US2014173996A1PendingUtilityA1
Sulfur Containing Alpha-Alumina Coated Cutting Tool
Est. expirySep 16, 2031(~5.1 yrs left)· nominal 20-yr term from priority
C23C 16/403B24D 3/34C23C 16/52C23C 30/005
51
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Claims
Abstract
Cutting tool insert has a substrate and a coating of one or more refractory layers of which at least one layer is an α-Al 2 O 3 layer having thickness of 1 to 25 μm, sulphur content of more than 100 ppm analysed by Secondary Ion Mass Spectroscopy (SIMS), and texture coefficient TC (0 0 12)>4 for the (0 0 12) growth direction. The at least one α-Al 2 O 3 layer is deposited by chemical vapour deposition (CVD) using reaction gases comprising H 2 , CO 2 , AlCl 3 and X, with X being H 2 S, SO 2 , SF 6 , or combinations thereof, and optional additions of N 2 and Ar. The amount of X is at least 1.0 vol-% of the total volume of gases in the reaction chamber. The volume ratio of CO 2 and X in the reaction chamber lies within the range of 1≦CO 2 /X≦7 during deposition of the at least one α-Al 2 O 3 layer.
Claims
exact text as granted — not AI-modified1 . A cutting tool insert consisting of:
a substrate of cemented carbide, cermet, ceramics, steel or a superhard material; and a coating with a total thickness of 5 to 40 μm, the coating consisting of one or more refractory layers of which at least one layer is an α-Al 2 O 3 layer having a thickness of 1 to 25 μm, wherein the at least one α-Al 2 O 3 layer has a sulphur content of more than 100 ppm analysed by Secondary Ion Mass Spectroscopy (SIMS) and the at least one α-Al 2 O 3 layer has a texture coefficient TC (0 0 12)>4 for the (0 0 12) growth direction, the TC (0 0 12) being defined as follows:
TC
(
0
0
12
)
=
I
(
0
0
12
)
I
0
(
0
0
12
)
[
1
n
∑
n
-
1
n
I
(
hkl
)
I
0
(
hkl
)
]
-
1
(hkl)=measured intensity of the (hkl) reflection
I 0 (hkl)=standard intensity of the standard powder diffraction data according to JCPDF-card no. 42-1468
n=number of reflections used in the calculation, whereby the (hkl) reflections used are: (012), (104), (110), (113), (116), (300) and (0 0 12).
2 . The cutting tool insert of claim 1 wherein the at least one α-Al 2 O 3 layer has a sulphur content of more than 120 ppm analysed by SIMS.
3 . The cutting tool insert of claim 1 , wherein the coating comprises, in addition to the at least one α-Al 2 O 3 layer, one or more refractory layers consisting of carbide, nitride, carbonitride, oxycarbonitride or borocarbonitride of one or more of Ti, Zr, V and Hf, or combinations thereof deposited using CVD or MT-CVD, having a thickness of from 0.5 to 20 μm.
4 . The cutting tool insert of claim 1 , wherein
a) the uppermost layer of the coating is the α-Al 2 O 3 layer or b) the uppermost layer of the coating is a layer of carbide, nitride, carbonitride or oxycarbnitride of one or more of Ti, Zr, V and Hf, or combinations thereof, having a thickness of from 0.5 to 3 μm and being deposited atop of the α-Al 2 O 3 layer or c) surface areas of the cutting tool insert comprise the α-Al 2 O 3 layer as the uppermost layer whereas the remaining surface areas of the cutting tool insert comprise as the uppermost layer a layer of carbide, nitride, carbonitride or oxycarbnitride of one or more of Ti, Zr, V and Hf, or combinations thereof, having a thickness of from 0.5 to 3 μm and being deposited atop of the α-Al 2 O 3 layer.
5 . The cutting tool insert of claim 1 wherein the substrate consists of cemented carbide optionally 0.3-10 wt-% cubic carbides of the metals from groups IVb, Vb and VIb of the periodic table and balance WC.
