METHOD AND DEVICE FOR APPLYING A COATING, AND COATED BODY

Abstract

The invention relates to a method and a device to for applying a layer 64 to a body 60, 62, and to a coated body 60. The body 60, 62 is disposed in a vacuum chamber 12 and process gas is supplied. A plasma is generated in the vacuum chamber 12 by operating a cathode 30 by applying a cathode voltage V.sub.P with cathode pulses and by sputtering a target 32. A bias voltage V.sub.B is applied to the body 60, 62 so that charge carriers of the plasma are accelerated into the direction of the body 60, 62 and attached to its surface. In order to achieve favorable properties of the coating 64 in a controlled way, the time course of the bias voltage V.sub.B is varied during the coating duration D. In the coating 64 of the body 60, 62, the material of the layer 64 comprises proportions of a noble gas, the concentration of which in the layer 64 varies over the layer thickness.

Claims

1. A method for applying a layer to a body, comprising disposing the body in a vacuum chamber, supplying a process gas into the vacuum chamber, generating a plasma in the vacuum chamber by operating at least one cathode by applying a cathode voltage with cathode pulses and sputtering a target, applying a bias voltage to the body so that charge carriers of the plasma are accelerated into the direction of the body and attached to its surface during a coating duration, wherein a time course of the bias voltage comprises bias pulses during at least a part of the coating duration, wherein the bias pulses are synchronized with the cathode pulses, and wherein the time course of the bias voltage varies during the coating duration by a change of the duration and/or the synchronization of the bias pulses with respect to the cathode pulses.

2. (canceled)

3. The method according to claim 1, wherein a proportion of the process gas in the layer is dependent on the time course of the bias voltage, and wherein, by variation of the time course of the bias voltage during the coating duration, a proportion of process gas in the layer varies.

4. The method according to claim 1, wherein the time course of the bias voltage comprises bias pulses at least during a first time interval, and wherein the bias voltage is a DC voltage at least during another time interval.

5. The method according to one claim 1, wherein the time course of the bias voltage comprises bias pulses at least during a first time interval, wherein the bias pulses are synchronized with the cathode pulses, and wherein the bias pulses occur delayed with respect to the cathode pulses by a delay time.

6. The method according to claim 5, wherein during the first time interval, the bias pulses occur delayed with respect to the cathode pulses by a first delay time, and the time course of the bias voltage comprises, at least during a second time interval, bias pulses which are synchronized with the cathode pulses and occur delayed with respect to the cathode pulses by a second delay time, wherein the first and the second delay times differ.

7. The method according to claim 6, wherein the duration of the first time interval and/or the second time interval is chosen so that, during it, the layer grows by 0.1 μm-3 μm.

8. The method according to claim 6, wherein the first time interval is before the second time interval within the coating duration, and the delay time in the first time interval is shorter than in the second time interval.

9. The method according to claim 8, wherein the first time interval is at the beginning of the coating duration.

10. The method according to claim 5, wherein the delay time changes during a transition time interval in steps or continuously from a first value to a second value.

11. The method according to claim 10, wherein the duration of the transition time interval is chosen so that, during it, the layer grows by 0.5 μm-20 μm.

12. The method according to claim 5, wherein during a first switching subinterval the delay time has a first value and during a second switching subinterval the delay time has a second value and during a switching time interval, alternating first and second switching subintervals follow each other.

13. The method according to claim 12, wherein the duration of the first and/or of the second switching subinterval is each chosen so that, during this time, the layer grows by 5-500 nm.

14. The method according to claim 1, wherein the cathode is operated by applying the cathode pulses according to the HIPIMS method and the process gas is argon.

15. A device for applying a layer to a body, with a vacuum chamber with a carrier for the body, a process gas supply, and at least one cathode with a target, a pulsed cathode power supply for supplying the cathode with an electrical cathode voltage with cathode pulses during a coating duration, a controllable bias power supply for applying a bias voltage to the body and a controller for controlling the bias power supply so that a time course of the bias voltage comprises bias pulses during at least a part of the coating duration, the bias pulses being synchronized with the cathode pulses, and wherein the time course of the bias voltage varies during the coating duration by a change of the duration and/or the synchronization of the bias pulses with respect to the cathode pulses.

