# US 2022/0033975 A1 · Ta-c based coatings with improved hardness

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- Number: US 2022/0033975 A1
- Document ID: US20220033975A1
- Status: Published application
- Kind: A1
- Application number: 17/291,378
- Filed: 2019-11-07
- Published: 2022-02-03
- Earliest claimed: 2018-11-08
- Assignees: Nanofilm Technologies International Limited
- Applicants: Nanofilm Technologies International Limited
- Inventors: Xu SHI; Zhi TANG
- Web page: https://patentgrep.com/patent/US20220033975A1

## CPC

- 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 14/025: {Metallic sublayers}
- C23C 14/0605: {Carbon}
- C23C 14/0635: {Carbides}
- C23C 14/325: {Electric arc evaporation}
- C23C 14/3407: {Cathode assembly for sputtering apparatus, e.g. Target}
- C23C 28/048: {with layers graded in composition or physical properties}
- C23C 28/36: {including layers graded in composition or physical properties}
- 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: 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 substrate is coated with a multi-layer coating, comprising in order: (i) a first functional layer comprising ta-C, (ii) a second functional layer comprising ta-C, (iii) (a) a third functional layer comprising ta-C and a first intermediate layer comprising a carbide of a first element, or (b) a first intermediate layer comprising a carbide of a first element, and a second intermediate layer comprising the first element, wherein the ta-C has a hydrogen content less than 10% and an sp2 content less than 30%; wherein (i) the Young's modulus or (ii) the hardness or (iii) both the Young's modulus and the hardness independently stay the same or increase from layer to layer in (iii) (a) from the first intermediate layer to the first functional layer, or in (iii) (b) from the second intermediate layer to the first functional layer.

## Claims

### Claim at position 1

1-49. (canceled)

### Claim 50

A substrate coated with a multi-layer coating, comprising in order from the outside towards the substrate:
a first functional ta-C-containing layer of hardness 2000 HV or greater,
a second functional ta-C-containing layer of hardness 1200 HV or greater,
a first intermediate layer comprising tungsten carbide,
a second intermediate layer comprising chromium tungstide, and
a further intermediate layer comprising chromium and adjacent the substrate,
wherein the ta-C has a hydrogen content less than 10% and an sp2 content less than 30%;
wherein the first functional layer has a hardness at least 200 HV greater than the second functional layer; and
wherein (1) the Young's modulus or (2) the hardness or (3) both the Young's modulus and the hardness independently stay the same or increase from layer to layer from the second intermediate layer to the first functional layer.

### Claim 51 (depends on 50)

A coated substrate according to claim 50, wherein the coating comprises one or more further functional layers comprising ta-C between the second functional layer and the first intermediate layer.

### Claim 52 (depends on 50)

A coated substrate according to claim 50, wherein the ta-C has a hydrogen content of 5% or less and an sp2 content of 20% or less.

### Claim 53 (depends on 50)

A coated substrate according to claim 50, wherein the substrate is steel or a variety of steel (e.g. steel, stainless steel, HSS, tool steel and alloy steel).

### Claim 54 (depends on 50)

A coated substrate according to claim 50, wherein the Young's modulus increases over a set of three adjacent layers in the coating.

### Claim 55 (depends on 54)

A coated substrate according to claim 54, wherein the average increase in the Young's modulus is 10 GPa per layer, or more.

### Claim 56 (depends on 50)

A coated substrate according to claim 50, wherein the coating has a hardness of at least 2000 HV.

### Claim 57 (depends on 50)

A coated substrate according to claim 50, wherein the coating has a hardness of at least 4000 HV.

### Claim 58 (depends on 50)

A coated substrate according to claim 50, wherein the hardness increases over any set of three adjacent layers in the coating.

### Claim 59 (depends on 57)

A coated substrate according to claim 57, wherein the average increase in hardness is at least 300 HV per layer.

### Claim 60 (depends on 59)

A coated substrate according to claim 59, wherein the average increase in hardness is at least 400 HV per layer.

### Claim 61 (depends on 50)

A coated substrate according to claim 50, wherein the hardness of the functional layer adjacent the first intermediate layer is 1600 HV or more.

### Claim 62 (depends on 50)

A coated substrate according to claim 50, wherein the coating has a total thickness of 5 microns or less.

### Claim 63 (depends on 50)

A coated substrate according to claim 50, wherein the coating has a total thickness of 2 microns or less.

### Claim 64 (depends on 50)

A coated substrate according to claim 50, wherein each layer of the coating has a thickness of 1 micron or less.

### Claim 65 (depends on 50)

A coated substrate according to claim 50, wherein the substrate is selected from tools, cutting tools, tooling, industrial machines and components therefor.

### Claim 66 (depends on 50)

A coated substrate according to claim 50, wherein the substrate is an engine component (e.g. a piston ring, a piston pin, a cam shaft, a tappet, a lift valve and an injection nozzle).

### Claim 67 (depends on 50)

A method of making a coated substrate according to claim 50, comprising providing the substrate, and coating onto the substrate, in order:
a further intermediate layer comprising chromium,
a second intermediate layer comprising chromium tungstide,
a first intermediate layer comprising tungsten carbide,
a second functional ta-C containing layer of hardness 1200 HV or greater,
a first functional ta-C containing layer of hardness 2000 HV or greater,
wherein the ta-C has a hydrogen content less than 10% and an sp2 content less than 30%;
wherein the first functional layer has a hardness at least 200 HV greater than the second functional layer;
wherein (1) the Young's modulus or (2) the hardness or (3) both the Young's modulus and the hardness independently stay the same or increase from layer to layer from the second intermediate layer to the first functional layer.

### Claim 68 (depends on 67)

A method according to claim 67, wherein the functional layers are deposited by PVD, e.g. sputtering or CVA.

### Claim 69 (depends on 28)

A method according to claim 28, wherein the functional layers are deposited by FCVA.