US2012015148A1PendingUtilityA1
Alumina layer with enhanced texture
Est. expirySep 27, 2025(expired)· nominal 20-yr term from priority
Inventors:Sakari Ruppi
C23C 30/005C23C 16/403C23C 16/30C04B 41/87C04B 41/5031C23C 16/36Y10T428/266B23B 27/14Y10T428/252Y10T428/24975Y10T428/265Y10T428/24413B23B 27/00
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Claims
Abstract
The present invention relates to a coated cutting tool insert comprising a substrate and a coating to be used in metal machining. The hard and wear resistant coating exhibits an excellent adhesion to the substrate covering all functional parts thereof. The coating is composed of one or more refractory layers of which at least one layer is α-Al 2 O 3 showing a strong growth texture along <001>. The α-Al 2 O 3 layer has a thickness ranging from 1 to 20 μm and is composed of columnar grains with a length/width ratio of 2 to 15. The layer is characterised by a strong (006) diffraction peak, measured using XRD, and by low intensity of (012), (104), (113) (024) and (116) diffraction peaks. The <001>textured α-Al 2 O 3 layers is deposited in a temperature range of 750-1000° C. The texture is controlled by a specific nucleation procedure combined with the use of sulphur- and fluorine containing dopants.
Claims
exact text as granted — not AI-modified1 . A cutting tool insert comprising a substrate at least partially coated with a coating having a total thickness of from about 5 to about 40 comprising one or more refractory layers of which at least one layer of which is an α-alumina layer wherein said α-alumina layer comprises columnar α-Al 2 O 3 grains with a <001> growth direction with texture coefficients
a) TC(006)>1.4, preferably >3.0 and most preferably >4.0.
the texture coefficient TC(hkl) being defined as
TC
(
hkl
)
=
I
(
hkil
)
I
0
(
hkil
)
{
1
n
∑
I
(
hkil
)
I
0
(
hkil
)
}
-
1
wherein
I(hkl)=measured intensity of the (hkl) reflection
I 0 (hkl)=standard intensity according to JCPDS card no 46-1212
n=number of reflections used in the calculation
(hkl) reflections used are: (012), (104), (110), (006), (113) and (116).
2 . Cutting tool insert according to claim 1 , wherein said at least one layer is an as deposited layer of α-alumina.
3 . Cutting tool insert according to claim 1 , wherein said alumina columnar grains have a length/width ratio from about 2 to about 15.
4 . Cutting tool insert according to claim 1 , wherein said substrate comprises cemented carbide with a binder phase enriched surface zone, CBN or sintered CBN alloy.
5 . Cutting tool insert according to claim 1 , wherein the coating comprises a first layer adjacent the body of CVD Ti(C,N), CVD TiN, CVD TiC, MTCVD Ti(C,N), MTCVD Zr(C,N), MTCVD Ti(B,C.N), CVD HfN or combinations thereof preferably of Ti(C,N) having a thickness of from 1 to 20 μm, and said α-Al 2 O 3 layer adjacent said first layer having a thickness of from about 1 to about 40 μm, preferably from about 1 to about 20 μm, most preferably from about 1 to about 10 μm.
6 . Cutting tool insert according to claim 1 , wherein the α-Al 2 O 3 layer is the uppermost layer.
7 . Cutting tool insert according to claim 1 , wherein a layer of carbide, nitride, carbonitride or carboxynitride of one or more of Ti, Zr and Hf, having a thickness of from about 0.5 to 3 μm, preferably from about 0.5 to about 1.5 μm atop the α-Al 2 O 3 layer.
8 . Cutting tool insert according to claim 1 , wherein a layer of carbide, nitride, carbonitride or carboxynitride of one or more of Ti, Zr and Hf, having a thickness of from about 1 to 20 μm, preferably 2 to 8 μm atop the α-Al 2 O 3 layer.
9 . Cutting tool insert according to claim 1 , wherein a layer of κ-Al 2 O 3 or γ-Al 2 O 3 atop the α-Al 2 O 3 with a thickness of from 0.5 to 10 μm, preferably from 1 to 5 μm.
10 . Cutting tool insert according to claim 1 , wherein a layer of TiN between the substrate and said first layer with a thickness of <3 μm, preferably 0.5-2 μm.
11 . Cutting tool insert according to claim 1 , wherein said coating has a total thickness of from about 5 to about 25 μm.
12 . Cutting tool insert according to claim 1 , wherein said alumina columnar grains have a length/width ratio from about 5 to about 10.
13 . Cutting tool insert according to claim 1 , wherein said first layer adjacent the body having a thickness of from 1 to 10 μm.
14 . Cutting tool insert according to claim 1 , wherein said α-Al 2 O 3 layer adjacent said first layer has a thickness of from about 1 to about 20 μm.
15 . Cutting tool insert according to claim 1 , wherein said α-Al 2 O 3 layer adjacent said first layer has a thickness of from about 1 to about 10 μm.
16 . A cutting tool insert comprising a substrate at least partially coated with a coating having a total thickness of from about 5 to about 40 μm, preferably 5-25 μm comprising one or more refractory layers of which at least one layer of which is an α-alumina layer wherein said α-alumina layer comprises columnar α-Al 2 O 3 grains with a <001> growth direction with texture coefficients
a) TC(006)>1.4, preferably >3.0 and most preferably >4.0.
the texture coefficient TC(hkl) being defined as
TC
(
hkl
)
=
I
(
hkil
)
I
0
(
hkil
)
{
1
n
∑
I
(
hkil
)
I
0
(
hkil
)
}
-
1
wherein
I(hkl)=measured intensity of the (hid) reflection
I 0 (hkl)=standard intensity according to JCPDS card no 46-1212
n=number of reflections used in the calculation
(hkl) reflections used are: (012), (104), (110), (006), (113) and (116), and
wherein said α-alumina layer is formed by controlling both the nucleation and growth of α-alumina using sulphur-containing and at least one fluorine-containing precursor.
17 . Cutting tool insert according to claim 16 , wherein said at least one sulphur-containing precursor is selected from the group consisting of H 2 S, SF 6 , SO 2 , SF 6 and mixtures thereof.
18 . A method of making an α-Al 2 O 3 layer on a substrate, comprising the steps of:
nucleating said alumina in a temperature range of from about 750 to about 1000° C., and controlling both the nucleation and growth of α-alumina using sulphur-containing and at least one fluorine-containing precursor.
19 . Method according to claim 18 , wherein said at least one sulphur-containing precursor is selected from the group consisting of H 2 S, SF 6 , SO 2 , SF 6 and mixtures thereof.
20 . Method according to claim 18 , wherein said at least one sulphur-containing precursor comprises a mixture of H 2 S and SF 6 .Join the waitlist — get patent alerts
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