COATED CUTTING TOOL

Abstract

A coated cutting tool having a substrate and a coating is provided. The coating includes a nano-multilayer of alternating nanolayers of a first nanolayer type being Ti.sub.1-xAl.sub.xN, 0.35?x<0.67, a second nanolayer type being Ti.sub.1-ySi.sub.yN, 0.10?y?0.25, and a third nanolayer type being Ti.sub.1-zAl.sub.zN, 0.70?z?0.90. The nano-multilayer has a thickness from about 0.5 to about 10 ?m. The average nanolayer thickness of each of the nanolayer types Ti.sub.1-xAl.sub.xN (9), Ti.sub.1-ySi.sub.yN, and Ti.sub.1-zAl.sub.zN in the nano-multilayer being from 1 to 30 nm.

Claims

1. A coated cutting tool comprising: a substrate and a coating disposed on the substrate, wherein the coating includes a nano-multilayer of alternating nanolayers of a first nanolayer type being Ti.sub.1-xAl.sub.xN, 0.35?x<0.67, a second nanolayer type being Ti.sub.1-ySi.sub.yN, 0.10?y?0.25, and a third nanolayer type being Ti.sub.1-zAl.sub.zN, 0.70?z?0.90, wherein a thickness of the nano-multilayer is from about 0.5 to about 10 ?m, and wherein an average nanolayer thickness of each of the nanolayer types Ti.sub.1-xAl.sub.xN, Ti.sub.1-ySi.sub.yN, and Ti.sub.1-zAl.sub.zN in the nano-multilayer is from 1 to 30 nm.

2. The coated cutting tool according to claim 1, wherein there is a ratio in the nano-multilayer between the sum of thickness of all of each nanolayer types Ti.sub.1-xAl.sub.xN:Ti.sub.1-ySi.sub.yN:Ti.sub.1-zAl.sub.zN, being a:b:c, wherein 0.5<a<3, 0.5<b<3, 0.5<c<3.

3. The coated cutting tool according to claim 1, wherein for the first nanolayer type of Ti.sub.1-xAl.sub.xN 0.40?x?0.67.

4. The coated cutting tool according to claim 1, wherein for the second nanolayer type of Ti.sub.1-ySi.sub.yN 0.13?y?0.23.

5. The coated cutting tool according to claim 1, wherein for the third nanolayer type of Ti.sub.1-zAl.sub.zN 0.70<z?0.85.

6. The coated cutting tool according to claim 1, wherein the average nanolayer thickness in the nano-multilayer, of each of the nanolayer types Ti.sub.1-xAl.sub.xN, Ti.sub.1-ySi.sub.yN, and Ti.sub.1-zAl.sub.zN in the nano-multilayer, is from 1 to 20 nm.

7. The coated cutting tool according to claim 1, wherein a ratio of average nanolayer thickness in the nano-multilayer between any one of the nanolayer types Ti.sub.1-xAl.sub.xN, Ti.sub.1-ySi.sub.yN, and Ti.sub.1-zAl.sub.zN to any of a remaining two of the nanolayer types Ti.sub.1-xAl.sub.xN, Ti.sub.1-ySi.sub.yN, and Ti.sub.1-zAl.sub.zN in the nano-multilayer is of from 0.1 to 10.

8. The coated cutting tool according to claim 1, wherein within a sequence of 10 consecutive nanolayers in the nano-multilayer all of the nanolayer types Ti.sub.1-xAl.sub.xN, Ti.sub.1-ySi.sub.yN, and Ti.sub.1-zAl.sub.zN are present.

9. The coated cutting tool according to claim 1, wherein the thickness of the nano-multilayer is from about 1 to about 8 ?m.

10. The coated cutting tool according to claim 1, wherein the coating includes an inner layer of TiN or (Ti,Al)N located below the nano-multilayer and closest to the substrate, the inner layer having a thickness of from about 0.1 to about 3 ?m.

11. The coated cutting tool according to claim 10, wherein the inner layer is Ti.sub.1-tAl.sub.tN, 0.35?t?0.70.

12. The coated cutting tool according to claim 10, wherein the inner layer is a (Ti,Al)N layer being a (Ti,Al)N nano-multilayer of alternating nanolayers of Ti.sub.1-uAl.sub.uN, 0.35?u<0.67 and Ti.sub.1-vAl.sub.vN, 0.70?v?0.90.

13. The coated cutting tool according to claim 1, wherein the substrate of the coated cutting tool is selected from the group of cemented carbide, cermet, ceramic, cubic boron nitride and high speed steel.

14. The coated cutting tool according to claim 1, wherein the coated cutting tool is a cutting tool insert, a drill, or a solid end-mill, for metal machining.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0030] FIG. 1 shows a schematic view of one embodiment of a cutting tool being a milling insert.

[0031] FIG. 2 shows a schematic view of one embodiment of a cutting tool being a turning insert.

[0032] FIG. 3 shows a schematic view of a cross section of an embodiment of the coated cutting tool of the present invention showing a substrate and a coating comprising different layers.

DETAILED DESCRIPTION OF EMBODIMENTS IN DRAWINGS

[0033] FIG. 1 shows a schematic view of one embodiment of a cutting tool (1) having a rake face 2 and flank faces 3 and a cutting edge 4. The cutting tool 1 is in this embodiment a milling insert. FIG. 2 shows a schematic view of one embodiment of a cutting tool 1 having a rake face 2 and flank face 3 and a cutting edge 4. The cutting tool 1 is in this embodiment a turning insert. FIG. 3 shows a schematic view of a cross section of an embodiment of the coated cutting tool of the present invention having a substrate 5 and a coating 6. The coating 6 consisting of a first (Ti,Al)N innermost layer 7 followed by a nano-multilayer 8 of alternating nanolayers 9, 10 and 11 being Ti.sub.1-xAl.sub.xN, Ti.sub.1-ySi.sub.yN, and Ti.sub.1-zAl.sub.zN.

