Layer system and component

Abstract

The invention relates to a layer system (1) comprising at least one adhesion promoter layer (2a, 2b) and a plurality of functional layers (3, 4, 5, 6) arranged on the at least one adhesion promoter layer (2a, 2b), each functional layer (3, 4, 5, 6) comprising a first nanolayer (3a, 4a, 5a, 6a) made of a first metal nitride comprising a first metal component and a second nanolayer (3b, 4b, 5b, 6b) made of a metal, each functional layer (3, 4, 5, 6) has a layer thickness d in the range of 1 nm to 100 nm. The invention further relates to a component (100) comprising a metal substrate (10) and a layer system (1) arranged at least partially on a surface of the substrate (10).

Description

[0001] This application is a divisional application of the invention patent application with application number 201780085263.9 (PCT / DE2017 / 101041), application date December 4, 2017, and invention name “Layer system and component”. Technical Field

[0002] The invention relates to a layer system comprising at least one adhesion promoter layer and a plurality of functional layers arranged on the at least one adhesion promoter layer. The invention further relates to a component comprising a metallic substrate and such a layer system arranged on the substrate. The layer system is intended to be used as a wear protection layer. Background Art

[0003] Layer systems and components of the type mentioned at the outset are sufficiently known. In this regard, DE 10 2011 006 294 A1 discloses a method for producing a coated metal component. The layer system applied to the metal component comprises at least one adhesion promoter layer, in particular a metal, and a functional layer. The functional layer is, for example, a nitrided hard material layer or a nanocomposite layer composed of a nitrided hard material and a metal component, the metal component being formed, for example, by elements of the 3rd to 5th main group or the 1st to 8th subgroup of the periodic table of chemical elements.

[0004] WO 2012 / 078151 A1 discloses a nitrided wear protection layer and a component coated with the nitrided wear protection layer. The wear protection layer comprises molybdenum nitride particles distributed in a copper matrix with a particle size in the range of 5 nm to 100 nm, wherein the copper matrix is ​​present in the wear protection layer at 0.1% to 50% by weight and surrounds the individual molybdenum nitride particles.

[0005] It has been found that the composite layers described in the prior art, which comprise a metal matrix and nitrided hard material particles embedded in the metal matrix, although forming a wear protection layer, do not achieve a sufficient reduction in friction relative to the friction object, particularly when using lubricants in the region of the contact surface between the layer system and the friction object. Diamond-like carbon layers (also referred to as DLC layers) form a wear protection layer and provide an effective friction reduction relative to the friction object even when using lubricants, which cannot be observed in the same way in the case of the described composite layers comprising a metal matrix and nitrided hard material particles embedded in the metal matrix. Summary of the invention

[0006] The object of the present invention is to provide a layer system which contains at least one nitrided hard material which serves as a wear protection layer and which leads to a reduction in friction relative to the friction partner during tribo-wear which occurs when using a lubricant. In addition, the object of the present invention is to provide a component which is at least partially coated with such a layer system.

[0007] This task is solved using a layer system, which consists of:

[0008] - at least one adhesion promoter layer; and

[0009] - A plurality of functional layers arranged on at least one adhesion promoter layer, wherein each functional layer comprises a first nanosublayer consisting of a first metal nitride comprising a first metal component and a second nanosublayer (3b, 4b, 5b, 6b) of a metal, wherein each functional layer (3, 4, 5, 6) has a layer thickness d in the range of 1 nm to 100 nm.

[0010] In the sense of the present invention, a "nano sublayer" is understood to be a single layer having a layer thickness in the range of 0.1 nm to 99.9 nm. Here, two nano sublayers together form a functional layer with a layer thickness d. In particular, the layer thickness of the nano sublayer is in the range of 1 nm to 20 nm.

[0011] It has surprisingly been found that the layer system according to the invention provides a high wear protection effect and, moreover, leads to a more effective friction reduction relative to the friction partner when using a lubricant than when using the composite material layers mentioned at the outset.

[0012] In this case, lubricants are understood to mean lubricating oils, lubricating greases, waxes, solid lubricants and the like, and combinations thereof, and also lubricating oils containing customary engine additives.

[0013] It is preferred that the second metallic nanosublayer is formed of at least one metal from subgroups 3 to 7 of the periodic table of chemical elements. It is particularly preferred that the second metallic nanosublayer is formed of at least one metal from the group consisting of copper, palladium, silver, platinum, iridium, gold. In particular, the second nanosublayer is preferably formed of copper.

