# US 11,992,882 B2 · Cutting tool

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- Number: US 11,992,882 B2
- Document ID: US11992882B2
- Status: Granted
- Kind: B2
- Application number: 17/793,036
- Filed: 2020-04-24
- Published: 2023-05-18
- Granted: 2024-05-28
- Earliest claimed: 2020-04-24
- Assignees: Sumitomo Electric Hardmetal Corp.; Sumitomo Electric Industries, Ltd.
- Applicants: Sumitomo Electric Hardmetal Corp.; Sumitomo Electric Industries, Ltd.
- Inventors: Haruyo Fukui; Daiji Tabayashi; Yoshihiro Saito; Kazuya Tokuda; Yoshiharu Utsumi; Hajime Takamatsu
- Web page: https://patentgrep.com/patent/US11992882B2

## CPC

- B23B 27/14: Cutting tools of which the bits or tips {or cutting inserts} are of special material
- C04B 41/009: {characterised by the material treated}
- C04B 41/5001: {with carbon or carbonisable materials}
- C04B 41/52: Multiple coating or impregnating {multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation}
- C22C 29/08: based on tungsten carbide
- C23C 14/0021: {Reactive sputtering or evaporation}
- C23C 14/022: {by means of bombardment with energetic particles or radiation}
- C23C 14/024: {Deposition of sublayers, e.g. to promote adhesion of the coating (C23C14/027 takes precedence)}
- C23C 14/0605: {Carbon}
- C23C 14/0635: {Carbides}
- C23C 14/325: {Electric arc evaporation}
- C23C 28/04: only coatings of inorganic non-metallic material
- C23C 28/044: {coatings specially adapted for cutting tools or wear applications}
- C23C 28/046: {with at least one amorphous inorganic material layer, e.g. DLC, a-C:H, a-C:Me, the layer being doped or not}
- C23C 30/005: {on hard metal substrates}
- B23B 2226/125: cubic [CBN]
- B23B 2228/105: with specified thickness
- C04B 2111/0025: {Compositions or ingredients of the compositions characterised by the crystal structure}
- Y10T 428/30: Self-sustaining carbon mass or layer with impregnant or other layer
- B23B: TURNING; BORING (arrangements for copying or controlling B23Q)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- 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)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Provided is a cutting tool that can have a long tool life even when used to cut soft metals in particular. The cutting tool comprises a base body and a hard carbon film arranged on the base body, the hard carbon film includes an amorphous phase and a graphite phase, the density of the hard carbon film is no less than 2.5 g/cm3 and no more than 3.5 g/cm3, the degree of crystallinity of the hard carbon film is no more than 6.5%, and the average coordination number of the amorphous phase is no less than 2.5 and no more than 4.

## Claims

### Claim 1

A cutting tool comprising a base body and a hard carbon film arranged on the base body, wherein
the hard carbon film includes an amorphous phase and a graphite phase,
a density of the hard carbon film is no less than 2.5 g/cm3 and no more than 3.5 g/cm3,
a degree of crystallinity of the hard carbon film is no more than 6.5%, and
an average coordination number of the amorphous phase is no less than 2.5 and no more than 4.

### Claim 2 (depends on 1)

The cutting tool according to claim 1, wherein the hard carbon film has a thickness of no less than 0.1 μm and no more than 3 μm at a portion involved in cutting.

### Claim 3 (depends on 1)

The cutting tool according to claim 1, wherein the hard carbon film has a hydrogen content of no more than 5 atom %.

### Claim 4 (depends on 1)

The cutting tool according to claim 1, wherein the base body and the hard carbon film are in contact with each other.

### Claim 5 (depends on 1)

The cutting tool according to claim 1, comprising an interface layer disposed between the base body and the hard carbon film,
wherein the interface layer contains:
at least one selected from the group consisting of a material made of a single element selected from a first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, Group 13 elements, and Group 14 elements excluding carbon in the Periodic Table, an alloy or first compound containing at least one element selected from the first group, and a solid solution derived from the first compound; or
one or both of a second compound composed of at least one element selected from the first group and carbon, and a solid solution derived from the second compound, and
the interface layer has a thickness of no less than 0.5 nm and less than 10 nm.

### Claim 6 (depends on 1)

The cutting tool according to claim 1, wherein the base body is composed of WC-based cemented carbide or cermet.

### Claim 7 (depends on 1)

The cutting tool according to claim 1, wherein the base body is composed of cubic boron nitride.

### Claim 8 (depends on 1)

The cutting tool according to claim 1, wherein the density of the hard carbon film is no less than 3.0 g/cm3 and no more than 3.5 g/cm3.

### Claim 9 (depends on 1)

The cutting tool according to claim 1, wherein the density of the hard carbon film is no less than 3.2 g/cm3 and no more than 3.4 g/cm3.

### Claim 10 (depends on 1)

The cutting tool according to claim 1, wherein the degree of crystallinity of the hard carbon film is no less than 2% and no more than 6.5%.

### Claim 11 (depends on 1)

The cutting tool according to claim 1, wherein the degree of crystallinity of the hard carbon film is no less than 3% and no more than 5%.

### Claim 12 (depends on 1)

The cutting tool according to claim 1, wherein the average coordination number of the amorphous phase is no less than 3.5 and no more than 4.

### Claim 13 (depends on 1)

The cutting tool according to claim 1, wherein the hard carbon film has a thickness of no less than 0.5 μm and no more than 3 μm at a portion involved in cutting.

### Claim 14 (depends on 1)

The cutting tool according to claim 1, wherein the hard carbon film consists of the amorphous phase and the graphite phase.

### Claim 15 (depends on 1)

The cutting tool according to claim 1, wherein the hard carbon film has a hydrogen content of no less than 0 atom % and no more than 5 atom %.