# US 10,865,476 B2 · Control and characterization of texture in CVD α-Al2O3 coatings

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,865,476 B2
- Document ID: US10865476B2
- Status: Granted
- Kind: B2
- Application number: 15/926,504
- Filed: 2018-03-20
- Published: 2018-09-27
- Granted: 2020-12-15
- Earliest claimed: 2017-03-23
- Assignees: Kennametal Inc.
- Applicants: Kennametal Inc.
- Inventors: Chen Chen; Zhenyu Liu; Peter Rudolf Leicht; Rodrigo Alejandro Cooper
- Web page: https://patentgrep.com/patent/US10865476B2

## CPC

- C23C 16/403: {of aluminium, magnesium or beryllium}
- C23C 16/0272: {Deposition of sub-layers, e.g. to promote the adhesion of the main coating}
- C23C 16/52: Controlling or regulating the coating process {(C23C16/45557, C23C16/279 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

CVD Alumina coating has been one of the most important materials for wear resistant application for many years. Recently, texture control in α-Al2O3 has attracted increasing attention due to the possibility to further improve the anisotropic properties such as thermal conductivity and mechanical properties. The influence of process parameters on textures is complex. In the present application, the influence of nucleation surface condition and H2S on the texture in CVD α-Al2O3 coatings has been investigated. It has been shown that without the addition of H2S, the crystal orientation in the Al2O3 coatings is primarily dominated by the nucleation surface condition, whereas the effect of reactant composition on texture is minimal. On the other hand, in the presence of H2S during growth, reactant composition also plays an important role in affecting the crystal orientation. This effect is likely due to the strong interaction between the Al2O3 surface and the H2S.

## Claims

### Claim 1

A coated article comprising:
a substrate; and
a coating adhered to the substrate, the coating comprising a layer of α-Al2O3 deposited by chemical vapor deposition (CVD), the α-Al2O3 layer comprising a gradient of two or more texture coefficients (TC) along thickness of the α-Al2O3 layer, wherein the texture coefficients of the gradient are selected from the (012), (104), (110), (006), (113), (202), (024) and (116) growth directions and defined as:
TC
⁡
(
hkl
)
=
I
⁡
(
hkl
)
I
o
⁡
(
hkl
)
⁢
{
1
n
⁢
Σ
⁢
I
⁡
(
hkl
)
I
o
⁡
(
hkl
)
}
-
1
where
I(hkl)=measured intensity of the (hkl) reflection
Io(hkl)=standard intensity of the (hkl) reflection according to International Center for Diffraction Data (ICDD) card 43-1484
n=number of reflections used in the TC calculation
(hkl) reflections used in the TC calculation are (012), (104), (110), (006), (113), (202), (024) and (116),
wherein the gradient comprises a nucleation TC in the (110) growth direction and a bulk TC.

### Claim 2 (depends on 1)

The coated article of claim 1, wherein the nucleation TC has a value greater than 5 in the (110) growth direction.

### Claim 3 (depends on 2)

The coated article of claim 2, wherein the bulk TC has a value greater than 3 in the (012) growth direction.

### Claim 4 (depends on 2)

The coated article of claim 2, wherein the bulk TC has a value greater than 4 in the (006) growth direction.

### Claim 5 (depends on 1)

The coated article of claim 1, wherein the nucleation TC extends into the α-Al2O3 layer a distance of up to 1 μm from a surface on which the α-Al2O3 layer is deposited.

### Claim 6 (depends on 1)

The coated article of claim 1, wherein the nucleation TC extends into the α-Al2O3 layer a distance of 50-500 nm from a surface on which the α-Al2O3 layer is deposited.

### Claim 7 (depends on 1)

The coated article of claim 1, wherein growth directions of the nucleation TC and bulk TC are offset by at least 45 degrees.

### Claim 8 (depends on 1)

The coated article of claim 1, wherein growth directions of the nucleation TC and bulk TC are offset by 90 degrees.

### Claim 9

A coated article comprising:
a substrate; and
a coating adhered to the substrate, the coating comprising a layer of α-Al2O3 deposited by chemical vapor deposition (CVD), the α-Al2O3 layer comprising a gradient of two or more texture coefficients (TC) along thickness of the α-Al2O3 layer, wherein the texture coefficients of the gradient are selected from the (012), (104), (110), (006), (113), (202), (024) and (116) growth directions and defined as:
TC
⁡
(
hkl
)
=
I
⁡
(
hkl
)
I
o
⁡
(
hkl
)
⁢
{
1
n
⁢
Σ
⁢
I
⁡
(
hkl
)
I
o
⁡
(
hkl
)
}
-
1
where
I(hkl)=measured intensity of the (hkl) reflection
Io(hkl)=standard intensity of the (hkl) reflection according to International Center for Diffraction Data (ICDD) card 43-1484
n=number of reflections used in the TC calculation
(hkl) reflections used in the TC calculation are (012), (104), (110), (006), (113), (202), (024) and (116),
wherein the layer of α-Al2O3 has a grain size gradient between a nucleation zone and a bulk zone, the bulk zone having larger grains with higher aspect ratio relative to grains of the nucleation zone.

### Claim 10 (depends on 9)

The coated article of claim 9, wherein the gradient comprises a nucleation TC and a bulk TC.

### Claim 11 (depends on 10)

The coated article of claim 10, wherein the nucleation TC is in the (110) growth direction.

### Claim 12 (depends on 11)

The coated article of claim 11, wherein the bulk TC is in the (006) growth direction.

### Claim 13 (depends on 11)

The coated article of claim 11, wherein the bulk TC is in the (012) growth direction.

### Claim 14 (depends on 10)

The coated article of claim 10, wherein growth directions of the nucleation TC and bulk TC are offset by at least 45 degrees.

### Claim 15 (depends on 10)

The coated article of claim 10, wherein growth directions of the nucleation TC and bulk TC are offset by 90 degrees.