16. (canceled)

Description

[0042] FIG. 1 a schematic representation of a coating system with electrical circuitry;

[0043] FIG. 2 a diagram with a time progression of a cathode pulse and a bias pulse;

[0044] FIG. 3 a diagram with a representation of the amount and type of ions in the plasma in a temporal sequence starting with the triggering of a cathode pulse;

[0045] FIG. 4a-4d diagrams of the temporal superposition of various time courses of the bias voltage with number and type of ions in the plasma in accordance with FIG. 3;

[0046] FIG. 5 an exemplary embodiment of a coating in a schematic representation of a surface region of a coated body;

[0047] FIG. 6a, 6b a first exemplary embodiment of a coating as a time progression diagram and in a schematic representation of a surface region of a coated body;

[0048] FIG. 7a, 7b a second exemplary embodiment of a coating as a time progression diagram and in a schematic representation of a surface region of a coated body;

[0049] FIG. 8a, 8b a third exemplary embodiment of a coating as a time progression diagram and in a schematic representation of a surface region of a coated body;

[0050] FIG. 9a, 9b a fourth exemplary embodiment of a coating as a time progression diagram and in a schematic representation of a surface region of a coated body;

[0051] FIG. 10a, 10b a fifth exemplary embodiment of a coating as a time progression diagram and in a schematic representation of a surface region of a coated body;

[0052] FIG. 11a, 11b a sixth exemplary embodiment of a coating as a time progression diagram a schematic representation of a surface region of a coated body;

[0053] FIG. 12 an exemplary embodiment of a tool with a coating.

[0054] FIG. 1 shows a schematic representation of a coating system 10. The coating system 10 comprises a vacuum chamber 12, shown here schematically from above, with a vacuum system 14, by means of which a vacuum can be generated inside the vacuum chamber 12. The vacuum chamber 12 also has a process gas supply 16 and a reactive gas supply 18, by means of which process gas, in the preferred embodiment argon, and reactive gas, for example nitrogen, can be introduced into the vacuum chamber 12.

[0055] A rotating substrate table 20 with planetarily rotating substrate carriers 22 is located within the vacuum chamber 12. Substrates 60 to be coated, i.e., base bodies, for example of tools (see FIG. 12) are respectively disposed on the substrate carriers 22 and are electrically contacted with the substrate carriers 22 and the substrate table 20.

[0056] Magnetron cathodes 30, 34 and an anode 28 are also disposed within the vacuum chamber 10. Each of the magnetron cathodes 32, 34 comprises an unbalanced magnet system (not shown) and a plate-shaped sputtering target 32, 36.

[0057] The magnetron cathodes 30, 34, the substrate table 20, and the anode 28 are each connected from outside the vacuum chamber 12 to an outer electrical circuitry of the coating system 10 by means of an electrical feedthrough through the wall of the vacuum chamber 12.

[0058] In the example shown, the magnetron cathode 34 is wired as a DC cathode, i.e., connected to a DC power supply 44 which supplies a DC voltage to it with respect to the anode 28. The anode 28 is connected to an anode power supply 46 which supplies a DC voltage to it with respect to the conductive wall of the vacuum chamber 12. The magnetron cathode 30 is wired as an HIPIMS cathode, i.e., electrically connected to an HIPIMS power supply 40 which applies a pulsed voltage V.sub.P to it with respect to the chamber wall. The substrate table 20 is connected to a bias power supply 42 which supplies it with a bias voltage V.sub.B with respect to the anode 28.

[0059] The coating system 10 is equipped with a controller 48, by which the bias power supply 42 and the HIPIMS power supply 40 are controlled, as will be explained in detail below. In addition, the controller 48 controls the entire process, i.e., also the vacuum system, the rotary drive of the substrate table 20, the supply of process gas and reactive gas, and all other electrical power supplies 44, 46. The controller is programmable, i.e., it comprises a memory for coating programs, with which the procedures and method steps explained below are specified.

[0060] It should be noted that the electrical circuitry and the fitting of the coating system 10 with electrodes as shown is to be understood to be purely exemplary. In alternative embodiments, for example, the HIPIMS cathode 30 can be connected with respect to the anode 28, or, for example, the anode 28 can be dispensed with and the chamber wall can be wired as the anode for all cathodes and for the substrate table 20. Multiple or also no DC cathodes 34 can be provided. In addition to the HIPIMS cathode 30, additional HIPIMS cathodes can be provided in the vacuum chamber 12, each connected to its own HIPIMS power supply. The cathodes 30, 34 can be fitted with targets 32, 36 of the same or different compositions.

