WO2020064041A1

WO2020064041A1 - Method for producing a multiple-coat anti-erosion and anti-corrosion coating, and component with a corresponding protective coating

Info

Publication number: WO2020064041A1
Application number: PCT/DE2019/000252
Authority: WO
Inventors: Stefan Schneiderbanger; Ralf Stolle; Thomas Uihlein; Philipp Utz; Wolfgang Eichmann
Original assignee: MTU Aero Engines AG
Priority date: 2018-09-27
Filing date: 2019-09-25
Publication date: 2020-04-02
Also published as: DE112019004858A5; DE102018216658A1

Abstract

The present invention relates to a method for producing a multiple-coat anti-erosion and anti-corrosion coating with a plurality of metal layers (2, 4) and ceramic layers (3, 5), wherein: the metal and ceramic layers are deposited alternately; one of the metal layers is deposited on a base material (1) of a substrate; and the metal layers and the ceramic layers are deposited by physical vapour deposition, with the base material (1) first being plasma etched and a Cr layer then being deposited as the metal layer (2, 4) and subsequently a layer predominantly consisting of CrAIN being deposited as the ceramic layer (3, 5), and with the ceramic layer (3, 5) being deposited as a CrAlN layer with embedded CrN nanolayers (6) with the addition of nitrogen and the use of a Cr Al target and a Cr target and/or the base material being selected from the group comprising Fe, Ni, and Co alloys and ceramic composite materials and fibre-reinforced ceramics. The invention also relates to a correspondingly coated component.

Description

METHOD FOR PRODUCING A MULTILAYER EROSION AND CORROSION PROTECTIVE LAYER AND COMPONENT WITH A CORRESPONDING

PROTECTIVE LAYER

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The present invention relates to a method for producing a multilayered erosion and corrosion protection layer with several metal layers (2, 4) and ceramic layers (3, 5), the metal and ceramic layers being deposited alternately and one on a base material (1) One of the metal layers is deposited on the substrate and the deposition of the metal layers and the ceramic layers takes place by physical vapor phase deposition (PVD physical vapor deposition). In addition, the invention relates to a correspondingly manufactured component, in particular a component of a turbomachine, such as an aircraft engine.

STATE OF THE ART

Components of turbomachines, such as stationary gas turbines or aircraft engines, in particular rotor blades, guide vanes or turbine linings (so-called shrouds) are exposed to a variety of influences during operation, which lead to components of this type having to have different properties. Such fluid mechanically loaded components are subject to increased wear as a result of oxidation, corrosion and erosion, so that appropriate wear protection coatings are required in order to extend the service life of the appropriate components to increase. Various proposals have already been made for this purpose, as described, for example, in document EP 2 398 936 B1.

These anti-wear coatings or anti-erosion coatings usually have multilayer coatings that consist of a sequence of layers of soft and hard materials. In addition, it is known to form these coatings, for example on a chromium basis, so that the high proportion of chromium causes oxidation

- And corrosion protection effect is achieved. For example, EP 3 246 430 A1 proposes a layer sequence of a metal layer, a metal alloy layer, a metal-ceramic gradient layer and a nanostructured ceramic layer, which can be deposited by cathode sputtering (sputtering) or by cathodic arc deposition (CatArc) . The metal layer can be made of a Cr layer, the metal alloy layer can be made of a CrNi layer, and the metal-ceramic gradient layer can be made of Cr _x Al _lx N

- Layer as well as the nanostructured ceramic layer from ceramic partial layers of CrAlN and CrN are formed. The deposition of AlCrN layers on tools is known from the publication of the international application WO 2004/059030 A2, while the German patent application DE 10 2009 013 129 A1 discloses an erosion protection layer for plastic components.

Even though erosion protection layers are already known, through which a good protective effect is achieved, a further optimization of corresponding erosion and corrosion protection layers is necessary so that an optimal compromise between the different protection effects and a cost-effective and efficient production can be achieved.

DISCLOSURE OF THE INVENTION

OBJECT OF THE INVENTION It is therefore an object of the present invention to provide a method for producing an erosion and corrosion protection coating which has a balanced profile of properties and can be produced in a simple and inexpensive manner. In particular, a correspondingly produced coating should have a high resistance to erosion attack or good mechanical properties against fatigue.

