Cutting tools
A cutting tool comprising a base material and a coating; wherein: the coating comprises a titanium compound layer and an α-Al 2 O 3 layer; the α-Al 2 O 3 layer comprises a region A 1 and a region A 2 ; the titanium compound layer comprises a region B 1 and a region B 2 ; an average particle diameter a1 of the α-Al 2 O 3 particles in the region A 1 , an average particle diameter a2 of the α-Al 2 O 3 particles in the region A 2 , an average particle diameter b1 of the titanium compound particles in the region B 1 , and an average particle diameter b2 of the titanium compound particles in the region B 2 satisfy relationships represented by respective expressions 1 to 3: 0.80≤ a 2/ b 2≤1.27 Expression 1 1.50≤ a 1/ a 2≤10 Expression 2 1.45≤ b 1/ b 2≤5 Expression 3 ; and the average particle diameter b1 is 0.10 μm or more and 0.50 μm or less.
1 . A cutting tool comprising a base material and a coating arranged on the base material; wherein:
the coating comprises a titanium compound layer arranged on the base material and an α-Al 2 O 3 layer arranged directly on the titanium compound layer;
the α-Al 2 O 3 layer is composed of a plurality of aα-Al 2 O 3 particles;
the α-Al 2 O 3 layer comprises a region A 1 and a region A 2 ;
the region A 1 is a region sandwiched between an imaginary plane SA 2 , which is located at a distance of 0.5 μm from an interface P 1 between the titanium compound layer and the α-Al 2 O 3 layer toward the surface side of the coating, and an imaginary plane SA 3 , which is located at a distance of 1.0 μm from the interface P 1 toward the surface side of the coating;
the region A 2 is a region sandwiched between the interface P 1 and an imaginary plane SAI that is located at a distance of 0.3 μm from the interface P 1 toward the surface side of the coating;
the titanium compound layer is composed of a plurality of titanium compound particles;
the titanium compound particles are one selected from the group consisting of TiCN particles, TiCNO particles, TiAlCN particles and TiAlCNO particles:
the titanium compound layer comprises a region B 1 and a region B 2 ;
the region B 1 is a region sandwiched between an imaginary plane SB 2 , which is located at a distance of 0 . 5 um from the interface P 1 toward the base material side, and an imaginary plane SB 3 , which is located at a distance of 1.0 μm from the interface P 1 toward the base material side;
the region B 2 is a region sandwiched between the interface Pl and an imaginary plane SB 1 that is located at a distance of 0.3 um from the interface P 1 toward the base material side;
an average particle diameter al of the α-Al 2 O 3 particles in the region A 1 , an average particle diameter a2 of the α-Al 2 O 3 particles in the region A 2 , an average particle diameter b1 of the titanium compound particles in the region B 1 , and an average particle diameter b2 of the titanium compound particles in the region B 2 satisfy relationships represented by respective expressions 1 to 3:
0.8
≤
a
2
/
b
2
≤
1.27
Expression
1
1.5
≤
a
1
/
a
2
≤
10
Expression
2
1.45
≤
b
1
/
b
2
≤
5
;
and
Expression
3
the average particle diameter b1 is 0.10 μm or more and 0.50 μm or less.
2 . The cutting tool according to claim 1 , wherein:
a ratio R 1 /R 2 between a ratio RI of the number of carbon atoms relative to the total number of carbon, nitrogen and oxygen atoms in the region B 1 and a ratio R 2 of the number of carbon atoms relative to the total number of carbon, nitrogen and oxygen atoms in the region B 2 is 0.9 or more and 1.1 or less;
a ratio R 3 of the total number of carbon and nitrogen atoms relative to the total number of carbon, nitrogen and oxygen atoms in the region B 1 is 0.8 or more and 1.0 or less; and
a ratio R 4 of the total number of carbon and nitrogen atoms relative to the total number of carbon, nitrogen and oxygen atoms in the region B 2 is 0.8 or more and 1.0 or less.
3 . The cutting tool according to claim 1 , wherein:
a ratio a1/b1 of the average particle diameter a1 to the average particle diameter b1 is 1.50 or more and 5 or less; and
the average particle diameter a1 is 0.40 μm or more and 1.00 μm or less.
4 . The cutting tool according to claim 1 , wherein:
an average thickness of the titanium compound layer is 1.0 μm or more and 15 μm or less; and
an average thickness of the α-Al 2 O 3 layer is 1.0 μm or more and 15 μm or less.
5 . The cutting tool according to claim 1 , wherein the α-Al 2 O 3 layer has a TC (0 0 12) of 3 or more in an orientation index TC (hkl).
6 . The cutting tool according to claim 1 , wherein the coating comprises a TiN layer arranged between the base material and the titanium compound layer.
7 . The cutting tool according to claim 1 , wherein the ratio a2/b2 of the average particle diameter a 2 to the average particle diameter b2 is 1.00 or more and 1.10 or less.
8 . The cutting tool according to claim 1 , wherein the ratio a1/a2 of the average particle diameter al to the average particle diameter a2 is 2.00 or more and 10 or less.
9 . The cutting tool according to claim 1 , wherein the ratio b1/b2 of the average particle diameter bl to the average particle diameter b2 is 1.50 or more and 5 or less.
10 . The cutting tool according to claim 1 , wherein a ratio a1/b1 of the average particle diameter a1 to the average particle diameter b1 is 2.00 or more and 4.50 or less.
11 . The cutting tool according to claim 1 , wherein the average particle diameter b1 is 0.15 μm or more and 0.50 μm or less.
12 . The cutting tool according to claim 5 , wherein the TC (0 0 12) is 4 or more.
13 . The cutting tool according to claim 1 , wherein the average particle diameter a1 is 0.30 μm or more and 1.20 μm or less.