Coated cutting tool with h-AlN and Ti1-xAlxCyNz layers

Patent metadata

Field	Value
Publication number	US-11247276-B2
Application number	US-201716090287-A
Country	US
Kind code	B2
Filing date	Mar 31, 2017
Priority date	Mar 31, 2016
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

A coated cutting tool includes a substrate of cemented carbide, cermet, ceramics, steel or cubic boron nitride and a multi-layered wear resistant coating. The multi-layered wear resistant coating has a total thickness from 5 to 25 μm and includes refractory coating layers deposited by chemical vapour deposition (CVD) or moderate temperature chemical vapour deposition (MT-CVD). The multi-layered wear resistant coating has at least one pair of layers (a) and (b), with layer (b) being deposited immediately on top of layer (a). Layer (a) is a layer of aluminium nitride having hexagonal crystal structure (h-AlN) and a thickness from 10 nm to 750 nm. Layer (b) is a layer of titanium aluminium nitride or titanium aluminium carbonitride represented by the general formula Ti1-xAlxCyNz with 0.4≤x≤0.95, 0≤y≤0.10 and 0.85≤z≤1.15, having a thickness from 0.5 μm to 15 μm, and at least 90% of the Ti1-xAlxCyNz of layer (b) has a face-centered cubic (fcc) crystal structure.

First claim

The invention claimed is:

1. A coated cutting tool comprising:
a substrate of cemented carbide, cermet, ceramics, steel or cubic boron nitride; and
a multi-layered wear resistant coating, wherein the multi-layered wear resistant coating has a total thickness from 5 to 25 μm and includes refractory coating layers deposited by chemical vapour deposition (CVD) or moderate temperature chemical vapour deposition (MT-CVD), and the multi-layered wear resistant coating includes at least one pair of layers (a) and (b) with layer (b) being deposited immediately on top of layer (a), wherein layer (a) is a layer of aluminium nitride having hexagonal crystal structure (h-AlN) and a thickness from 10 nm to 750 nm with a chlorine content of less than 5 at.-% and layer (b) is a layer of titanium aluminium nitride represented by the general formula Ti 1-x Al x N z with 0.4≤x≤0.95, and 0.85≤z≤1.15, having a thickness from 0.5 μm to 15 μm, and at least 90% of the Ti 1-x Al x N z of layer (b) has a face-centered cubic (fcc) crystal structure, wherein the multi-layered wear resistant coating includes a layer selected from the group of titanium nitride (TiN), titanium carbonitride (TiCN), and titanium aluminium nitride (TiAlN), said layer being deposited immediately underneath the first h-AlN layer of type (a) and having a columnar grain morphology.

2. The coated cutting tool of claim 1 , wherein the multi-layered wear resistant coating includes one pair of layers (a) and (b).

3. The coated cutting tool of claim 1 , wherein the thickness of the h-AlN layer(s) of the type (a) is from 10 nm to 400 nm.

4. The coated cutting tool of claim 1 , wherein the thickness of the fcc-Ti 1-x Al x N z layer(s) of type (b) is from 1 μm to 8 μm.

5. The coated cutting tool of claim 1 , wherein the thickness ratio of the thickness of the h-AlN layer(s) of the type 1 (a) to the thickness of the Ti 1-x Al x N z layer(s) of type (b) within each pair of layers (a) and (b) with layer (b) being deposited immediately on top of layer (a) is within the range from 0.01 to 0.5.

6. The coated cutting tool of claim 1 , wherein the T 1-x Al x N z layer(s) of type (b) within a pair of layers (a) and (b) with layer (b) being deposited immediately on top of layer (a) has a columnar grain morphology and a preferred crystallographic growth orientation characterized by a texture coefficient TC (111)>1.8, the TC (111) being defined as follows:

TC
⁡

(
111
)

=

I
⁡

(
111
)

I
0

⁡

(
111
)

⁡

[

1
n

⁢

∑

i
=
1

n

⁢

⁢

I
⁡

(
hkl
)

i

I
0

⁡

(
hkl
)

i

]

-
1

wherein
I(111)=measured intensity of the (111) reflection
I 0 (111)=standard intensity of the (111) reflection of the standard powder diffraction data according to the applied JCPDF-card no. 00-046-1200
I(hkl) i =measured intensity of the (hkl) i reflection
I 0 (hkl) i =standard intensity of the (hkl) i reflection of the standard powder diffraction data according to the applied JCPDF-card no. 00-046-1200
n=number of reflections used in the calculation (here: n=4)
(hkl) i the (hkl) i reflections used are: (111), (200), (220) and (311).

7. The coated cutting tool of claim 1 , wherein the layer deposited immediately underneath the first h-AlN layer of the type (a) has a preferred crystallographic growth orientation characterized by a texture coefficient TC (200)>1.8, the TC (200) being defined as follows:

TC
⁡

(
200
)

=

I
⁡

(
200
)

I
0

⁡

(
200
)

⁡

[

1
n

⁢

∑

i
=
1

n

⁢

⁢

I
⁡

(
hkl
)

i

Assignees

• Walter Ag

Inventors

• Stiens Dirk
• Manns Thorsten

Classifications

• C23C16/34 Primary

  Nitrides {(C23C16/303 takes precedence)} · CPC title

• C23C28/44

  characterized by a measurable physical property of the alternating layer or system, e.g. thickness, density, hardness · CPC title

• C23C28/42

  characterized by the composition of the alternating layers · CPC title

• C23C28/044

  coatings specially adapted for cutting tools or wear applications · CPC title

• C23C28/042

  including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides · CPC title