[0014] Preferably, at least one adhesion promoter layer comprises a first adhesion promoter layer consisting of another metal and a second metal nitride comprising a second metal component. Here, the other metal or the second metal component can be selected to be the same as or different from the first metal component of the first metal nitride of the first nano sublayer. In particular, the first adhesion promoter layer is formed of chromium, chromium-aluminum alloy, titanium, molybdenum or zirconium. Alternatively, it has been confirmed that the first adhesion promoter layer is formed of chromium nitride CrN, titanium nitride TiN, CrAlN or molybdenum nitride MoN.

[0015] The first adhesion promoter layer has a preferred layer thickness in the range of 0.01 μm to 2 μm.

[0016] It is also preferred that at least one adhesion promoter layer comprises a second adhesion promoter layer, wherein the second adhesion promoter layer comprises a first metal component of a first metal nitride arranged in the functional layer and further comprises a further metal or a second metal component contained in the first adhesion promoter layer. The second adhesion promoter layer has a gradient profile in particular, wherein the proportion of the further metal or the second metal component contained in the first adhesion promoter layer decreases in the direction of the plurality of functional layers, and the proportion of the first metal component of the first metal nitride arranged in the functional layer increases accordingly. The second adhesion promoter layer thus forms a transition between the first adhesion promoter layer and a functional layer adjacent to the second adhesion promoter layer.

[0017] The second adhesion promoter layer has a preferred layer thickness in the range of 0.01 μm to 2 μm.

[0018] In this case, preferably, a first adhesion promoter layer is arranged successively, a second adhesion promoter layer is arranged on the first adhesion promoter layer, and a plurality of functional layers are arranged on the second adhesion promoter layer.

[0019] In particular, the number n of functional layers is present in the range of 10 to 10,000, particularly preferably in the range of 100 to 1,000.

[0020] In a particularly preferred embodiment of the invention, the layer system comprising at least one adhesion promoter layer and a plurality of functional layers has a total layer thickness D in the range of 0.1 μm to 10 μm. With such a total layer thickness, on the one hand, excellent adhesion of the layer system to the substrate can be achieved with simultaneously low production times and low process costs, and on the other hand, effective wear protection and friction reduction when using lubricants can be achieved.

[0021] Preferably, the first metal nitride of the first nano-sub-layer is formed by molybdenum nitride MoN. Alternatively, the first metal nitride can also be formed by another nitrided hard material, such as CrN, Cr 2 N, TaN, NbN, TiN, Ti 2 N, ZrN, VN, and AlN are formed.

[0022] It has been found that the first nanometer sublayer of each functional layer is thicker than the second nanometer sublayer associated with this functional layer. As a result, the friction-reducing properties of the layer system can be optimized.

[0023] The sum of the functional layers of the layer system preferably has an average proportion of the metal of the second nanosublayer in the range from 0.1 to 20 atom %.

[0024] The layer system according to the invention is preferably formed by means of a PVD method (PVD=physical vapor deposition) at a temperature of less than 350° C.

[0025] In particular, the layer system has a Vickers hardness in the range of 1000 HV to 4000 HV, thereby ensuring high wear protection.

[0026] The object is further achieved by a component comprising a metallic substrate and a layer system according to the invention arranged at least partially on a surface of the substrate, wherein at least one adhesion promoter layer, in particular a first adhesion promoter layer, is arranged adjacent to the substrate.

[0027] The metal substrate is preferably formed by steel. In particular, steel types such as 16MnCr5, C45, 100Cr6, 31CrMoV9, 80Cr2, 42CrMo4 or the like are preferred.

[0028] The component is designed in particular as a machine component, in particular in the form of a cup tappet, a chain component, a rolling bearing component, a control piston, a bearing sleeve, a rocker arm, a roller tappet component, a plain bearing component or the like.

[0029] For the construction of the layer system by a PVD method (PVD=physical vapor deposition), preferably a device for cathodic atomization is used.

[0030] In a first step, at least one adhesion promoter layer is at least partially applied to at least one substrate. In particular, a first adhesion promoter layer of a metal, for example composed of chromium, is deposited on the surface of at least one substrate. Here, the first adhesion promoter layer can be deposited completely or partially on the substrate.

[0031] Subsequently, a second adhesion promoter layer, in particular composed of chromium and molybdenum, is deposited on the first adhesion promoter layer. In this case, the chromium content preferably decreases starting from the first adhesion promoter layer in the direction of the functional layer.