[0061] The HIPIMS power supply 40 supplies electrical power to the HIPIMS cathode 30 in accordance with the HIPIMS method, i.e., the supplied voltage V.sub.P, the current I.sub.P, and thus the instantaneous electrical power have a time course in the form of short, very high pulses.

[0062] As an example, a period duration T of such a periodic time course is shown in FIG. 2. The voltage V.sub.P applied to the HIPIMS cathode 30 is negative. The time course comprises approximately rectangular voltage pulses 50 of a pulse duration T.sub.P. For the rest of the period duration T, no voltage is applied.

[0063] By way of example, preferred parameters of the HIPIMS method are mentioned below. The voltage V.sub.P is applied periodically with a frequency of, for example, 100-10,000 Hz, preferably 500-4000 Hz, so that the period duration T is preferably in the range of 250-2000 μs. The pulse duration T.sub.P is preferably low, for example shorter than 200 μs, preferably 40-100 μs. Preferably, the duty cycle T.sub.P/T is in the range of 1% to 35%, preferably 10-30%, particularly preferably 20-28%. The operation of the HIPIMS cathode(s) 30 preferably takes place in a power-regulated manner, for example to a value of 3-20 kW per HIPIMS cathode, preferably 10-16 kW per cathode. The peak current resulting during a pulse, in relation to the front face of the target 32, is preferably 0.4-2 A/cm.sup.2, further preferably 0.5-0.8 A/cm.sup.2.

[0064] When the coating system 10 is operated for applying a coating 64 to the functional region 62 of a substrate 60, as shown by way of example in FIG. 12 for a milling cutter 66, the substrates 60 to be coated are disposed on the substrate carriers 22 within the vacuum chamber 12. A vacuum is generated inside the vacuum chamber 12. After optional preparation steps (for example, heating, surface treatment of the substrates 60 by means of ion etching, sputter cleaning of the cathodes 30, 34, etc.), a plasma is generated by operating one or more HIPIMS cathodes 30 (and, optionally, one or more DC cathodes 34 at the same time) while sputtering the target 32, 36. Components of the plasma attach themselves to the surface of the substrates 60 and form the layer 64, wherein positively charged ions of the plasma are accelerated into the direction toward the substrate surface by the negative bias voltage V.sub.B.

[0065] FIG. 3 shows, by way of example, the ions measured in the plasma in temporal resolu-tion after the start of a cathode pulse 50 at t=0 μs for an HIPIMS cathode 30 with a target 32 made of titanium and aluminum and while supplying argon as the process gas. As shown, the plasma contains various species of metal and gas ions, wherein, however, the different species show time courses that deviate from each other. Thus, the number of argon ions increases relatively quickly up to a local maximum of approx. 35 μs, then decreases and increases again considerably in the later course starting at approx. t=90 μs. The metal ions increase somewhat more slowly, reach a maximum approximately in the range of t=50-60 μs and then decrease again.

[0066] As schematically shown, three time sections 54, 56, 58 can be defined, wherein in the first time section 54 (approx. 0-40 μs) gas ions prevail, in the following second time section 56 (from approx. 40-100 μs) the metal ions prevail, and in the following third time section 58 (from approx. 100 μs) the gas ions prevail considerably.

[0067] The positive gas and metal ions of the plasma are accelerated into the direction toward the surface of the substrate 60 by the negative bias voltage V.sub.B and thus become part of the coating 64 attaching itself there. In the case of a DC bias, i.e., a continuous DC voltage as the bias voltage V.sub.B, all ions are selected for the layer formation without exception. In FIG. 4d, this is shown by way of example in that all three time sections 54, 56, 58 during which the bias voltage V.sub.B is constantly applied are shown crosshatched.

[0068] Alternatively to a DC bias, the bias voltage V.sub.B can be applied with a pulsed time course, synchronously to the time course of the voltage V.sub.P at the HIPIMS cathode 30. Such a pulsed time course of the bias voltage V.sub.B is shown by way of example in FIG. 2. The bias voltage V.sub.B has a rectangular pulse 52 (bias pulse) which is applied during a bias pulse duration T.sub.B during the cathode pulse 50. In this case, the bias pulse 52 is temporally delayed with respect to the cathode pulse by a delay time T.sub.D.

