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

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.

Claims15

Dependent claims

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.

44 more elements

Dependencies are inferred from the claim text.

Control and characterization of texture in CVD α-Al2O3 coatings

Life of this patent

Control and characterization of texture in CVD α-Al2O3 coatings

Life of this patent

Abstract

Claims15