DETAILED DESCRIPTION OF EMBODIMENTS

[0034] In one embodiment, there is a ratio in the nano-multilayer 8 between the sum of nanolayer thicknesses of each nanolayer type 9, 10, 11, Ti.sub.1-xAl.sub.xN:Ti.sub.1-ySi.sub.yN:Ti.sub.1-zAl.sub.zN, in the nano-multilayer 8, a:b:c, 1.5<a<2.5, 0.75<b<1.25, 0.75<c<1.25, preferably 1.75<a<2.25, 0.9<b<1.1, 0.9<c<1.1. In this embodiment the nano-multilayer 8 suitably comprises a repeating sequence of consecutive nanolayers of the first nanolayer type 9, Ti.sub.1-xAl.sub.xN, the second nanolayer type 10, Ti.sub.1-ySi.sub.yN, and the third nanolayer type 11, Ti.sub.1-zAl.sub.zN, in the order Ti.sub.1-xAl.sub.xN/Ti.sub.1-zAl.sub.zN/Ti.sub.1-xAl.sub.xN/Ti.sub.1-ySi.sub.yN. The nano-multilayer 8 is suitably composed of (Ti.sub.1-xAl.sub.xN/Ti.sub.1-zAl.sub.zN/Ti.sub.1-xAl.sub.xN/Ti.sub.1-ySi.sub.yN . . . ).sub.m, m=15?1500, suitably m=30?800.

[0035] In a further embodiment, there is a ratio in the nano-multilayer 8 between the sum of nanolayer thicknesses of each nanolayer type 9, 10, 11, Ti.sub.1-xAl.sub.xN:Ti.sub.1-ySi.sub.yN:Ti.sub.1-zAl.sub.zN, in the nano-multilayer 8, a:b:c, 0.75<a<1.25, 1.5<b<2.5, 0.75<c<1.25, preferably 0.9<a<1.1, 1.75<b<2.25, 0.9<c<1.1. In this embodiment the nano-multilayer 8 suitably comprises a repeating sequence of consecutive nanolayers of the first nanolayer type 9, Ti.sub.1-xAl.sub.xN, the second nanolayer type 10, Ti.sub.1-ySi.sub.yN, and the third nanolayer type 11, Ti.sub.1-zAl.sub.zN, in the order Ti.sub.1-xAl.sub.xN/Ti.sub.1-ySi.sub.yN/Ti.sub.1-zAl.sub.zN/Ti.sub.1-ySi.sub.yN. The nano-multilayer (8) is suitably composed of (Ti.sub.1-xAl.sub.xN/Ti.sub.1-ySi.sub.yN/Ti.sub.1-zAl.sub.zN/Ti.sub.1-ySi.sub.yN).sub.n, n=15?1500, suitably n=30?800.

[0036] In a further embodiment, there is a ratio in the nano-multilayer 8 between the sum of nanolayer thicknesses of each nanolayer type 9, 10, 11, Ti.sub.1-xAl.sub.xN:Ti.sub.1-ySi.sub.yN:Ti.sub.1-zAl.sub.zN, in the nano-multilayer 8, a:b:c, 0.75<a<1.25, 0.75<b<1.25, 1.5<c<2.5, preferably 0.9<a<1.1, 0.9<b<1.1, 1.75<c<2.25. In this embodiment the nano-multilayer 8 suitably comprises a repeating sequence of consecutive nanolayers of the first nanolayer type 9, Ti.sub.1-xAl.sub.xN, the second nanolayer type 10, Ti.sub.1-ySi.sub.yN, and the third nanolayer type 11, Ti.sub.1-zAl.sub.zN, in the order Ti.sub.1-zAl.sub.zN/Ti.sub.1-xAl.sub.xN/Ti.sub.1-zAl.sub.zN/Ti.sub.1-ySi.sub.yN. The nano-multilayer 8 is suitably composed of (Ti.sub.1-zAl.sub.zN/Ti.sub.1-xAl.sub.xN/Ti.sub.1-zAl.sub.zN/Ti.sub.1-ySi.sub.yN).sub.p, p=15?1500, suitably p=30?800.

[0037] In a further embodiment, there is a ratio in the nano-multilayer 8 between the sum of nanolayer thicknesses of each nanolayer type 9, 10, 11, Ti.sub.1-xAl.sub.xN:Ti.sub.1-ySi.sub.yN:Ti.sub.1-zAl.sub.zN, in the nano-multilayer 8, a:b:c, 0.75<a<1.25, 0.75<b<1.25, 0.75<c<1.25, preferably 0.9<a<1.1, 0.9<b<1.1, 0.9<c<1.1. In this embodiment the nano-multilayer 8 suitably comprises a repeating sequence of consecutive nanolayers of the first nanolayer type 9, Ti.sub.1-xAl.sub.xN, the second nanolayer type 10, Ti.sub.1-ySi.sub.yN, and the third nanolayer type 11, Ti.sub.1-zAl.sub.zN, in the order Ti.sub.1-xAl.sub.xN/Ti.sub.1-ySi.sub.yN/Ti.sub.1-zAl.sub.zN. The nano-multilayer 8 is suitably composed of (Ti.sub.1-xAl.sub.xN/Ti.sub.1-ySi.sub.yN/Ti.sub.1-zAl.sub.zN).sub.q, q=20?2000, suitably q=40?1000.

[0038] In a further embodiment, the coating 6 comprises an inner layer 7, preferably closest to the substrate 5, of (Ti,Al)N below the nano-multilayer 8 wherein the inner layer 7 is a (Ti,Al)N layer being a (Ti,Al)N nano-multilayer of alternating nanolayers of Ti.sub.1-uAl.sub.uN, 0.35?u<0.67, suitably 0.40?u?0.67, preferably 0.45?u?0.62 and Ti.sub.1-vAl.sub.vN, 0.70?v?0.90, suitably 0.70?v?0.80.