[0069] By suitable selection of the temporal synchronization between the cathode pulses 50 and the bias pulses 52, i.e., in particular by suitable selection of the bias pulse duration T.sub.B and the delay time T.sub.D, a selection can be made among the gas and metal ions present in the plasma at various points in time.

[0070] For example, the effect of a presetting of a time course of the bias pulses 52 with a bias pulse duration T.sub.B of approx. 60 s and a delay time T.sub.D of approx. 40 μs is shown in FIG. 4a. The bias pulse 52 is thus synchronized with the second time section 56, in which metal ions prevail. By presetting such a time course of the bias voltage V.sub.B, a coating 64 with a very low proportion of argon is generated.

[0071] In experiments with an HIPIMS target 32 made of titanium, silicon, and aluminum and supplying nitrogen as the reactive gas for depositing a coating 64 made of a Ti—Al—Si—N material system, with the time course of the bias voltage V.sub.B illustrated in FIG. 4a a proportion of argon of 0.03 at % in the coating 64 resulted. The coating 64 had an internal stress of −1.6 GPa and a hardness of 26 GPa.

[0072] In comparison to this, with an otherwise identical configuration and process control with the application of a DC bias (FIG. 4d), a proportion of argon in the coating 64 of 0.12 at %, an internal stress of −5.3 GPa, and a hardness of 30 GPa was shown.

[0073] As a further example of a possible time course of the bias voltage V.sub.B, FIG. 4b shows a time course with a bias pulse duration T.sub.B of approx. 60 μs and a delay time T.sub.D of approx. 100 μs, so that the bias pulse 52 is synchronized with the third time section 58, in which gas ions prevail. By presetting this time course of the bias voltage V.sub.B, a coating 64 with a high proportion of argon is therefore generated.

[0074] As another example, FIG. 4c shows the effect of a time course of the bias voltage V.sub.B with a bias pulse duration T.sub.B of approx. 100 μs and a delay time T.sub.D of approx. 20 μs. The bias pulse 52 covers the second time section 56 completely and the first and third time sections 54, 58 partially in each case. By presetting this time course of the bias voltage V.sub.B a coating 64 with a moderate proportion of argon is generated.

[0075] Thus, by presetting the time course of the bias voltage V.sub.B, it is possible to influence the layer composition and in particular to set the proportion of argon in a controlled way to a value between a minimum proportion (FIG. 4a) and a maximum proportion (FIG. 4b).

[0076] As a result, the layer properties are considerably influenced, in particular the internal stress in the coating 64 and its hardness.

[0077] By means of the coating system 10, coatings 64 are applied to each of the substrates 60. These coatings grow with the progressing coating duration D so that they each have a thickness S starting from the surface of the substrate 60. By means of the controller 48, both the HIPIMS power supply 40 and the bias power supply 42 are controlled during the coating duration D so that, in various time intervals during the coating duration D, time courses of the bias voltage V.sub.B that deviate from each other can be set. This results in a varying composition of the coating 64 over the layer thickness S, namely a different respective proportion of argon depending on the time course set in each case.

[0078] With bias pulses 52 synchronized with the cathode pulses 50 (FIG. 2), the time course can be characterized by the delay time T.sub.D and the bias pulse duration T.sub.B. By way of example, the bias pulse duration T.sub.B can be set from this to a fixed value of, for example, 60 μs, while the delay time T.sub.D varies depending on the coating duration D.

[0079] An exemplary embodiment is explained below with reference to FIG. 5, in which a two-layer coating 64 is deposited on a substrate 62 by a one-time change of the synchronization of the bias voltage V.sub.B during the coating duration.

[0080] To apply the coating 66, initially the body 60 to be coated, made of substrate material 62, is positioned on the substrate carrier 22 within the vacuum chamber 12, for example a double-bladed ball end mill with a 6 mm diameter made of carbide (WC/Co) with a 6 at % cobalt content.

