the substrate, wherein
the coating layer includes a lower layer and an upper layer in this order from a substrate side toward a surface side of the coating layer, and the upper layer is formed on a surface of the lower layer,
the lower layer contains a compound having a composition represented by Formula (1) below
(Al x Ti 1-x )N (1)
where, in Formula (1), x represents an atomic ratio of an Al element to a sum of the Al element and a Ti element, and 0.70≤x≤0.90 is satisfied,
an average thickness of the lower layer is 1.0 μm or more and 15.0 μm or less,
the upper layer contains an α-Al 2 O 3 layer containing α-Al 2 O 3 ,
an average thickness of the upper layer is 0.5 μm or more and 15.0 μm or less, and
in grains of the α-Al 2 O 3 layer, a proportion of grains of which a grain size is 0.05 μm or more and less than 0.5 μm is 50% by area or more and 80% by area or less.
2. The coated cutting tool according to claim 1 , wherein in the grains of the cl-Al 2 O 3 layer, a proportion of grains of which the grain size is 0.5 μm or more and less than 1.0 μm is 10% by area or more and 50% by area or less.
3. The coated cutting tool according to claim 1 , wherein in the grains of the α-Al 2 O 3 layer, a proportion of grains of which the grain size is 1.0 μm or more and 3.0 μm or less is 0% by area or more and 10% by area or less.
4. The coated cutting tool according to claim 1 , wherein, in the upper layer, a proportion of length of a Σ3 grain boundary to 100% of a total length of all grain boundaries is 0% or more and 10% or less.
5. The coated cutting tool according to claim 1 , wherein an average thickness of the entire coating layer is 2.0 μm or more and 20.0 μm or less.
6. The coated cutting tool according to claim 1 , wherein the substrate is any of a cemented carbide, a cermet, a ceramic, or a cubic boron nitride sintered body.
7. The coated cutting tool according to claim 2 , wherein in the grains of the α-Al 2 O 3 layer, a proportion of grains of which the grain size is 1.0 μm or more and 3.0 μm or less is 0% by area or more and 10% by area or less.
8. The coated cutting tool according to claim 2 , wherein, in the upper layer, a proportion of length of a Σ3 grain boundary to 100% of a total length of all grain boundaries is 0% or more and 10% or less.
9. The coated cutting tool according to claim 3 , wherein, in the upper layer, a proportion of length of a Σ3 grain boundary to 100% of a total length of all grain boundaries is 0% or more and 10% or less.
10. The coated cutting tool according to claim 7 , wherein, in the upper layer, a proportion of length of a Σ3 grain boundary to 100% of a total length of all grain boundaries is 0% or more and 10% or less.
11. The coated cutting tool according to claim 2 , wherein an average thickness of the entire coating layer is 2.0 μm or more and 20.0 μm or less.
12. The coated cutting tool according to claim 3 , wherein an average thickness of the entire coating layer is 2.0 μm or more and 20.0 μm or less.
13. The coated cutting tool according to claim 4 , wherein an average thickness of the entire coating layer is 2.0 μm or more and 20.0 μm or less.
14. The coated cutting tool according to claim 7 , wherein an average thickness of the entire coating layer is 2.0 μm or more and 20.0 μm or less.
15. The coated cutting tool according to claim 8 , wherein an average thickness of the entire coating layer is 2.0 μm or more and 20.0 μm or less.
16. The coated cutting tool according to claim 9 , wherein an average thickness of the entire coating layer is 2.0 μm or more and 20.0 μm or less.
17. The coated cutting tool according to claim 10 , wherein an average thickness of the entire coating layer is 2.0 μm or more and 20.0 μm or less.
18. The coated cutting tool according to claim 2 , wherein the substrate is any of a cemented carbide, a cermet, a ceramic, or a cubic boron nitride sintered body.
19. The coated cutting tool according to claim 3 , wherein the substrate is any of a cemented carbide, a cermet, a ceramic, or a cubic boron nitride sintered body.
20. The coated cutting tool according to claim 4 , wherein the substrate is any of a cemented carbide, a cermet, a ceramic, or a cubic boron nitride sintered body.