[0039] The average nanolayer thickness of the Ti.sub.1-uAl.sub.uN layers in the (Ti,Al)N nano-multilayer is suitably from 1 to 30 nm, preferably from 1 to 20 nm, most preferably from 2 to 10 nm. The thickness of this inner layer 7 is suitably from about 0.1 to about 3 ?m, preferably from about 0.5 to about 2 ?m.

EXAMPLES

Example 1 (Invention)

[0040] Coated cutting tools were provided comprising a nano-multilayer of Ti.sub.0.85Si.sub.0.15N, Ti.sub.0.50Al.sub.0.50N and Ti.sub.0.20Al.sub.0.80N nanolayers deposited on sintered cemented carbide cutting tool insert blanks of the geometries CNMG120408MM and R390-11T308M-PM. The composition of the cemented carbide was 10 wt % Co, 0.4 wt % Cr and rest WC. The cemented carbide blanks were coated by cathodic arc evaporation in a vacuum chamber comprising four arc flanges, each flange comprising several cathode evaporators. Targets of Ti.sub.0.50Al.sub.0.50 were mounted in the evaporators in two of the flanges opposite each other. The remaining targets Ti.sub.0.85Si.sub.0.15 and Ti.sub.0.20Al.sub.0.80 were mounted in the evaporators in the two remaining flanges opposite each other. The targets were circular and planar with a diameter of 100 mm available on the open market. Suitable target technology packages for arc evaporation are available from suppliers on the market such as IHI Hauzer Techno Coating B.V., Kobelco (Kobe Steel Ltd.) and Oerlikon Balzers.

[0041] The uncoated blanks were mounted on pins that undergo a three-fold rotation in the PVD chamber.

[0042] The chamber was pumped down to high vacuum (less than 10.sup.-2 Pa) and heated to about 450-550? C. by heaters located inside the chamber. The blanks were then etched for 60 minutes in an Ar plasma.

[0043] At first, an innermost layer of Ti.sub.0.50Al.sub.0.50N was deposited by only using the Ti.sub.0.50Al.sub.0.50 targets.

[0044] The chamber pressure (reaction pressure) was set to 4 Pa of N.sub.2 gas, and a DC bias voltage of ?50 V (relative to the chamber walls) was applied to the blank assembly. The cathodes were run in an arc discharge mode at a current of 150 A (each) for 70 minutes (2 flanges). The table rotational speed was 5 rpm. A layer of Ti.sub.0.50Al.sub.0.50N having a thickness of about 1.4 ?m was deposited on the blanks.

[0045] Then, the nano-multilayer was deposited by using all mounted targets.

[0046] The chamber pressure (reaction pressure) was set to 4 Pa of N.sub.2 gas, and a DC bias voltage of ?70 V (relative to the chamber walls) was applied to the blank assembly. The cathodes were run in an arc discharge mode at a current of 150 A (each) for 35 minutes (4 flanges). The table rotational speed was 5 rpm. A nano-multilayer coating having a thickness of about 1.4 ?m was deposited on the blanks.

[0047] The rotational speed correlates to a certain period thickness and it was concluded that a table rotational speed of 5 rpm for the current deposition rate and equipment used correlates to an average individual nanolayer thickness of each of the nanolayers Ti.sub.0.50Al.sub.0.50N, Ti.sub.0.85Si.sub.0.15N and Ti.sub.0.20Al.sub.0.80N of about 2 nm. The number of nanolayers in the nano-multilayer is about 700.

[0048] The nano-multilayer comprises a repeating sequence of consecutive nanolayers in the order Ti.sub.0.50Al.sub.0.50N/Ti.sub.0.20Al.sub.0.80N/Ti.sub.0.50Al.sub.0.50N/Ti.sub.0.85Si.sub.0.15N.

[0049] Finally, an outermost layer of Ti.sub.0.85Si.sub.0.15N, in order to obtain an even colour between the individual coated cutting tools made, was deposited by only using the Ti.sub.0.85Si.sub.0.15 target. All deposition parameters were the same as for depositing the previous layer, except for the bias being ?60 V and the cathodes were run for 10 minutes (1 flange). A layer of Ti.sub.0.85Si.sub.0.15N was deposited to a thickness of about 0.2 ?m.

[0050] In the nano-multilayer, the ratio of the sum of nanolayer thicknesses of each of the nanolayers Ti.sub.0.50Al.sub.0.50N, Ti.sub.0.85Si.sub.0.15N, Ti.sub.0.20Al.sub.0.80N, respectively, i.e., Ti.sub.0.50Al.sub.0.50N: Ti.sub.0.85Si.sub.0.15N: Ti.sub.0.20Al.sub.0.80N, is about 2:1:1. The ratio is estimated from a deposition rate from each target assumed to be the same, the rotation during deposition and the deposition time.

[0051] The coated cutting tools were called Sample 1 (invention).

Example 2

[0052] Coated cutting tools were provided comprising a nano-multilayer of Ti.sub.0.85Si.sub.0.15N, Ti.sub.0.50Al.sub.0.50N and Ti.sub.0.20Al.sub.0.80N nanolayers deposited on sintered cemented carbide cutting tool insert blanks of the geometries CNMG120408MM and R390-11T308M-PM. The composition of the cemented carbide was 10 wt % Co, 0.4 wt % Cr and rest WC. The cemented carbide blanks were coated by cathodic arc evaporation in a vacuum chamber comprising four arc flanges, each flange comprising several cathode evaporators. Targets of Ti.sub.0.50Al.sub.0.50 were mounted in the evaporators in two of the flanges opposite each other. The remaining targets Ti.sub.0.85Si.sub.0.15 and Ti.sub.0.20Al.sub.0.80 were mounted in the evaporators in the two remaining flanges opposite each other. The targets were circular and planar with a diameter of 100 mm available on the open market. Suitable target technology packages for arc evaporation are available from suppliers on the market such as IHI Hauzer Techno Coating B.V., Kobelco (Kobe Steel Ltd.) and Oerlikon Balzers.