[0081] The coating system 10 is fitted with two four HIPIMS cathodes 30, which are disposed around the substrate table 20. Each two cathodes 30 disposed next to each other are fitted with targets 32 made of titanium aluminum material (for example, 60 at % Ti, 40 at % Al) and the two remaining are fitted with targets 32 made of titanium silicon material (for example, 80 at % Ti, 20 at % Si).

[0082] By operating the vacuum system 14, a vacuum is produced. The inside of the vacuum chamber 12 is heated up. The surface of the substrate 60 is cleaned by gas ion etching while the cathodes 30, 34 are operated. The targets 32, 36 are prepared by sputter cleaning.

[0083] At the beginning of the coating, initially a first layer Boa is deposited on the substrate 60 in a first time interval. For this purpose, the two cathodes 30 with Al—Ti targets are operated, each with 12 kW of cathode power, while the two remaining cathodes 30 with Ti—Si targets are initially not operated. The electrical power is supplied in the form of HIPIMS cathode pulses 50 with a frequency of 4000 Hz, pulse length 70 μs. A bias voltage V.sub.B is applied thereby to the substrate 60 via the substrate table 20 and the substrate carrier 22. The bias voltage V.sub.B is pulsed with bias pulses 52 of 60 V and a bias pulse duration T.sub.B of 40 μs, which are synchronous with the cathode pulses 60 but occur with a delay time T.sub.D of 40 μs.

[0084] The first layer Boa is deposited with a layer rate of approximately 1 μm/h so that it reaches a thickness of 1.5 μm after the duration of the first time interval of 1.5 h. Due to the pulsed bias voltage V.sub.B with a delay time T.sub.D of 40 μs, metal ions are selected in a controlled way to form the coating 64, while argon ions, which first increasingly occur in the later temporal curve of each pulse, are only present to a low degree (cf. FIG. 4a). The argon content of the coating 64 in the first layer Boa is less than or equal to 0.03 at %, so that internal stress of less than or equal to −1.6 GPa results.

[0085] Subsequently, in a second time interval, a second layer Bob is deposited onto the 1.5 μm thick first layer 80a. For this purpose, in the further execution of the coating program, the controller 48 controlls the power supplies of the two cathodes 30 with Ti—Si targets such that they are each operated with 12 kW of cathode power, while the two remaining cathodes 30 with Al—Ti targets are not operated. The HIPIMS parameters of the electrical power supply in the second time interval are the same as in the first time interval, i.e., frequency of 4000 Hz, pulse length 70 μs.

[0086] However, in the transition from the first to the second time interval, a variation of the time course of the bias voltage V.sub.B is made such that it is not applied in the second time interval with a pulsed time course, but rather as a continuous DC voltage, so that argon ions are also contained in the coating 64 to a considerable extent.

[0087] The second layer Bob is deposited with a layer rate of approximately 1 μm/h so that it reaches a thickness of 1.5 μm after the duration of the second time interval of 1.5 h. Due to the non-pulsed bias voltage V.sub.B, the argon content of the coating 64 in the second layer Bob is at least 0.12 at %, such that internal stress of at least 5.3 GPa results.

[0088] As a result, the layer 64 is two-layered, wherein the first layer Boa achieves very good layer adhesion due to the low internal stress and higher ductility, while the outer, second layer Bob ensures a hard, smooth surface of the coated body 66. The ball end mill coated in this way is suitable for milling high-carbon steel of more than 60 HRC without emulsion.

[0089] In the following, further individual exemplary embodiments in which coatings 164, 264, 364, 464, 564, 664 are generated on the substrate 62 are shown, wherein the composition and the properties of the coatings are changed in each case by variation of the time course during the coating duration, in particular by changing the synchronization of the bias voltage V.sub.B. In the following representation, all further details of the coating procedure will not be mentioned, for example fitting the targets and the concrete parameters and time durations, since it is primarily about showing principal embodiments, which can be applied to various material systems and with various parameters.

[0090] FIG. 6a, 6b show a first exemplary embodiment of a coated body 166 with a two-layer coating 164.

[0091] When depositing the coating 164, the bias voltage V.sub.B is applied in each case with a pulsed time course with bias pulses 52 which are synchronized with the cathode pulses 50. However, as shown in FIG. 6a, the synchronization is changed during the coating duration D. Thus, in a first time interval 170a, the delay time T.sub.D is initially 40 μs and in a following second time interval 170b is 110 μs.

