# US 12,599,971 B2 · Coated cutting tool

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- Number: US 12,599,971 B2
- Document ID: US12599971B2
- Status: Granted
- Kind: B2
- Application number: 18/563,474
- Filed: 2022-05-25
- Published: 2024-07-18
- Granted: 2026-04-14
- Earliest claimed: 2021-05-27
- Assignees: AB Sandvik Coromant
- Applicants: AB Sandvik Coromant
- Inventors: Linus Von Fieandt; Raluca Morjan Brenning; Jan Engqvist
- Web page: https://patentgrep.com/patent/US12599971B2

## CPC

- B23B 27/148: {Composition of the cutting inserts}
- C23C 28/042: {including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides}
- C23C 16/0272: {Deposition of sub-layers, e.g. to promote the adhesion of the main coating}
- C23C 16/308: {Oxynitrides}
- C23C 16/34: Nitrides {(C23C16/303 takes precedence)}
- C23C 16/36: Carbonitrides
- C23C 16/403: {of aluminium, magnesium or beryllium}
- C23C 16/56: After-treatment
- C23C 28/044: {coatings specially adapted for cutting tools or wear applications}
- C23C 30/005: {on hard metal substrates}
- B23B 2228/105: with specified thickness
- B23B: TURNING; BORING (arrangements for copying or controlling B23Q)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## Abstract

A cutting tool includes a substrate at least partially coated with a coating. The substrate is a cemented carbide, cermet or ceramic. The coating includes a layer of Ti(C,N), a layer of Al2O3 and there between a bonding layer. The Ti(C,N) layer is composed of columnar grains, wherein an average grain size D422 of the Ti(C,N) layer is 25-50 nm, and wherein the Ti(C,N) layer includes a portion B1 that is adjacent to the bonding layer. An average grain size of the Ti(C,N) grains in portion B1 is larger than the average grain size D422 in the whole Ti(C,N) layer. In the portion B1 of Ti(C,N) layer the Ti(C,N) grains has an average grain size of 140-300 nm.

## Claims

### Claim 1

A cutting tool comprising a substrate at least partially coated with a coating, said coating including a layer of Ti(C,N), a layer of Al2O3 and there between a bonding layer, wherein said Ti(C,N) layer has a thickness of 3-25 μm and is composed of columnar grains, wherein an average grain size D422 of the Ti(C,N) layer is 25-50 nm, as measured with X-ray diffraction with CuKα radiation, the average grain size D422 is calculated from the full width at half maximum (FWHM) of the (422) peak according to Scherrer's equation:
D
422
=
K
⁢
λ
B
422
⁢
cos
⁢
θ
wherein D422 is the average grain size of the Ti(C,N), K is the shape factor here set at 0.9, λ is the wave length for the CuKα radiation here set at 1.5405 Å, B422 is the FWHM value for the (422) reflection and θ is the Bragg angle, wherein the Ti(C,N) layer includes a portion B1 that is adjacent to the bonding layer, and wherein an average grain size of the Ti(C,N) grains in portion B1 is larger than the average grain size D422 over a whole thickness of the Ti(C,N) layer, in the portion B1 of Ti(C,N) layer the Ti(C,N) grains has an average grain size of 140-300 nm as measured in the portion B1 of the Ti(C,N) layer, within 0.5 μm from the bonding layer, as measured by counting a number of grains along a line in a SEM micrograph at a 15.000× magnification, wherein said line is parallel with the substrate surface.

### Claim 2 (depends on 1)

The cutting tool according claim 1, wherein a thickness of the portion B1 of the Ti(C,N) layer is 0.5-1.5 μm.

### Claim 3 (depends on 1)

The cutting tool according to claim 1, wherein the bonding layer includes at least one kind compound selected from the group of titanium carboxide, titanium oxynitride and titanium carboxynitride.

### Claim 4 (depends on 1)

The cutting tool according to claim 1, wherein the average grain size D422 of Ti(C,N) is 25-40 nm.

### Claim 5 (depends on 1)

The cutting tool according to claim 1, wherein the Ti(C,N) layer exhibits an X-ray diffraction pattern, as measured using CuKα radiation and θ-2θ scan, wherein the TC(hkl) is defined according to Harris formula:
TC
⁡
(
hkl
)
=
I
⁡
(
hkl
)
I
0
(
hkl
)
[
1
n
⁢
∑
n
=
1
n
⁢
I
⁡
(
hkl
)
I
0
(
hkl
)
]
-
1
where I(hkl) is the measured intensity (integrated area) of the (hkl) reflection, I0(hkl) is the standard intensity according to ICDD's PDF-card No. 42-1489, n is the number of reflections, reflections used in the calculation are (1 1 1), (2 0 0), (2 2 0), (3 1 1), (3 3 1), (4 2 0) and (4 2 2), wherein TC(422)≥3.

### Claim 6 (depends on 1)

The cutting tool according to claim 1, wherein the Al2O3 layer is a α-Al2O3 layer having an average thickness of 1 μm-15 μm.

### Claim 7 (depends on 6)

The cutting tool according to claim 6, wherein the α-Al2O3 layer exhibits a texture coefficient TC(hkl), as measured by X-ray diffraction using CuKα radiation and θ-2θ scan, defined according to Harris formula where I(hkl) is the measured intensity (integrated area) of the (hkl) reflection, I0(hkl) is the standard intensity according to ICDD's PDF-card No. 00-010-0173, n is the number of reflections used in the calculation, and where the (hkl) reflections used are (1 0 4), (1 1 0), (1 1 3), (0 2 4), (1 1 6), (2 1 4), (3 0 0) and (0 0 12) characterized in that TC(0 0 12)≥7.5.

### Claim 8 (depends on 6)

The cutting tool according to claim 6, wherein said α-Al2O3 layer exhibits a texture coefficient TC (110)≤0.2.

### Claim 9 (depends on 1)

The cutting tool according to claim 1, wherein in the portion B1 of Ti(C,N) layer the Ti(C,N) grains has an average grain size of 140 nm-175 nm.

### Claim 10 (depends on 1)

The cutting tool according to claim 1, wherein an average thickness of the Ti(C,N) layer is 4-20 μm.

### Claim 11 (depends on 1)

The cutting tool according to claim 1, wherein an average thickness of the bonding layer is 0.25-2.5 μm.

### Claim 12 (depends on 1)

The cutting tool according to claim 1, wherein an average thickness of the coating is 5.0 μm-30.0 μm.

### Claim 13 (depends on 1)

The cutting tool according to claim 1, wherein said substrate is a cemented carbide, cermet or ceramic.