[0053] The uncoated blanks were mounted on pins that undergo a three-fold rotation in the PVD chamber.

[0054] The chamber was pumped down to high vacuum (less than 10.sup.-2 Pa) and heated to about 450-550? C. by heaters located inside the chamber. The blanks were then etched for 60 minutes in an Ar plasma.

[0055] At first, an innermost layer of Ti.sub.0.50Al.sub.0.50N was deposited by only using the Ti.sub.0.50Al.sub.0.50 targets.

[0056] The chamber pressure (reaction pressure) was set to 4 Pa of N.sub.2 gas, and a DC bias voltage of ?50 V (relative to the chamber walls) was applied to the blank assembly. The cathodes were run in an arc discharge mode at a current of 150 A (each) for 70 minutes (2 flanges). The table rotational speed was 5 rpm. A layer of Ti.sub.0.50Al.sub.0.50N having a thickness of about 1.4 ?um was deposited on the blanks.

[0057] Then, the nano-multilayer was deposited by alternating the use of the Ti.sub.0.85Si.sub.0.15 and Ti.sub.0.20Al.sub.0.80 targets, creating a first sequence of a Ti.sub.0.85Si.sub.0.15N/Ti.sub.0.20Al.sub.0.80N nano-multilayer of about 35 nm thickness. The table rotational speed was 5 rpm. Then only the Ti.sub.0.50Al.sub.0.50 targets were used creating a Ti.sub.0.50Al.sub.0.50N layer of about 35 nm thickness. This procedure was repeated until 20 sequences of a nano-multilayer sequence of nanolayers Ti.sub.0.85Si.sub.0.15N and Ti.sub.0.20Al.sub.0.80N combined with a monolayer of Ti.sub.0.50Al.sub.0.50N was completed. The total thickness of the deposited nano-multilayer was about 1.4 ?m.

[0058] The chamber pressure (reaction pressure) was set to 4 Pa of N.sub.2 gas, and a DC bias voltage of ?40 V (relative to the chamber walls) was applied to the blank assembly when using the Ti.sub.0.85Si.sub.0.15 and Ti.sub.0.20Al.sub.0.80 targets and a DC bias voltage of ?80 V (relative to the chamber walls) when using the Ti.sub.0.50Al.sub.0.50 targets. The cathodes were run in an arc discharge mode at a current of 150 A (each) for 70 minutes (2 flanges at a time). The table rotational speed was 5 rpm. A nano-multilayer coating having a thickness of about 1.4 ?m was deposited on the blanks.

[0059] The rotational speed correlates to a certain period thickness and it was concluded that a table rotational speed of 5 rpm for the current deposition rate and equipment used correlates to an average individual nanolayer thickness of each of the nanolayers Ti.sub.0.85Si.sub.0.15N and Ti.sub.0.20Al.sub.0.80N of about 2 nm.

[0060] Finally, an outermost layer of Ti.sub.0.85Si.sub.0.15N, in order to obtain an even colour between the individual coated cutting tools made, was deposited by only using the Ti.sub.0.85Si.sub.0.15 target. All deposition parameters were the same as for depositing the previous layer, except for the bias being ?60 V and the cathodes were run for 10 minutes (1 flange). A layer of Ti.sub.0.85Si.sub.0.15N was deposited to a thickness of about 0.2 ?m.

[0061] The coated cutting tools were called Sample 2 (comparative).

Example 3

[0062] Three different sets of samples of coated cutting tools were provided comprising a nano-multilayer of Ti.sub.0.80Si.sub.0.20N, Ti.sub.0.40Al.sub.0.60N nanolayers and, respectively, one of a high-Al Ti.sub.0.25Al.sub.0.75N, Ti.sub.0.15Al.sub.0.85N or Ti.sub.0.05Al.sub.0.95N nanolayers deposited on sintered cemented carbide cutting tool insert blanks of the geometries CNMG120408MM and R390-11T308M-PM. The composition of the cemented carbide was 10 wt % Co, 0.4 wt % Cr and rest WC. The cemented carbide blanks were coated by cathodic arc evaporation in a vacuum chamber comprising four arc flanges, each flange comprising several cathode evaporators. Targets of Ti.sub.0.80Si.sub.0.20 were mounted in the evaporators in two of the flanges opposite each other. The remaining targets Ti.sub.0.40Al.sub.0.60 and the high-Al (Ti,Al) target used (Ti.sub.0.25Al.sub.0.75, Ti.sub.0.15Al.sub.0.85 or Ti.sub.0.05Al.sub.0.95, respectively, in the three differents runs) were mounted in the evaporators in the two remaining flanges opposite each other. The targets were circular and planar with a diameter of 100 mm available on the open market. Suitable target technology packages for arc evaporation are available from suppliers on the market such as IHI Hauzer Techno Coating B.V., Kobelco (Kobe Steel Ltd.) and Oerlikon Balzers.

[0063] The uncoated blanks were mounted on pins that undergo a three-fold rotation in the PVD chamber.

[0064] The chamber was pumped down to high vacuum (less than 10.sup.-2 Pa) and heated to about 450-550? C. by heaters located inside the chamber. The blanks were then etched for 60 minutes in an Ar plasma.

[0065] At first, an innermost layer of Ti.sub.0.40Al.sub.0.60N was deposited by only using the Ti.sub.0.40Al.sub.0.60 target. The chamber pressure (reaction pressure) was set to 4 Pa of N.sub.2 gas, and a DC bias voltage of ?70 V (relative to the chamber walls) was applied to the blank assembly. The cathodes were run in an arc discharge mode at a current of 150 A (each) for 100 minutes (1 flange). The table rotational speed was 5 rpm. A layer of Ti.sub.0.40Al.sub.0.60N having a thickness of about 1 ?m was deposited on the blanks.

