Surface-coated boron nitride sintered body tool
A surface-coated boron nitride sintered body tool includes a cubic boron nitride sintered body and a coating film formed thereon. The coating film includes an A layer and a C layer. The A layer is formed of Ti 1-xa Ma xa C 1-ya N ya (where Ma is one or more of Cr, Nb and W; 0≤xa≤0.7; 0≤ya≤1). The C layer is formed of Al 1-(xc+yc) Cr xc Mc yc N (where Mc is one or more of Ti, V and Si; 0.2≤xc≤0.8; 0≤yc≤0.6; 0.2≤xc+yc≤0.8). The A layer is formed on an outermost surface of the coating film or between the outermost surface of the coating film and the C layer. A distance between the outermost surface of the coating film and an upper surface of the C layer is 0.1 μm or more and 1.0 μm or less.
1. A surface-coated boron nitride sintered body tool comprising: a cubic boron nitride sintered body; and a coating film formed thereon,
the coating film including an A layer and a C layer,
the A layer being formed of Ti 1-xa Ma xa C 1-ya N ya (where Ma is one or more of Cr, Nb and W; xa is 0≤xa≤0.7; and ya is 0≤ya≤1),
the C layer being formed of Al 1-(xc+yc) Cr xc Mc yc N (where Mc is one or more of Ti, V and Si; xc is 0.2≤xc≤0.8; yc is 0≤yc≤0.6; and xc+yc is 0.2≤xc+yc≤0.8),
the A layer being formed on an outermost surface of the coating film or between the outermost surface of the coating film and the C layer,
a distance between the outermost surface of the coating film and an upper surface of the C layer being 0.1 μm or more and 1.0 μm or less, and
a thickness of the A layer is 0.1 μm or more and 0.7 μm or less.
2. The surface-coated boron nitride sintered body tool according to claim 1 , wherein the distance between the outermost surface of the coating film and the upper surface of the C layer is 0.3 μm or more and 0.7 μm or less.
3. The surface-coated boron nitride sintered body tool according to claim 1 , wherein the C layer has a thickness of 0.1 μm or more and 1.0 μm or less.
4. The surface-coated boron nitride sintered body tool according to claim 1 , wherein the coating film includes a plurality of the A layers and a plurality of the C layers, and includes two or more laminated units each having the A layer disposed on the C layer.
5. The surface-coated boron nitride sintered body tool according to claim 1 , wherein
the coating film further includes a B layer between the A layer and the C layer, and
the B layer contains one or more compounds formed of: one or more elements selected from the group consisting of Al, Cr and Ti; and N.
6. The surface-coated boron nitride sintered body tool according to claim 5 , wherein the B layer includes a multilayer structure formed by alternately laminating one or more B1 layers each formed of TiN and one or more B2 layers each formed of AlCrN.
7. The surface-coated boron nitride sintered body tool according to claim 6 , wherein the B1 layers and the B2 layers each have a thickness of 0.5 nm or more and less than 30 nm.
8. The surface-coated boron nitride sintered body tool according to claim 5 , wherein the B layer contains a compound formed of AlTiCrN.
9. The surface-coated boron nitride sintered body tool according to claim 1 , wherein the A layer includes a region in which the ya changes in a slope-like manner or in a step-like manner in a thickness direction of the A layer.
10. The surface-coated boron nitride sintered body tool according to claim 1 , wherein the C layer is in contact with the cubic boron nitride sintered body.
11. The surface-coated boron nitride sintered body tool according to claim 1 , wherein the coating film has a thickness of 0.5 μm or more and 10 μm or less.