[0032] In order to construct the functional layer, the substrate is arranged on a substrate holder, for example, which can be rotatable around a vertical axis in the vacuum chamber of the device for cathode atomization. Targets formed by different atomized materials are arranged on the opposite side walls of the vacuum chamber. Here, the working step is described by way of example with the help of the functional layer, which respectively includes a first nano sublayer composed of molybdenum nitride MoN and a second nano sublayer composed of copper. At least one copper target is arranged on the first side wall of the vacuum chamber, and at least one molybdenum target is arranged on the opposite side wall. One or more substrates are arranged on the substrate holder and in the vacuum chamber in a manner that can rotate around a vertical axis, so that each substrate alternately enters the influence area of ​​at least one copper target and the influence area of ​​at least one molybdenum target. Nitrogen as a reaction gas is introduced into the vacuum chamber, and the nitrogen reacts with atomized molybdenum (which is a nitride former) in the region of at least one molybdenum target, and is deposited on the substrate as a first nano sublayer composed of molybdenum nitride MoN. Now, the substrate is rotated by the substrate holder in the direction of at least one copper target, and a second nanolayer consisting of copper Cu is deposited on the first nanolayer formed by MoN, thereby producing a first functional layer. In order to apply another functional layer, the substrate is now further rotated by the substrate holder in the direction of at least one molybdenum target, and another first nanolayer consisting of MoN is formed on the second nanolayer formed by copper. The substrate is rotated again by the substrate holder in the direction of at least one copper target, and another second nanolayer consisting of copper is deposited on the other first nanolayer formed by MoN, thereby producing a second functional layer. Now, a large number of other functional layers are applied in the same way until a total layer thickness D of the layer system in the range of 0.1 μm to 10 μm is preferably reached. Here, the rotation speed of the substrate holder directly affects the layer thickness and the number of nanolayers. The higher the rotation speed is selected when other deposition conditions remain unchanged, the smaller the layer thickness of the nanolayer is, and the higher the number n of nanolayers in the layer system is.

[0033] However, continuous production facilities can also be used for cathode atomization to produce layer systems, wherein the substrate is transported through the vacuum chamber along the travel direction. In addition to the movement along the travel direction, the substrate can also be rotated or turned around its longitudinal axis.

[0034] Some particularly preferred layer systems according to the invention are described below:

[0035] Layer System 1:

[0036] First adhesion promoter layer: chromium

[0037] Second adhesion promoter layer: chromium, molybdenum

[0038] Functional layer: First nanolayer: MoN

[0039] Second nanolayer: Cu

[0040] The functional layer is present here at least 10 times.

[0041] Layer System 2:

[0042] First adhesion promoter layer: chromium

[0043] Second adhesion promoter layer: chromium, niobium

[0044] Functional layer: First nanosublayer: NbN

[0045] Second nanolayer: Cu

[0046] The functional layer is present here at least 10 times. Layer System 3:

[0047] First adhesion promoter layer: chromium

[0048] Second adhesion promoter layer: chromium, titanium Functional layer: First nanometer sublayer: TiN Second nanometer sublayer: Cu The functional layer is present at least 10 times.

[0049] Layer System 4:

[0050] First adhesion promoter layer: chromium

[0051] Second adhesion promoter layer: chromium, tantalum Functional layer: First nanometer sublayer: TaN Second nanometer sublayer: Cu The functional layer is present at least 10 times.

[0052] Layer System 5:

[0053] First adhesion promoter layer: chromium

[0054] Second adhesion promoter layer: chromium, zirconium Functional layer: First nano sublayer: ZrN Second nano sublayer: Cu The functional layer is present at least 10 times.

[0055] Layer System 6:

[0056] First adhesion promoter layer: chromium nitride

[0057] Second adhesion promoter layer: chromium, zirconium Functional layer: First nano sublayer: ZrN Second nano sublayer: Pd The functional layer is present at least 10 times.

[0058] Layer System 7:

[0059] First adhesion promoter layer: chromium nitride

[0060] Second adhesion promoter layer: chromium, molybdenum

[0061] Functional layer: First nanolayer: MoN

[0062] Second nanosublayer: Ag

[0063] The functional layer is present here at least 100 times.

[0064] Layer System 8:

[0065] First adhesion promoter layer: titanium

[0066] Second adhesion promoter layer: titanium, molybdenum

[0067] Functional layer: First nanosublayer: MoN

[0068] Second nanolayer: Au

[0069] The functional layer is present here at least 100 times.