[0066] Then, the nano-multilayer was deposited by using all mounted targets.

[0067] The chamber pressure (reaction pressure) was set to 4 Pa of N.sub.2 gas, and a DC bias voltage of ?100 V (relative to the chamber walls) was applied to the blank assembly. The cathodes were run in an arc discharge mode at a current of 150 A (each) for 50 minutes (4 flanges). The table rotational speed was 5 rpm. A nano-multilayer coating having a thickness of about 2 ?m was deposited on the blanks.

[0068] Since the table rotational speed correlates to a certain period thickness and it was concluded that a table rotational speed of 5 rpm for the current deposition rate and equipment used correlates to an average individual nanolayer thickness of each of the nanolayers Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.80Si.sub.0.20N and also Ti.sub.0.25Al.sub.0.75N, Ti.sub.0.15Al.sub.0.85N and Ti.sub.0.05Al.sub.0.95N, respectively, in the three different nano-multilayers made of about 2 nm. The number of nanolayers in all three different sets of nano-multilayers is about 1000.

[0069] The nano-multilayer of the first set of samples comprises a repeating sequence of consecutive nanolayers in the order Ti.sub.0.40Al.sub.0.60N/Ti.sub.0.80Si.sub.0.20N/Ti.sub.0.25Al.sub.0.75N/Ti.sub.0.80Si.sub.0.20N. The nano-multilayer of the second set of samples comprises a repeating sequence of consecutive nanolayers in the order Ti.sub.0.40Al.sub.0.60N/Ti.sub.0.80Si.sub.0.20N/Ti.sub.0.15Al.sub.0.85N/Ti.sub.0.80Si.sub.0.20N. The nano-multilayer of the third set of samples comprises a repeating sequence of consecutive nanolayers in the order Ti.sub.0.40Al.sub.0.60N/Ti.sub.0.80Si.sub.0.20N/Ti.sub.0.05Al.sub.0.95N/Ti.sub.0.80Si.sub.0.20N.

[0070] Finally, an outermost layer, in order to obtain an even colour between the individual coated cutting tools made, was deposited by only using the respective high-Al (Ti,Al) target used when depositing the respective nano-multilayer for the three different sets of samples. All deposition parameters were the same as for depositing the previous layer, except for the bias being ?100 V and the cathodes were run for 10 minutes (1 flange). A layer of Ti.sub.0.25Al.sub.0.75N, Ti.sub.0.15Al.sub.0.85N or Ti.sub.0.05Al.sub.0.95N was deposited, respectively, on the three different sets of samples, to a thickness of about 0.2 ?m.

[0071] In the nano-multilayer, the thickness ratio sum of thicknesses of each of the nanolayers Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.85Si.sub.0.15N, and the one of Ti.sub.0.25Al.sub.0.75N, Ti.sub.0.15Al.sub.0.85N, and Ti.sub.0.05Al.sub.0.95N, respectively, i.e., Ti.sub.0.40Al.sub.0.60N: Ti.sub.0.85Si.sub.0.15N: (Ti.sub.0.25Al.sub.0.75N, Ti.sub.0.15Al.sub.0.85N, or Ti.sub.0.05Al.sub.0.95N), is about 1:2:1. The ratio is estimated from a deposition rate from each target assumed to be the same, the rotation during deposition and the deposition time.

[0072] The coated cutting tools made were called: [0073] Sample 3 for the coated cutting tools where the nano-multilayer is composed of nanolayers of Ti.sub.0.80Si.sub.0.20N, Ti.sub.0.40Al.sub.0.60N and Ti.sub.0.25Al.sub.0.75N, [0074] Sample 4 for the coated cutting tools where the nano-multilayer is composed of nanolayers of Ti.sub.0.80Si.sub.0.20N, Ti.sub.0.40Al.sub.0.60N and Ti.sub.0.15Al.sub.0.85N, [0075] Sample 5 for the coated cutting tools where the nano-multilayer is composed of nanolayers of Ti.sub.0.80Si.sub.0.20N, Ti.sub.0.40Al.sub.0.60N and Ti.sub.0.05Al.sub.0.95N.

Example 4

[0076] Coated cutting tools were provided comprising a nano-multilayer of Ti.sub.0.80Si.sub.0.20N, Ti.sub.0.40Al.sub.0.60N and Ti.sub.0.25Al.sub.0.75N nanolayers deposited on sintered cemented carbide cutting tool insert blanks of the geometries CNMG120408MM and R390-11T308M-PM. The composition of the cemented carbide was 10 wt % Co, 0.4 wt % Cr and rest WC. The cemented carbide blanks were coated by cathodic arc evaporation in a vacuum chamber comprising four arc flanges, each flange comprising several cathode evaporators. Targets of Ti.sub.0.80Si.sub.0.20 were mounted in the evaporators in two of the flanges opposite each other. The remaining targets Ti.sub.0.40Al.sub.0.60 and Ti.sub.0.25Al.sub.0.75 were mounted in the evaporators in the two remaining flanges opposite each other. The targets were circular and planar with a diameter of 100 mm available on the open market. Suitable target technology packages for arc evaporation are available from suppliers on the market such as IHI Hauzer Techno Coating B.V., Kobelco (Kobe Steel Ltd.) and Oerlikon Balzers.

[0077] The uncoated blanks were mounted on pins that undergo a three-fold rotation in the PVD chamber.

[0078] The chamber was pumped down to high vacuum (less than 10.sup.-2 Pa) and heated to about 450-550? C. by heaters located inside the chamber. The blanks were then etched for 60 minutes in an Ar plasma.