TECHNICAL SOLUTION

This object is achieved with a method with the features of claim 1 and a component with the features of claim 11. Advantageous refinements are the subject of the dependent claims.

According to the invention, a multi-layer erosion and corrosion protection layer is proposed, which comprises a plurality of metal layers and a plurality of ceramic layers, the metal and ceramic layers alternatingly following one another and one of the metal layers being deposited on a base material of a substrate or component. In particular, the coating according to the invention can have a multiplicity of individual metal and ceramic layers which can be deposited alternately one above the other on the substrate or component, but starting with the metal layer.

According to the invention, the metal layer and the ceramic layer are to be deposited by physical vapor phase deposition, in particular plasma-assisted physical vapor phase deposition, wherein first a plasma-assisted etching of the base material of the component to be coated takes place and then a Cr layer is deposited as a metal layer on the base material and subsequently immediately as a ceramic layer, a layer that predominantly has CrAlN. The etching of the base material by means of plasma-assisted etching ensures that the coating is well bonded and thus that the coating adheres well to a wide variety of base materials, such as iron alloy genes, nickel alloys, cobalt alloys or ceramic composite materials such as fiber-reinforced ceramics. However, the plasma-assisted etching can be carried out in a simple manner in the same processing chamber as the subsequent deposition of the coating, in particular by means of plasma-assisted physical vapor phase deposition, so that production is simplified. At the same time, the one or more Cr layers and the one or more CrAlN or ceramic layers of the layer composite, which are alternately deposited, offer excellent oxidation and corrosion resistance and erosion resistance.

The deposition of the metal layer (s) and the ceramic layer (s) can be carried out immediately after the etching, so that the substrate or component no longer has to be exposed to the ambient atmosphere between the etching and the deposition of the coating, so that the surface cannot be oxidized.

According to one aspect of the invention, the erosion and corrosion protection layer can in particular be applied to a component which is formed from a base material which is selected from the group comprising Fe, Ni, Co alloys and ceramic composite materials and fiber-reinforced ceramics. In particular, the erosion and corrosion protection layer can be applied directly to the base material.

According to a further aspect of the invention, for which protection is sought independently and in combination with other aspects of the invention, the CrAlN ceramic layer can be embodied with embedded CrN nano-layers, the CrN-nano-layers being able to cause particle solidification of the ceramic layer and at the same time obstacles for can represent a crack progress.

The plasma-assisted etching before the layers are applied can be carried out by sputtering the substrate, by ion etching, reactive ion etching or ion beam etching. It is particularly advantageous to have a coating system, such as a sputter system or to operate a system for arc evaporation in such a way that cathode sputtering of the substrate or of the base material of the component to be coated can take place for the etching. This can be achieved, for example, by applying a corresponding bias voltage with a negative potential to the substrate, so that positively charged ions from the ignited plasma in the processing chamber are accelerated onto the substrate to be coated and material is removed there. Subsequently, the coating of the substrate can be started immediately in a corresponding processing system by lowering the bias voltage and sputtering appropriate targets, ie a Cr target for the coating with a Cr layer and / or a CrAl target for the deposition of a CrAlN layer.

For the production of a Cr layer, a Cr target can be used which consists of technically pure chromium and in particular has at least 95% by weight of chromium, preferably at least 99% by weight of chromium, so that a corresponding Cr layer is formed, in which the proportion of other constituents is less than or equal to 5% by weight or less than or equal to 1% by weight. Alternatively, the metal layer can also be designed as a Cr alloy layer with a predominant proportion of chromium, for example a proportion of more than 50% by weight of chromium.

The ceramic layer can be designed as a CrAlN layer, a CrAl target being able to be sputtered by cathode sputtering or arc evaporation and, at the same time, nitrogen can be let into the processing chamber, so that a corresponding nitride is formed. The CrAl target can have a proportion of 64 to 67% by weight of chromium and 33 to 36% by weight of aluminum.