[0070] Layer System 9:

[0071] Adhesion promoter layer: Molybdenum

[0072] Functional layer: First nanolayer: MoN

[0073] Second nanolayer: Cu

[0074] The functional layer is present here at least 10 times.

[0075] Layer System 10:

[0076] First adhesion promoter layer: titanium nitride

[0077] Second adhesion promoter layer: titanium, molybdenum

[0078] Functional layer: First nanosublayer: MoN

[0079] Second nanosublayer: Ir

[0080] The functional layer is present here at least 10 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] The layer system according to the invention and the component in the form of a substrate which is thus at least partially coated should be provided by means of Figure 1 and 2 Explained by way of example. Among them:

[0082] Figure 1 showing a component having a layer system; and

[0083] Figure 2 The device for forming a first layer system on a substrate is shown in a top view in cross section. DETAILED DESCRIPTION

[0084] Figure 1A component 100 is shown having a layer system 1, which is applied to a portion of a surface 10a of a substrate 10. The substrate 10 is formed of steel in this case. Starting from the surface 10a of the substrate 10, the layer system 1 comprises an adhesion promoter layer 2, which comprises a first adhesion promoter layer 2a composed of chromium and a second adhesion promoter layer 2b composed of chromium and molybdenum. The chromium content of the second adhesion promoter layer 2b follows a gradient and decreases from the first adhesion promoter layer 2a in the direction of the functional layers 3, 4, 5, 6. Here, for the sake of clarity, only four of the functional layers provided, which are n=15, are shown. A first functional layer 3 is applied on the second adhesion promoter layer 2b, which comprises a first nano sublayer 3a composed of molybdenum nitride MoN and a second nano sublayer 3b composed of copper Cu located above it. A second functional layer 4 is applied on the first functional layer 3, which also comprises a first nano sublayer 4a composed of molybdenum nitride MoN and a second nano sublayer 4b composed of copper Cu located above it. A third functional layer 5 is applied on the second functional layer 4, and the third functional layer also includes a first nano sublayer 5a composed of molybdenum nitride MoN and a second nano sublayer 5b composed of copper Cu located thereon. A fourth functional layer 6 is applied on the third functional layer 5, and the fourth functional layer also includes a first nano sublayer 6a composed of molybdenum nitride MoN and a second nano sublayer 6b composed of copper Cu located thereon. The total layer thickness D of the layer system 1 is 0.5 μm here. The layer thickness of each functional layer 3, 4, 5, 6 is 15 nm here, wherein each first nano sublayer 3a, 4a, 5a, 6a has a layer thickness of approximately 10 nm, and each second nano sublayer 3b, 4b, 5b, 6b has a layer thickness of approximately 5 nm.

[0085] Figure 2 In the cross-sectional view and in a top view, the method for forming a substrate 10 according to the present invention is only shown by way of example and schematically. Figure 1 The device is shown only schematically and comprises a vacuum container 200 with a vacuum chamber 201, in which a substrate holder 202 is arranged. The substrate holder 202 is a hollow cylinder that can rotate about a vertical axis 205 (see for example the Figure 2 The vacuum container 200 is formed in the form of a hollow cylinder (arrow in the direction of rotation), and a plurality of substrates 10 are fastened on the outside of the hollow cylinder. Targets 203 and 204 are arranged on the opposite side walls of the vacuum container 200 in the vacuum chamber 201. The target 203 is at least one for atomizing molybdenum and constructing the first nano sub-layers 3a, 4a, 5a, 6a (see Figure 1) and the other target 204 is at least one copper target for atomizing copper and forming the second nano sublayer 3b, 4b, 5b, 6b. A negative pressure is adjusted in the vacuum chamber 201, wherein an atmosphere containing nitrogen is present as a reaction gas. In cathode atomization, the molybdenum of the target 203 is atomized and reacts with nitrogen in the vacuum chamber 201. The first nano sublayer 3a, 4a, 5a, 6a composed of MoN is deposited on the substrate 10, and the substrate is respectively located between the target 203 and the substrate holder 202 when the substrate holder 202 rotates. Based on the rotation of the substrate holder 202, the substrate 10 coated with the first nano sublayer 3a, 4a, 5a, 6a is thus transported in the direction of the target 204 until the substrate is located between the target 204 and the substrate holder 202. Now, the second nano sublayer 3b, 4b, 5b, 6b is formed on the first nano sublayer 3a, 4a, 5a, 6a. Further functional layers are applied by further rotating the substrate holder 202 until the desired number n of functional layers is reached.