6 . The cutting tool insert of claim 1 wherein the substrate consists of cemented carbide comprising a binder phase enriched surface zone having a thickness of 5 to 30 μm from the substrate surface, the binder phase enriched surface zone having a Co content that is at least 1.5 times higher than in the core of the substrate and having a content of cubic carbides that is less than 0.5 times the content of cubic carbides in the core of the substrate.
7 . The cutting tool insert of claim 1 wherein the at least one α-Al 2 O 3 layer has a texture coefficient TC (0 0 12)>5, for the (0 0 12) growth direction.
8 . A method of manufacturing a cutting tool insert of claim 1 , comprising:
depositing said at least one α-Al 2 O 3 layer by chemical vapour deposition (CVD), wherein the reaction gas of the CVD process comprises H 2 , CO 2 , AlCl 3 and X, with X being H 2 S, SO 2 , SF 6 , or combinations thereof, and optional additions of N 2 and Ar, wherein the X is present in the reaction gas mixture in an amount of at least 1.0 vol-% of the total volume of gases in the CVD reaction chamber, and wherein the volume ratio of CO 2 and X in the CVD reaction chamber lies within the range of 1≦CO 2 /X≦7 during deposition of the at least one α-Al 2 O 3 layer.
9 . The method of claim 8 , wherein the volume proportion of the component X or the combination of components X is present in the reaction gas mixture during deposition of the at least one α-Al 2 O 3 layer in an amount of at least 1.2 vol-% of the total volume of gases in the CVD reaction chamber.
10 . The method of claim 8 , wherein the volume ratio of CO 2 and X in the CVD reaction chamber lies within the range of 2≦CO 2 /X≦6 during deposition of the at least one α-Al 2 O 3 layer.
11 . The method of any of claim 8 , wherein the volume ratio of CO 2 /AlCl 3 in the CVD reaction chamber is equal or smaller than 1.5 and/or the volume ratio of AlCl 3 /HCl in the CVD reaction chamber is equal or smaller than 1, during deposition of the at least one α-Al 2 O 3 layer.
12 . The method of claim 8 , wherein the CVD process during deposition of the at least one α-Al 2 O 3 layer is conducted at a temperature in the range of 850 to 1050° C. and/or the CVD process during deposition of the at least one α-Al 2 O 3 layer is conducted at a reaction gas pressure in the range 50 to 120 mbar.
13 . The method of claim 8 , wherein the component X in the CVD process is H 2 S or SO 2 or a combination of H 2 S and SO 2 , whereby, if the component X in the CVD process is a combination of H 2 S and SO 2 , the volume proportion of SO 2 does not exceed 20% of the volume amount of H 2 S.
14 . The method of any of claim 8 , wherein the reaction gas of the CVD process comprises additions of N 2 and/or Ar in a volume amount in the range of 4 to 20 vol % of the total volume of gases in the CVD reaction chamber.
15 . The cutting tool insert of claim 2 wherein at least one α-Al 2 O 3 layer has a sulphur content of more than 150 ppm analysed by SIMS.
16 . The cutting tool insert of claim 7 wherein the at least one α-Al 2 O 3 layer has a texture coefficient TC (0 0 12)>6 for the (0 0 12) growth direction.
17 . The method of claim 9 , wherein the volume proportion of the component X or the combination of components X is present in the reaction gas mixture during deposition of the at least one α-Al 2 O 3 layer in an amount of at least 1.5 vol-% of the total volume of gases in the CVD reaction chamber.
18 . The method of claim 12 , wherein the temperature is in the range of 980 to 1050° C.
19 . The method of claim 12 , wherein the temperature is in the range of 1000 to 1020° C.
20 . The method of claim 12 , wherein the reaction gas pressure is in the range 50 to 150 mbar.Join the waitlist — get patent alerts
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