# US 11,299,807 B2 · Surface-coated cutting tool in which hard coating layer exhibits exceptional adhesion resistance and anomalous damage resistance

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- Number: US 11,299,807 B2
- Document ID: US11299807B2
- Status: Granted
- Kind: B2
- Application number: 16/641,262
- Filed: 2018-09-26
- Published: 2020-11-12
- Granted: 2022-04-12
- Earliest claimed: 2017-09-29
- Assignees: Mitsubishi Materials Corporation
- Applicants: Mitsubishi Materials Corporation
- Inventors: Akihiro Murakami; Masaki Okude; Shin Nishida
- Web page: https://patentgrep.com/patent/US11299807B2

## CPC

- C23C 28/044: {coatings specially adapted for cutting tools or wear applications}
- B23B 27/14: Cutting tools of which the bits or tips {or cutting inserts} are of special material
- B23C 5/16: characterised by physical features other than shape
- C22C 29/005: {comprising a particular metallic binder}
- C22C 29/08: based on tungsten carbide
- C23C 16/0272: {Deposition of sub-layers, e.g. to promote the adhesion of the main coating}
- C23C 16/32: Carbides
- C23C 16/34: Nitrides {(C23C16/303 takes precedence)}
- C23C 16/403: {of aluminium, magnesium or beryllium}
- C23C 16/45523: {Pulsed gas flow or change of composition over time}
- C23C 28/04: only coatings of inorganic non-metallic material
- C23C 28/042: {including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides}
- C23C 30/005: {on hard metal substrates}
- 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)
- B23B: TURNING; BORING (arrangements for copying or controlling B23Q)
- B23C: MILLING (broaching B23D; broach-milling in making gears B23F; arrangement for copying or controlling B23Q)
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

A surface-coated cutting tool in which a hard coating layer exhibits exceptional adhesion resistance and anomalous damage resistance is provided. This surface-coated cutting tool includes a tool body composed of a WC based cemented carbide or a TiCN based cermet; and at least one hard coating layer provided on a surface of the tool body, and; 1) the hard coating layer includes at least one complex nitride layer, 2) the complex nitride layer contains 0.001 to 0.030 atom % of chlorine, 3) in the complex nitride layer, an area ratio of longitudinal crystal grains having an aspect ratio equal to or greater than 2 occupying a longitudinal cross section is 50% or more, and 4) a layer thickness of the complex nitride layer is 0.2 μm to 20 μm.

## Claims

### Claim 1

A surface-coated cutting tool comprising:
a tool body composed of a cemented carbide comprising WC or a cermet comprising TiCN; and
at least one hard coating layer provided on a surface of the tool body, wherein
1) the hard coating layer includes at least one complex nitride layer in which, in a case where the complex nitride layer is expressed by a compositional formula (Ti(1-x)ZrxyHfx(1-y))N, x and y satisfy 0.05≤x≤0.95 and 0<y≤1.0, respectively, where x is a content ratio of a total amount of Zr and Hf to a total amount of Ti, Zr, and Hf, and y is a content ratio of Zr to a total amount of Zr and Hf (here, all of x and y are atomic ratios);
2) the complex nitride layer contains 0.001 to 0.030 atom % of chlorine;
3) in the complex nitride layer, an area ratio of longitudinal crystal grains having an aspect ratio equal to or greater than 2 occupying a longitudinal cross section is 50% or more; and
4) a layer thickness of the complex nitride layer is 0.2 μm or more and 20 μm or less.

### Claim 2 (depends on 1)

The surface-coated cutting tool according to claim 1,
wherein the complex nitride layer has:
1) a nanoindentation hardness of 2,600 kgf/mm2 or more in a case where an indentation load is 200 mgf; and
2) a layer thickness of 1 μm or more and 20 μm or less.

### Claim 3 (depends on 1)

The surface-coated cutting tool according to claim 1, wherein y satisfies 0<y<1.0.

### Claim 4 (depends on 1)

The surface-coated cutting tool according to claim 1, wherein x satisfies 0.08≤x≤0.92, y satisfies 0.1≤y≤1.0, the complex nitride layer contains 0.003 to 0.026 atom % of chlorine, and the complex nitride layer contains no carbon.

### Claim 5 (depends on 1)

The surface-coated cutting tool according to claim 1, wherein the complex nitride layer is formed by a method comprising:
a first primary nucleus formation step of forming primary nucleus for forming a TiZrN film or a TiZrHfN film, and
a second crystal growth step of growing the primary nuclei to form the TiZrN film or the TiZrHfN film,
wherein the first primary nucleus formation step comprises:
a seed film formation step of forming a ZrN film or a ZrHfN film which are seed films, and
an etching step of etching a surface of the ZrN film or the ZrHfN film formed in the seed film formation step to substitute a part of Zr with Ti, and obtaining the primary nucleus of TiZrN or TiZrHfN.