[0079] At first, an innermost layer being a nano-multilayer of Ti.sub.0.40Al.sub.0.60N and Ti.sub.0.25Al.sub.0.75N nanolayers was deposited by only using the Ti.sub.0.40Al.sub.0.60 and Ti.sub.0.25Al.sub.0.75 targets.

[0080] The chamber pressure (reaction pressure) was set to 4 Pa of N.sub.2 gas, and a DC bias voltage of ?100 V (relative to the chamber walls) was applied to the blank assembly. The cathodes were run in an arc discharge mode at a current of 150 A (each) for 50 minutes (2 flanges). The table rotational speed was 5 rpm. A layer of a nano-multilayer of Ti.sub.0.40Al.sub.0.60N and Ti.sub.0.25Al.sub.0.75N having a thickness of about 1 ?m was deposited on the blanks. Since the rotational speed for the current deposition rate and equipment used correlates to a certain period thickness it was concluded that the average individual nanolayer thickness was about 2 nm.

[0081] Then, the nano-multilayer of Ti.sub.0.80Si.sub.0.20N, Ti.sub.0.40Al.sub.0.60N and Ti.sub.0.25Al.sub.0.75N nanolayers was deposited by using all mounted targets.

[0082] The chamber pressure (reaction pressure) was set to 4 Pa of N.sub.2 gas, and a DC bias voltage of ?100 V (relative to the chamber walls) was applied to the blank assembly. The cathodes were run in an arc discharge mode at a current of 150 A (each) for 50 minutes (4 flanges). The table rotational speed was 5 rpm. A nano-multilayer coating having a thickness of about 2 ?m was deposited on the blanks.

[0083] The rotational speed correlates to a certain period thickness and it was concluded that a table rotational speed of 5 rpm for the current deposition rate and equipment used correlates to an average individual nanolayer thickness of each of the nanolayers Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.80Si.sub.0.20N and Ti.sub.0.25Al.sub.0.75N of about 2 nm. The number of nanolayers in the nano-multilayer is about 1000.

[0084] The nano-multilayer comprises a repeating sequence of consecutive nanolayers in the order Ti.sub.0.40Al.sub.0.60N/Ti.sub.0.80Si.sub.0.20N/Ti.sub.0.25Al.sub.0.75N/Ti.sub.0.80Si.sub.0.20N.

[0085] Finally, an outermost layer of Ti.sub.0.25Al.sub.0.75N, in order to obtain an even colour between the individual coated cutting tools made, was deposited by only using the Ti.sub.0.25Al.sub.0.75 target. All deposition parameters were the same as for depositing the previous layer, and the cathodes were run for 10 minutes (1 flange). A layer of Ti.sub.0.25Al.sub.0.75N was deposited to a thickness of about 0.2 ?m.

[0086] In the nano-multilayer of three nanolayer types, the thickness ratio sum of thicknesses of each of the nanolayers Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.80Si.sub.0.20N, Ti.sub.0.25Al.sub.0.75N, respectively, i.e., Ti.sub.0.40Al.sub.0.60N: Ti.sub.0.80Si.sub.0.20N: Ti.sub.0.25Al.sub.0.75N, is about 1:2:1. The ratio is estimated from a deposition rate from each target assumed to be the same, the rotation during deposition and the deposition time.

[0087] The coated cutting tools were called Sample 6.

Example 5

[0088] Coated cutting tools were provided comprising a nano-multilayer of Ti.sub.0.80Si.sub.0.20N, Ti.sub.0.40Al.sub.0.60N and Ti.sub.0.15Al.sub.0.85N nanolayers deposited on sintered cemented carbide cutting tool insert blanks of the geometries CNMG120408MM and R390-11T308M-PM. The composition of the cemented carbide was 10 wt % Co, 0.4 wt % Cr and rest WC. The cemented carbide blanks were coated by cathodic arc evaporation in a vacuum chamber comprising four arc flanges, each flange comprising several cathode evaporators. Two targets of Ti.sub.0.15Al.sub.0.85 were mounted in the evaporators in two of the flanges opposite each other. The remaining targets Ti.sub.0.40Al.sub.0.60 and Ti.sub.0.80Si.sub.0.20 were mounted in the evaporators in the two remaining flanges opposite each other. The targets were circular and planar with a diameter of 100 mm available on the open market. Suitable target technology packages for arc evaporation are available from suppliers on the market such as IHI Hauzer Techno Coating B.V., Kobelco (Kobe Steel Ltd.) and Oerlikon Balzers.

[0089] The uncoated blanks were mounted on pins that undergo a three-fold rotation in the PVD chamber.

[0090] The chamber was pumped down to high vacuum (less than 10.sup.-2 Pa) and heated to about 450-550? C. by heaters located inside the chamber. The blanks were then etched for 60 minutes in an Ar plasma.

[0091] At first, an innermost layer of Ti.sub.0.40Al.sub.0.60N was deposited by only using the Ti.sub.0.40Al.sub.0.60 target.

[0092] The chamber pressure (reaction pressure) was set to 4 Pa of N.sub.2 gas, and a DC bias voltage of ?70 V (relative to the chamber walls) was applied to the blank assembly. The cathodes were run in an arc discharge mode at a current of 150 A (each) for 100 minutes (1 flange). The table rotational speed was 5 rpm. A layer of Ti.sub.0.40Al.sub.0.60N having a thickness of about 1 ?m was deposited on the blanks.

[0093] Then, the nano-multilayer was deposited by using all mounted targets.

[0094] The chamber pressure (reaction pressure) was set to 4 Pa of N.sub.2 gas, and a DC bias voltage of ?100 V (relative to the chamber walls) was applied to the blank assembly. The cathodes were run in an arc discharge mode at a current of 150 A (each) for 50 minutes (4 flanges). The table rotational speed was 5 rpm. A nano-multilayer coating having a thickness of about 2 ?m was deposited on the blanks.