[0086] Reference numerals list

[0087] 1-Tier System

[0088] 2 Adhesion promoter layer

[0089] 2a First adhesion promoter layer

[0090] 2b Second adhesion promoter layer

[0091] 3, 4, 5, 6 functional layers

[0092] 3a, 4a, 5a, 6a First nanosublayer

[0093] 4b, 4b, 5b, 6b Second nanosublayer

[0094] 10 Base

[0095] 10a Surface of substrate

[0096] 100 Components

[0097] 200 Vacuum container

[0098] 201 Vacuum Chamber

[0099] 202 Base holder

[0100] 203 Target

[0101] 204 Target

[0102] 205 Vertical Axis

[0103] n is the number of functional layers

[0104] d Thickness of functional layer

[0105] D Total layer thickness of the layer system

Claims

1. A layer system (1), comprising - at least one adhesion promoter layer (2a, 2b); and - n functional layers (3, 4, 5, 6) arranged on the at least one adhesion promoter layer (2a, 2b), wherein Each functional layer (3, 4, 5, 6) comprises a first nanolayer (3a, 4a, 5a, 6a) consisting of a first metal nitride comprising a first metal component and a second nanolayer (3b, 4b, 5b, 6b) of a metal, wherein the first metal nitride of the first nanolayer (3a, 4a, 5a, 6a) is formed by molybdenum nitride MoN, and the second nanolayer (3b, 4b, 5b, 6b) of the metal is formed by at least one metal from the group consisting of copper, palladium, silver, platinum, iridium, and gold, wherein each functional layer (3, 4, 5, 6) has a layer thickness d in the range of 1 nm to 100 nm, the at least one adhesion promoter layer (2a, 2b) comprises a first adhesion promoter layer (2a) consisting of another metal or of a second metal nitride comprising a second metal component, and n is selected in the range of 10 to 10000.

2. The layer system (1) according to claim 1, characterized in that The at least one adhesion promoter layer (2a, 2b) comprises a first adhesion promoter layer (2a) consisting of a further metal or of a second metal nitride comprising a second metal component.

3. The layer system (1) according to claim 1 or 2, characterized in that The at least one adhesion promoter layer (2a, 2b) comprises a second adhesion promoter layer (2b) which comprises the first metal component and further comprises either the further metal or the second metal component.

4. The layer system (1) according to claim 3, characterized in that In sequence: the first adhesion promoter layer (2a) is arranged, the second adhesion promoter layer (2b) is arranged on the first adhesion promoter layer (2a), and a plurality of functional layers (3, 4, 5, 6) are arranged on the second adhesion promoter layer (2b).

5. The layer system (1) according to any one of claims 1 to 4, characterized in that The layer system ( 1 ) has a total layer thickness D in the range from 0.1 μm to 10 μm.

6. The layer system (1) according to any one of claims 1 to 5, characterized in that The first nano sublayer (3a, 4a, 5a, 6a) of each functional layer (3, 4, 5, 6) is thicker than the second nano sublayer (3b, 4b, 5b, 6b) associated with the functional layer.

7. The layer system (1) according to any one of claims 1 to 6, characterized in that Each functional layer (3, 4, 5, 6) has a second nanosublayer (3b, 4b, 5b, 6b) consisting of copper.

8. Layer system (1) according to claim 7, characterised in that The sum of the functional layers (3, 4, 5, 6) has an average proportion of the metal of the second nanosublayer (3b, 4b, 5b, 6b) in the range of 0.1 to 20 atomic %.

9. The layer system (1) according to any one of claims 1 to 8, characterized in that The layer system (1) has a Vickers hardness in the range of 1000 HV to 4000 HV.

10. A component (100) comprising a metallic substrate (10) and a layer system (1) according to any one of claims 1 to 9 arranged at least partially on a surface of the substrate (10), wherein: At least one adhesion promoter layer (2a, 2b) is arranged adjacent to the substrate (10).

11. The component according to claim 10, wherein The substrate (10) is formed from steel.

12. A component according to claim 10 or 11, wherein: The component is designed as a machine component, in particular in the form of a cup tappet, a chain component, a rolling bearing component, a control piston, a bearing sleeve, a rocker arm, a roller tappet component or a plain bearing component.

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