# US 12,594,606 B2 · Coated cutting tool and method for making coating layer

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- Number: US 12,594,606 B2
- Document ID: US12594606B2
- Status: Granted
- Kind: B2
- Application number: 17/968,749
- Filed: 2022-10-18
- Published: 2023-09-14
- Granted: 2026-04-07
- Earliest claimed: 2022-03-08
- Assignees: Yg-1 Co., Ltd.
- Applicants: YG-1 Co., Ltd
- Inventors: Dong Seob Kim; Hye Min Ahn; Geun Woo Park
- Web page: https://patentgrep.com/patent/US12594606B2

## CPC

- B23B 27/148: {Composition of the cutting inserts}
- 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 28/042: {including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides}
- C23C 28/044: {coatings specially adapted for cutting tools or wear applications}
- 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

Disclosed are a coated cutting tool in which a coating layer is formed and a method for making the coating layer. The coating layer of the cutting tool of the present disclosure is formed on the whole or part of a substrate, and includes an MT-TiCN layer and an α-Al2O3 layer which are formed of columnar grains. The MT-TiCN layer has texture coefficients of TC(311)>1.5 and TC(422)>1.5 and is formed of TiCN deposited by a chemical vapor deposition method within the range of 800° C. to 950° C., and the α-Al2O3 layer is formed of columnar grains and has TC(006)>4. The coating layer of the present disclosure may form a coating layer (coating) having excellent wear resistance and chipping resistance by depositing, an α-Al2O3 layer having a strong orientation in a <001> crystallographic direction with excellent adhesion, without using an HT-TiCN layer as in the related art.

## Claims

### Claim 1

A cutting tool comprising a substrate and a coating layer formed on whole or part of the surface of the substrate, wherein the coating layer comprises an MT-TiCN layer formed by an MTCVD technique, a TiCNO bonding layer that is a bonding layer directly deposited on the surface of the MT-TiCN layer, and an α-Al2O3 layer, which are sequentially formed from the substrate side,
wherein an HT-TiCN layer does not exist between the MT-TiCN layer and the α-Al2O3 layer, and
the MT-TiCN layer has a columnar structure and has texture coefficients of TC(311)>1.5 and TC(422)>1.5, and the α-Al2O3 layer has a texture coefficient of TC(006)>4 and is formed of columnar grains,
wherein the TC(311), TC(422), and TC(006) are defined according to Harris formula:
TC
⁡
(
hkl
)
=
I
⁡
(
hkl
)
I
0
(
hkl
)
[
1
n
⁢
∑
n
=
1
n
⁢
I
⁡
(
hkl
)
I
0
(
hkl
)
]
-
1
wherein I(hkl) above is the reflection or diffraction intensity of the measured (hkl) plane,
I0(hkl) above is the standard intensity according to the powder diffraction file (PDF) of International Centre for Diffraction Data (ICDD), and the standard intensity according to the PDF Card No. 42-1489 of ICDD is used to calculate the texture coefficient of the MT-TiCN layer, and the standard intensity according to the PDF Card No. 42-1212 of ICDD is used to calculate the texture coefficient of the α-Al2O3 layer,
n is the number of reflecting planes used in the calculation of the texture coefficients, and
the (hkI) reflecting planes used in the calculation of the texture coefficient of the MT-TiCN layer are (111), (200), (220), (311), and (422) and the (hkI) reflecting planes used in the calculation of the texture coefficient of the α-Al2O3 layer are (012), (104), (110), (006), (113), and (116).

### Claim 2 (depends on 1)

The cutting tool of claim 1, wherein the MT-TiCN layer comprises a lower layer and an upper layer, and
a deposition temperature of the upper layer is 1.11-1.15 times higher than that of the lower layer.

### Claim 3 (depends on 2)

The cutting tool of claim 2, wherein the lower layer is deposited by a chemical vapor deposition (CVD) method using H2, TiCl4, and CH3CN as source at 850° C. at an initial stage, and using H2, N2, TiCl4, and CH3CN as source at 850° C. at a middle stage, and the upper layer is deposited by the CVD method using H2, N2, TiCl4, CH3CN, and HCl as source at 950° C.

### Claim 4 (depends on 2)

The cutting tool of claim 2, wherein the thickness of the TICNO bonding layer is 0.2-1.3 μm.