[0092] FIG. 6b schematically shows a cross-section through a correspondingly coated body 166 with the resulting coating 164 on the substrate 62. The coating 164 comprises a first layer 180a on the substrate 62 with a low proportion of argon and a second layer 180b on top of it with a higher proportion of argon. The first layer 180a is rather ductile and has low internal stress due to the lower proportion of argon, so that it can serve as a good adhesion agent to the substrate 62. The second, outer layer 180b has a high hardness due to the higher proportion of argon. It has been shown that such a layer is particularly suited for tools which are used for demanding machining applications, for example for drilling and milling tools such as end mills, ball end mills, and indexable inserts.

[0093] FIG. 7a, 7b schematically show a second exemplary embodiment with process control that is essentially opposite to the first exemplary embodiment. In the second exemplary embodiment, the delay time T.sub.D is changed from initially 110 μs in a first time interval 270a to 40 μs in a following second time interval 270b. A resulting coating 264 of the coated body 260 has a first layer 280a with a high proportion of argon and a second layer 280b with a lower proportion of argon.

[0094] Such a coating 264 can be advantageous especially for coated bodies 260 which are provided for tribological applications. The first layer 280b serves as a hard base layer with internal stress. The second layer 280b serves as a top layer on top of it, which has good run-in properties due to the higher ductility. Possible applications can include thread-cutting taps, forming taps, drills, and punching and stamping tools.

[0095] FIG. 8a, 8b schematically shows a third exemplary embodiment. The third exemplary embodiment shows a course of the delay time T.sub.D varying in steps in three time intervals 370a, 370b, 370c over the coating duration D. In this case, the delay time T.sub.D increases in steps as in the first exemplary embodiment. A resulting coating 364 of the coated body 360 has a first layer 380a with a low proportion of argon, a second layer 380b with a moderate proportion of argon, and a third, outer layer 380c with a high proportion of argon.

[0096] FIG. 9a, 9b show a fourth exemplary embodiment, in which the delay time T.sub.D and thus also the proportion of argon does not change over the coating duration in steps but gradually, here, for example, in the form of a linearly increasing ramp. The thus generated coating 464 of the coated body 460 shows, accordingly, an argon content increasing from the substrate 62 in the direction towards the surface. The coating 464 thus has only low internal stress in the interface region to the substrate 62, which promotes adhesion. In the region of the surface, the coating 464 has a high hardness, so that it is advantageous in particular for tools for machining applications.

[0097] In FIG. 10a, 10b, a fifth exemplary embodiment with process control opposite to the fourth exemplary embodiment is shown, i.e., the delay time T.sub.D and the argon content in the coating 564 of the coated body 560 become constantly lower over the coating duration D, here in the form of a linearly decreasing ramp.

[0098] FIG. 11a, 11b show a fifth exemplary embodiment, in which the delay time T.sub.D changes abruptly in first time intervals 670a and second time intervals 670b following repeatedly one after another during the coating duration D. During the first time intervals 670a, the delay time T.sub.D is 40 μs and during the second time intervals 670b the delay time T.sub.D is 110 μs.

[0099] The resulting coating 664 of the coated body 660 has as a result first layers 680a with a low argon content and second layers 680b with a higher argon content following alter-nately one after the other in the direction of the layer thickness S. The layer disposed directly on the substrate 62 in the interface region is a first layer 680a with low internal stress, which promotes adhesion. The outermost layer in the region of the surface is a second layer 680b of high hardness.

[0100] The thickness of the layers 680a, 680b is preset by the duration of the time intervals 670a, 670b at a constant layer rate. By selecting the time durations of the time intervals 670a, 670b and the number of switches accordingly, multilayer coatings 664, for example, with a thickness of the individual layers 680a, 680b of, for example, 0.1-2 μm can be generated. Likewise, a nanolayer coating 664 with a thickness of the individual layers 680a, 680b of, for example, 5-50 nm can be generated by switching the time intervals 670a, 670b more quickly.