[0095] The rotational speed correlates to a certain period thickness and it was concluded that a table rotational speed of 5 rpm for the current deposition rate and equipment used correlates to an average individual nanolayer thickness of each of the nanolayers Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.80Si.sub.0.20N and Ti.sub.0.15Al.sub.0.85N of about 2 nm. The number of nanolayers in the nano-multilayer is about 1000.

[0096] The nano-multilayer comprises a repeating sequence of consecutive nanolayers in the order Ti.sub.0.15Al.sub.0.85N/Ti.sub.0.40Al.sub.0.60N/Ti.sub.0.15Al.sub.0.85N/Ti.sub.0.80Si.sub.0.20N.

[0097] Finally, an outermost layer of Ti.sub.0.15Al.sub.0.85N, in order to obtain an even colour between the individual coated cutting tools made, was deposited by only using the Ti.sub.0.15Al.sub.0.85 target. All deposition parameters were the same as for depositing the previous layer and the cathodes were run for 10 minutes (1 flange). A layer of Ti.sub.0.15Al.sub.0.85N was deposited to a thickness of about 0.2 ?m.

[0098] The coated cutting tools were called Sample 7.

[0099] In the nano-multilayer, the thickness ratio sum of thicknesses of each of the nanolayers Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.80Si.sub.0.20N, Ti.sub.0.15Al.sub.0.85N, respectively, i.e., Ti.sub.0.40Al.sub.0.60N: Ti.sub.0.80Si.sub.0.20N: Ti.sub.0.15Al.sub.0.85N, is about 1:1:2. The ratio is estimated from a deposition rate from each target assumed to be the same, the rotation during deposition and the deposition time.

[0100] The samples 1-7 made are listed in Table 1.

TABLE-US-00001 TABLE 1 Nano-multilayer First Second Third nanolayer nanolayer nanolayer Outermost Sample Inner layer type type type layer 1 Ti.sub.0.50Al.sub.0.50N, Ti.sub.0.50Al.sub.0.50N Ti.sub.0.85Si.sub.0.15N Ti.sub.0.20Al.sub.0.80N Ti.sub.0.85Si.sub.0.15N invention 1.4 ?m 1.4 ?m 0.2 ?m 2 Ti.sub.0.50Al.sub.0.50N, Ti.sub.0.50Al.sub.0.50N* Ti.sub.0.85Si.sub.0.15N** Ti.sub.0.20Al.sub.0.80N** Ti.sub.0.85Si.sub.0.15N comparative 1.4 ?m 1.4 ?m 0.2 ?m 3 Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.40Al.sub.0.60N Ti.sub.0.80Si.sub.0.20N Ti.sub.0.25Al.sub.0.75N Ti.sub.0.25Al.sub.0.75N invention 1 ?m 2 ?m 0.2 ?m 4 Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.40Al.sub.0.60N Ti.sub.0.80Si.sub.0.20N Ti.sub.0.15Al.sub.0.85N Ti.sub.0.15Al.sub.0.85N invention 1 ?m 2 ?m 0.2 ?m 5 Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.40Al.sub.0.60N Ti.sub.0.80Si.sub.0.20N Ti.sub.0.05Al.sub.0.95N Ti.sub.0.05Al.sub.0.95N comparative 1 ?m 2 ?m 0.2 ?m 6 nano-multi Ti.sub.0.40Al.sub.0.60N Ti.sub.0.80Si.sub.0.20N Ti.sub.0.25Al.sub.0.75N Ti.sub.0.25Al.sub.0.75N invention Ti.sub.0.40Al.sub.0.60N/ 2 ?m 0.2 ?m Ti.sub.0.25Al.sub.0.75N 1 ?m 7 Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.40Al.sub.0.60N Ti.sub.0.80Si.sub.0.20N Ti.sub.0.15Al.sub.0.85N Ti.sub.0.15Al.sub.0.85N invention 1 ?m 2 ?m 0.2 ?m *about 35 nm Ti.sub.0.50Al.sub.0.50N **about 35 nm nano-multilayer of Ti.sub.0.85Si.sub.0.15N/Ti.sub.0.20Al.sub.0.80N

[0101] Table 2 further summarises the samples 1-7.

TABLE-US-00002 TABLE 2 Thickness ratio sum of nanolayer Nanolayer sequence in nano- thicknesses of each nanolayer type Sample Inner layer multilayer Ti.sub.1?xAl.sub.xN:Ti.sub.1?ySi.sub.yN:Ti.sub.1?zAl.sub.zN 1 Ti.sub.0.50Al.sub.0.50N, (Ti.sub.0.50Al.sub.0.50N/Ti.sub.0.20Al.sub.0.80N/ 2:1:1 invention 1.4 ?m Ti.sub.0.50Al.sub.0.50N/Ti.sub.0.85Si.sub.0.15N).sub.175 2 Ti.sub.0.50Al.sub.0.50N, (35 nm Ti.sub.0.50Al.sub.0.50N + 35 nm 2:1:1 comparative 1.4 ?m (Ti.sub.0.85Si.sub.0.15N/Ti.sub.0.20Al.sub.0.80N).sub.9).sub.20 3 Ti.sub.0.40Al.sub.0.60N, (Ti.sub.0.40Al.sub.0.60N/Ti.sub.0.80Si.sub.0.20N/ 1:2:1 invention 1 ?m Ti.sub.0.25Al.sub.0.75N/Ti.sub.0.80Si.sub.0.20N).sub.250 4 Ti.sub.0.40Al.sub.0.60N, (Ti.sub.0.40Al.sub.0.60N/Ti.sub.0.80Si.sub.0.20N/ 1:2:1 invention 1 ?m Ti.sub.0.15Al.sub.0.85N/Ti.sub.0.80Si.sub.0.20N).sub.250 5 Ti.sub.0.40Al.sub.0.60N, (Ti.sub.0.40Al.sub.0.60N/Ti.sub.0.80Si.sub.0.20N/ 1:2:1 comparative 1 ?m Ti.sub.0.05Al.sub.0.95N/Ti.sub.0.80Si.sub.0.20N).sub.250 6 nano-multi (Ti.sub.0.40Al.sub.0.60N/Ti.sub.0.80Si.sub.0.20N/ 1:2:1 invention Ti.sub.0.40Al.sub.0.60N/ Ti.sub.0.25Al.sub.0.75N/Ti.sub.0.80Si.sub.0.20N).sub.250 Ti.sub.0.25Al.sub.0.75N 1 ?m 7 Ti.sub.0.40Al.sub.0.60N, (Ti.sub.0.15Al.sub.0.85N/Ti.sub.0.40Al.sub.0.60N/ 1:1:2 invention 1 ?m Ti.sub.0.15Al.sub.0.85N/Ti.sub.0.80Si.sub.0.20N).sub.250