### Claim 5 (depends on 3)

The cutting tool of claim 3, wherein the thickness of the α-Al2O3 layer is 1.5-10 μm, and the thickness of the MT-TiCN layer is 2-12 μm.

### Claim 6 (depends on 1)

The cutting tool of claim 1, wherein the surface of the coating layer is subjected to a brushing process using a paste containing diamond powder.

### Claim 7 (depends on 2)

The cutting tool of claim 2, wherein the coating layer further comprises a TiN layer formed on the upper surface of the α-Al2O3 layer using a mixed gas of H2, N2, and TiCl4 as source.

### Claim 8 (depends on 7)

The cutting tool of claim 7, wherein the surface of the coating layer is subjected to a brushing process using a paste containing diamond powder.

### Claim 9

A method for making a coating layer on the whole or part of a substrate of a cutting tool, the method comprising:
depositing a TiN layer on the upper surface of the substrate;
depositing an MT-TiCN layer which has texture coefficients of TC(311)>1.5 and TC(422)>1.5 and is formed of columnar grains of TiCN deposited on the TiN layer by a chemical vapor deposition method within the range of 800° C. to 950° C.;
depositing an TiCNO bonding layer on the upper surface of the MT-TiCN layer, and then oxidizing the TICNO bonding layer for a predetermined time using H2, N2, CO, and CO2; and
depositing, on the oxidized TiCNO bonding layer, an α-Al2O3 layer which has a texture coefficient of TC(006)>4 and is formed of columnar grains,
wherein an HT-TiCN layer does not exist between the MT-TiCN layer and the α-Al2O3 layer, and
wherein the TC(311), TC(422), and TC(006) are defined according to Harris formula:
TC
⁡
(
hkl
)
=
I
⁡
(
hkl
)
I
0
(
hkl
)
[
1
n
⁢
∑
n
=
1
n
⁢
I
⁡
(
hkl
)
I
0
(
hkl
)
]
-
1
,
wherein I(hkl) above is the reflection or diffraction intensity of the measured (hkl) plane,
I0(hkl) above is the standard intensity according to PDF of ICDD, and the standard intensity according to the PDF Card No. 42-1489 of ICDD is used to calculate the texture coefficient of the MT-TiCN layer, and the standard intensity according to the PDF Card No. 42-1212 of ICDD is used to calculate the texture coefficient of the α-Al2O3 layer,
n is the number of reflecting planes used in the calculation of the texture coefficients, and
the (hkI) reflecting planes used in the calculation of the texture coefficient of the MT-TiCN layer are (111), (200), (220), (311), and (422) and the (hkI) reflecting planes used in the calculation of the texture coefficient of the α-Al2O3 layer are (012), (104), (110), (006), (113), and (116).

### Claim 10 (depends on 9)

The method of claim 9, wherein the MT-TiCN layer comprises a lower layer and an upper layer, and
a deposition temperature of the upper layer is 1.11-1.15 times higher than that of the lower layer.

### Claim 11 (depends on 10)

The method of claim 10, wherein the lower layer is deposited by a chemical vapor deposition (CVD) method using H2, TiCl4, and CH3CN as source at 850° C. at an initial stage, and using H2, N2, TiCl4, and CH3CN as source at 850° C. at a middle stage, and the upper layer is deposited by the CVD method using H2, N2, TiCl4, CH3CN, and HCl as source at 950° C.

### Claim 12 (depends on 10)

The method of claim 10, wherein the thickness of the TiCNO bonding layer is 0.2-1.3 μm.

### Claim 13 (depends on 12)

The method of claim 12, wherein the thickness of the α-Al2O3 layer is 1.5-10 μm, and the thickness of the MT-TiCN layer is 2-12 μm.

### Claim 14 (depends on 10)

The method of claim 10, further comprising subjecting the surface of the coating layer to a brushing process using a paste containing diamond powder.

### Claim 15 (depends on 10)

The method of claim 10, further comprising making a TiN layer on the upper surface of the α-Al2O3 layer using a mixed gas of H2, N2, and TiCl4 as source.

### Claim 16 (depends on 15)

The method of claim 15, further comprising subjecting the surface of the coating layer to a brushing process using a paste containing diamond powder.