[0101] The following table 1 shows other exemplary embodiments of coatings:

TABLE-US-00001 Profile of the Ar Layer Layer concentration over Layer No. material structure the layer thickness thickness 1 Al—Ti—N Monolayer, Ramp-like increase up 0.5-20 μm  graded to the surface 2 Ti—B.sub.2 Monolayer, Ramp-like increase up 0.5-5 μm graded to the surface 3 Ti—C—N Monolayer, Ramp-like decrease up 0.5-3 μm graded to the surface 4 Ti—N Monolayer, Ramp-like increase up 0.1-2 μm graded to the surface 5 1st layer Al—Ti—N Two-layer, Decreasing in steps: 1st 1st layer 2nd layer Ti—Al—C—N stepped layer a lot of argon, 2nd 0.5-3 μm layer little argon 2nd layer 0.1-1.5 μm 6 1st layer Al—Ti—N Two-layer, Decreasing in steps: 1st 1st layer 2nd layer Ti—C—N stepped layer a lot of argon, 2nd 0.5-3 μm layer little argon 2nd layer 0.1-1.5 μm 7 1st layer Al—Ti—N Two-layer, Decreasing in steps: 1st 1st layer 2nd layer Ti—C stepped layer a lot of argon, 2nd 0.5-3 μm layer little argon 2nd layer 0.1-1.5 μm 8 As in example 5, Two-layer, Graded decrease: 1st 1st layer 6, or 7 stepped, layer a lot of argon, 2nd 0.5-3 μm graded layer graded reduction 2nd layer transition to less argon 0.1-1.5 μm 9 1st layer Al—Ti—N Two-layer, Increasing in steps: 1st 1st layer 2nd layer Ti—Si—N stepped layer little argon, 2nd 0.5-10 μm layer a lot of argon 2nd layer 0.1-20 μm 10 1st layer Al—Ti—N Two-layer, Increasing in steps: 1st 1st layer 2nd layer Ti—Al—Si—N stepped layer little argon, 2nd 0.5-10 μm layer a lot of argon 2nd layer 0.1-20 μm 11 1st layer Al—Ti—N Two-layer, Increasing in steps: 1st 1st layer 2nd layer Ti—Al—Cr—Si—N stepped layer little argon, 2nd 0.5-10 μm layer a lot of argon 2nd layer 0.1-20 μm 12 1st layer Al—Ti—N Two-layer, Increasing in steps: 1st 1st layer 2nd layer Ti—N stepped layer little argon, 2nd 0.5-10 μm layer a lot of argon 2nd layer 0.1-2 μm 13 1st layer Al—Ti—N Two-layer, Increasing in steps: 1st 1st layer 2nd layer Zr—N stepped layer little argon, 2nd 0.5-10 μm layer a lot of argon 2nd layer 0.1-2 μm 14 1st layer Al—Ti—N Two-layer, Increasing in steps: 1st 1st layer 2nd Ti—N or Zr—N stepped layer little argon, 2nd 0.5-10 μm or C layer a lot of argon 2nd layer 0.1-2 μm 15 1st layer Al—Ti—N Two-layer, Graded increase: 1st 1st layer 2nd layer Ti—Al—Cr—Si—N stepped, layer little argon, 2nd 0.5-10 μm or Ti—C—N graded layer graded increase 2nd layer or Ti—C or C transition up to higher argon 0.1-2 μm content 16 As in example 5, Multilayer Alternating layers with Individual 6, 7, or 15 (more than 2 higher and lower argon layers each layers) content 0.5-2 μm 17 As in example 5, Nanolayers Alternating layers with Individual 6, 7, or 15 higher and lower argon layers each content 5-50 nm

[0102] The coating according to example 1 can be applied, for example, to tools such as milling cutters, drills, indexable inserts, or similar made of steel, stainless steel, or CrMo steel as a substrate material. They are standard layers with little internal stress in the interface region and higher internal stress toward the surface.

[0103] In example 2, they are layers for special applications with little internal stress in the interface region and higher internal stress toward the surface (particularly smooth layers). These can be applied, for example, to tools such as milling cutters, drills, indexable m inserts for machining aluminum, titanium, or non-ferrous metals. Possible applications are demanding machining applications for special materials in which material buildup should be avoided, meaning smooth layers are required.

[0104] According to example 3, the content of argon is high at the beginning of the deposition and is reduced toward the surface. Such layers can be used, for example, for thread-cutting taps, forming taps, drills, or punching and stamping tools. Steel, stainless steel or CrMo steel, for example, can serve as the substrate material. The layers are characterized by a hard base layer with higher internal stress and a soft top layer with good run-in properties and low internal stress. Possible applications of tools with such layers are, in particular, tribological applications.