Example 6

[0102] Cutting tests were made in order to determine the performance of the samples made.

Explanations to Terms Used:

The following expressions/terms are commonly used in metal cutting, but nevertheless explained in the table below: [0103] Vc (m/min): cutting speed in meters per minute [0104] fz (mm/tooth): feed rate in millimeter per tooth (in milling) [0105] fn (mm/rev) feed rate per revolution (in turning) [0106] z: (number) number of teeth in the cutter [0107] a.sub.e (mm): radial depth of cut in millimeter [0108] a.sub.p (mm): axial depth of cut in millimeter

Flank Wear Test:

[0109] Longitudinal turning [0110] Work piece material: Sverker 21 (tool steel), Hardness?210 HB, D=180, L=700 mm, V.sub.c=125 m/min [0111] f.sub.n=0.072 mm/rev [0112] a.sub.p=2 mm [0113] without cutting fluid

[0114] The cut-off criteria for tool life is a flank wear VB of 0.15 mm.

Flaking Resistance:

[0115] The evaluation was made through turning test in austenitic stainless steel. In order to provoke adhesive wear and flaking of the coating the depth of cut a.sub.p was varied between 4 to 0 and 0 to 4 mm (in one run during radial facing). The inserts were evaluated through SEM analysis. [0116] Operation: Facing (turning) [0117] Work piece material: Bar of austenitic stainless steel Sanmac 316L, L=200 mm, D=100 mm, ?215 HB [0118] Insert type: CNMG 120408MM [0119] Cooling: yes [0120] Depth of cut a.sub.p=4 to 0, 0 to 4 mm [0121] Cutting speed V.sub.c=140 m/min [0122] Feed rate f.sub.z=0.36 mm/rev

TABLE-US-00003 TABLE 3 Flank wear Flaking resistance resistance 140 m/min Sample (Tool life, min) (Flaked area mm.sup.2) 1 13 0.04 invention 2 7 0.26 comparative 3 18 0.12 invention 4 12 0.14 invention 5 6 0.15 comparative 6 14 0.16 invention 7 13 0.17 invention

[0123] It is concluded that samples 1, 3, 4, 6 and 7, within the invention, have high flank wear resistance and show much less flank wear than comparative samples 2 and 5 outside the invention.

[0124] It is concluded that samples 1, 3, 4, 6 and 7, within the invention, have high flaking resistance and perform much better that comparative sample 2 outside the invention.

Effect of Alternative Inner Layer:

[0125] Sample 3 and sample 6 differ in that sample 6 has an inner (Ti,Al)N nano-multilayer instead of a single (Ti,Al)N layer. Further cutting tests were made on Sample 3 and Sample 6 in order to determine the effect on comb crack resistance and edge line toughness by having the alternative inner layer in Sample 6.

Comb Crack Resistance:

[0126] Operation: Shoulder milling [0127] Tool holder: C5-391.20-25 080 [0128] Work piece material: Toolox 33 (tool steel), L=600 mm, I=200 mm, h=100 mm, [0129] Insert type: R390-11T308M-PM [0130] Cutting speed V.sub.c=250 m/min [0131] Feed rate f.sub.z=0.2 mm/rev [0132] Depth of cut a.sub.p=3 mm [0133] Radial engagement a.sub.e=12.5 mm [0134] with cutting fluid

[0135] The criteria for end of tool life is a max. chipped height VB>0.3 mm.

Edge Line Toughness:

[0136] Work piece material: Dievar unhardened, P3. 0.Z.AN, [0137] z=1 [0138] V.sub.c=200 m/min [0139] f.sub.z=0.20 mm [0140] a.sub.e=12 mm [0141] a.sub.p=3.0 [0142] length of cut=12 mm [0143] without cutting fluid

[0144] The cut-off criteria are chipping of at least 0.5 mm of the edge line or a measured depth of 0.2 mm at either the flank-or the rake phase. Tool life is presented as the number of cut entrances in order to achieve these criteria.

TABLE-US-00004 TABLE 5 Comb crack Edge line Nanolayers in resistance toughness Sample Inner layer nano-multilayer (No. cuts) (No. cuts) 3 Ti.sub.0.40Al.sub.0.60N, Ti.sub.0.40Al.sub.0.60N/ 29 24 invention Ti.sub.0.80Si.sub.0.20N/ Ti.sub.0.25Al.sub.0.75N 6 nano-multi Ti.sub.0.40Al.sub.0.60N/ 37 50 invention Ti.sub.0.40Al.sub.0.60N/ Ti.sub.0.80Si.sub.0.20N/ Ti.sub.0.25Al.sub.0.75N Ti.sub.0.25Al.sub.0.75N

[0145] The results in both the comb crack resistance test and edge line toughness (ELT) test are improved by the presence of an inner nano-multi Ti.sub.0.40Al.sub.0.60N/Ti.sub.0.25Al.sub.0.75N layer instead of an inner Ti.sub.0.40Al.sub.0.60N layer.