# US 2014/0193637 A1 · Tool with chromium-containing functional layer

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- Number: US 2014/0193637 A1
- Document ID: US20140193637A1
- Status: Published application
- Kind: A1
- Application number: 14/238,352
- Filed: 2012-09-05
- Published: 2014-07-10
- Earliest claimed: 2011-09-07
- Assignees: Walter AG
- Inventors: Veit Schier; Wolfgang Engelhart
- Web page: https://patentgrep.com/patent/US20140193637A1

## CPC

- C23C 30/00: Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process (C23C26/00, C23C28/00 take precedence)
- C23C 14/06: characterised by the coating material ({C23C14/0021} , C23C14/04 take precedence)
- C23C 14/0641: {Nitrides (C23C14/0617 takes precedence)}
- C23C 14/08: Oxides (C23C14/10 takes precedence)
- C23C 14/081: {of aluminium, magnesium or beryllium}
- C23C 14/32: by explosion; by evaporation and subsequent ionisation of the vapours {, e.g. ion-plating}(C23C14/34 - C23C14/48 take precedence)
- C23C 14/325: {Electric arc evaporation}
- C23C 14/35: by application of a magnetic field, e.g. magnetron sputtering {(C23C14/3457 takes precedence)}
- C23C 14/354: {Introduction of auxiliary energy into the plasma}
- C23C 28/04: only coatings of inorganic non-metallic material
- C23C 28/044: {coatings specially adapted for cutting tools or wear applications}
- C23C 30/005: {on hard metal substrates}
- Y10T 428/265: 1 mil or less
- 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

Cutting tool has a substrate and a multilayer coating deposited by PVD. The coating comprises a base layer of one or more identical or different layers of a nitride or carbonitride which contains at least aluminium (Al) and a chromium-containing, oxidic functional layer. Attachment of the chromium-containing functional layer is improved by an intermediate layer of one or more oxides or oxide nitrates of the metals Al, Cr, Si, and/or Zr provided between the base layer and the functional layer. The intermediate layer has a cubic structure and the chromium-containing functional layer is selected from chromium oxide (Cr2O3), chromium oxynitride, aluminium-chromium oxide (AlCr)2O3, aluminium-chromium oxynitride or a mixed oxide or mixed oxynitride of aluminium, chromium and further metals of (AlCrMe1, Men)2 oxide or (AlCrMe1, Men)2 oxynitride, where Me . . . Men means one or more further metals, selected from Hf, Y, Zr and Ru, and wherein the functional layer has a rhombohedral structure.

## Claims

### Claim 1

Cutting tool including a substrate of hard metal carbide, cermet, steel or high-speed steel (HSS) and a multi-layer coating deposited thereon by a PVD process, wherein starting from the substrate the multi-layer coating comprises the following sequence of layers:
a) a base layer consisting of one or more identical or different layers arranged one on top of another of a nitride or carbonitride and which contains at least aluminium (Al) and optionally one or more further metals selected from Ti, Cr, Si, Y, Ru and Mo,
b) an intermediate layer arranged on top of the base layer and consisting of one or more oxides or oxynitrides of the metals Al, Cr, Si, and/or Zr, the intermediate layer exhibiting a cubic structure, and
c) a chromium-containing functional layer arranged on top of the intermediate layer and selected from chromium oxide (Cr2O3), chromium oxynitride, aluminium-chromium oxide (AlCr)2O3, aluminium-chromium oxynitride or a mixed oxide or mixed oxynitride of aluminium, chromium and further metals (AlCrMe1, . . . Men)2 oxide or (AlCrMe1, . . . Men)2 oxynitride, in which Me1, . . . Men means one or more further metals selected from Hf, Y, Zr and Ru, the functional layer exhibiting a rhombohedral structure.

### Claim 2 (depends on 1)

Cutting tool according to claim 1, wherein the intermediate layer consists of cubic aluminium oxide.

### Claim 3 (depends on 1)

Cutting tool according to claim 1, wherein the chromium-containing functional layer consists at least to the extent of 90 vol. % of rhombohedral aluminium-chromium oxide (AlCr)2O3.

### Claim 4 (depends on 1)

Cutting tool according to claim 1, wherein the proportion of chromium among metallic elements of the functional layer is at least 70 at. % Cr.

### Claim 5 (depends on 1)

Cutting tool according to claim 1, wherein the intermediate layer is deposited by magnetron sputtering, reactive magnetron sputtering, dual magnetron sputtering, high power impulse magnetron sputtering or with simultaneous application of cathode atomisation and arc evaporation.

### Claim 6 (depends on 1)

Cutting tool according to claim 1, wherein the functional layer is deposited by arc evaporation, magnetron sputtering, reactive magnetron sputtering, dual magnetron sputtering, high power impulse magnetron sputtering or with simultaneous application of cathode atomisation and arc evaporation.

### Claim 7 (depends on 1)

Cutting tool according to claim 1, wherein the base layer exhibits a coating thickness of from 50 nm to 8 μm.

### Claim 8 (depends on 1)

Cutting tool according to claim 1, wherein the intermediate layer exhibits a coating thickness of from 1 nm to 2 μm.

### Claim 9 (depends on 1)

Cutting tool according to claim 1, wherein the functional layer exhibits a coating thickness of from 100 nm to 10 μm.

### Claim 10 (depends on 1)

Cutting tool according to claim 1, wherein the functional layer exhibits pressure loadings at the surface of less than 2 GPa.

### Claim 11 (depends on 1)

Cutting tool according to claim 1, wherein the base layer consists of titanium-aluminium nitride or titanium-aluminium-silicon nitride.

### Claim 12 (depends on 1)

Cutting tool according to claim 1, wherein the intermediate layer contains 0.1 to 5 at. %, argon.

### Claim 13 (depends on 2)

Cutting tool according to claim 2, wherein the intermediate layer consists of cubic gamma aluminium oxide (γ-Al2O3).

### Claim 14 (depends on 3)

Cutting tool according to claim 3, wherein the chromium-containing functional layer consists completely of rhombohedral aluminium-chromium oxide (AlCr)2O3.

### Claim 15 (depends on 4)

Cutting tool according to claim 4, wherein the proportion of chromium among metallic elements of the functional layer is at least 85 at. % Cr.

### Claim 16 (depends on 15)

Cutting tool according to claim 15, wherein the proportion of chromium among metallic elements of the functional layer is at least 95 at. % Cr.

### Claim 17 (depends on 7)

Cutting tool according to claim 7, wherein the coating thickness of the base layer is from 500 nm to 5 μm.

### Claim 18 (depends on 8)

Cutting tool according to claim 8, wherein the coating thickness of the intermediate layer is from 5 nm to 750 nm.

### Claim 19 (depends on 9)

Cutting tool according to claim 9, wherein the coating thickness of the functional layer is from 500 nm to 5 μm.

### Claim 20 (depends on 10)

Cutting tool according to claim 10, wherein the functional layer exhibits pressure loadings at the surface of less than 1 GPa.

### Claim 21 (depends on 12)

Cutting tool according to claim 12, wherein the intermediate layer contains 0.5 to 4 at. % argon.