[0105] In example 4, a graded increase in the argon content toward the surface of the coating takes place, so that it is smooth and visually appealing. Such layers can be used for all types of machining tools and all types of substrate materials. Possible applications are, for example, of a decorative nature. A colored top layer can be applied in a separate process.

[0106] The layers according to examples 5, 6, and 7 provide, on the one hand, a modified composition of the layers following each other and, on the other hand, a modification of the argon content. This can be achieved, for example, in that various HIPIMS magnetron cathodes in the vacuum chamber are fitted with targets made of different materials and controlled separately from each other. By switching off the power supply of a first cathode which is fitted, for example, with an Al—Ti target and simultaneously switching on the power supply of a second cathode which is fitted with a Ti—C target, the change from the first to the second layer, for example, in example 5 can take place. The switching on and off of the correspondingly fitted cathodes can take place abruptly or gradually in the form of a short ramp.

[0107] In example 6, a first cathode is fitted with an Al—Ti target and a second cathode is fitted with a Ti—C target; switching between the cathodes takes place when the layers are changed.

[0108] In example 7, the second cathode is fitted with a Ti—C target and the supply of nitrogen as a reactive gas is switched off at the beginning of the deposition of the second layer.

[0109] In all three examples 5, 6, and 7, the argon content is reduced abruptly at the beginning of the second layer. The layers generated thus can be applied, for example, to tools such as thread-cutting taps, forming taps, drills, punching and stamping tools made of substrate materials such as steel, stainless steel, or CrMo steel. Applications are, for example, tribological applications, for which is it favorable that the generated layers have a hard base layer with internal stress and a softer top layer with good run-in properties and little internal stress.

[0110] The layer according to example 8 can be used for the same types of tools, substrate materials and applications as according to examples 5, 6 and 7. In contrast to the abrupt, stepped reduction in the argon content during the coating duration, according to example 8 the argon content is reduced gradually, i.e., in the form of a ramp.

[0111] The layers according to the examples 9, 10, and 11 also provide a modified composition of the layers, which is achieved by cathodes with different fitting of targets and correspondingly changed electrical control. The layers can be applied, for example, to tools such as end mills, ball end mills, drills, or indexable inserts made of substrate materials such as high-carbon steel, Ni-based alloys, titanium alloys, or stainless steel. Possible applications of the resulting layers, which are hard and smooth (property of the second layer as a functional layer with a high argon content) and have good adhesion (property of the first layer which, with a low argon content, serves as an adhesion agent), are in particular demanding machining applications.

[0112] Examples 12, 13, and 14 can serve for applications such as decorative layers on all types of functional layers or respectively layers for better wear detection. Such layers can thus be applied, for example, in a combined method to other layers as the top finish. All types of machining tools can be considered as substrates, made, for example, of steel, cast iron, CrMo steel, or stainless steel. The lower layer serves as a functional layer and the upper layer as a decorative color layer with, for example, a golden color, which enables good wear detection.

[0113] With a graded transition of the argon content, example 15 represents an alternative for the same applications and substrates as examples 12, 13, and 14. In the mentioned variant with a second layer of carbon (C), a gray top layer is generated, which enables simple visual wear detection.

[0114] In the multilayer layers according to example 16 and the nanolayer layers according to example 17, layers with a high argon content (i.e., high hardness, high internal stress) alternate with those with a low argon content. The constant alternation prevents crack formation and achieves low internal stress of the overall system. Such layers can be provided for all types of machining tools and for substrate materials such as steel, in particular stainless steel, high-carbon steel, CrMo, Ni-based alloys, titanium alloys.

[0115] In summary, the invention can be implemented by various coating methods, coating devices, and resulting coated bodies, wherein the individual embodiments each offer specific advantages for various applications. The embodiments mentioned in detail here each represent examples and are to be understood as illustrative and not restrictive. Various modifications and alternatives to the embodiments shown are possible. For example, the aforementioned embodiments can be implemented with a wide variety of layer materials, i.e., with deviating target fitting and with supplying various reactive gases or also without supplying a reactive gas. The advantage always remains that the resulting coatings can be optimized for the respective applications by controlled setting of properties in various layer regions.