The CrAlN layer can have a chemical composition with a Cr content of 30 to 34 at.%, An Al content of 18 to 22 at.% And the remainder N, the chemical composition being determined in particular by energy-dispersive X-ray spectroscopy (EDX) . The increased Cr content compared to a CrAl target used can result from introduced nano-layers of CrN. The CrN nanolayers in the CrAlN layer can be deposited by sputtering or evaporating the Cr target next to the Cr Al target, wherein the Cr target can be sputtered or evaporated continuously or only temporarily or intermittently. Correspondingly, CrN nanolayers can form, which are embedded in the ceramic layer as a continuous layer along the component or substrate surface or as isolated nanoparticles, with layer thicknesses or particle sizes in the CrN nanolayer layers in the direction of the layer thickness, i.e. transversely to the component surface , from 1 to 100 nm, preferably 5 to 50 nm.

The individual layers, that is to say the metal layer (s) and the ceramic layer (s), can be continuously deposited in succession or a pause can be inserted in which the processing chamber can be cleaned by evacuation in order to mix the composition of the individual Avoid layers as much as possible.

The one or more metal layers can each have a layer thickness of 10 nm to 2 pm and the ceramic layers can each have a layer thickness of 200 nm to 20 pm. The total layer thickness of the erosion and corrosion protection protective layer can be 2 pm to 100 pm.

The individual metal layers and ceramic layers can each be deposited in the same way or in a different way, which concerns both the formation of the individual layers and the deposition process.

BRIEF DESCRIPTION OF THE FIGURES

The attached drawings show in a purely schematic manner in

1 shows a cross section through part of a component with a first embodiment of a coating according to the invention and in FIG. 2 shows a cross section through part of a component with a second embodiment of a coating according to the invention.

EXEMPLARY EMBODIMENTS Further advantages, characteristics and features of the present invention will become apparent in the following detailed description of the exemplary embodiments. However, the invention is not restricted to these exemplary embodiments.

FIG. 1 shows in a purely schematic representation a part of a component on which a coating according to the invention is applied. The component has a base material 1 on which a Cr layer 2 is deposited, a ceramic layer 3 made of CrAlN being subsequently formed on the Cr layer 2 in the direction of the outside of the component. The partial coating of the metal layer 2 and the ceramic layer 3 is applied several times, so that a second metal layer 4 in the form of a Cr layer and a second ceramic layer 5 made of CrAlN are arranged above the ceramic layer 3. FIG. 2 shows a further exemplary embodiment of a coating according to the invention, in which a sequence of alternately arranged metal layers 2, 4 and ceramic layers 3, 5 is again provided on a base material 1. As in the exemplary embodiment in FIG. 1, in the exemplary embodiment in FIG. 2 the metal layers 2, 4 are formed from Cr layers, while the ceramic layer 3, 5 is formed by CrAlN layers. In contrast to the exemplary embodiment in FIG. 1, however, 3.5 CrN nanolayers 6 are embedded in the CrAlN layers in the coating in FIG. The CrN nano-layers 6 can be present as continuous partial layers along or parallel to the surface of the corresponding component or as individual nanoparticles, so that the CrN-nano-layers 6 are not continuously provided as a layer along or parallel to the surface of the component. The corresponding layers can be applied to the substrate to be coated in a plasma-assisted PVD system, for example in a system for cathodic arc evaporation (CatARC) with an additional sputtering function.

The method for producing the coating according to the invention first provides for cleaning the base material 1 or the surface of the substrate or component on which the coating is to be applied. The cleaning can be done by ultrasound and / or by blowing with inert gases such as argon. The surface of the base material to be coated is then subjected to an etching process, in particular an ion etching process. The etching can be carried out by plasma-assisted etching, the substrate to which the coating is to be applied, for example, being used as a target for cathode sputtering. In addition, the etching of the base material 1 can be carried out by ion etching, reactive ion etching or ion beam etching. For example, a so-called bias voltage in the range from 400 to 1000 V with negative potential can be applied to the component or substrate with the base material 1 to be coated, so that when the plasma is ignited in the processing chamber, ions of the plasma are accelerated onto the substrate and remove material there when hitting (sputtering). At the same time, one or more targets located in the processing chamber for the subsequent coating can be given a low negative potential in order to avoid unwanted coating of the targets during the etching and to provide further metal ions for the etching process . For example, a current of 50 to 200 A, preferably 50 to 180 A, can be preselected on a chrome target, which can be provided for the subsequent coating with a Cr layer in the processing chamber, so that a negative Voltage in the range of 10 to 40 V, in particular 13 to 25 V are set. For a CrAl target, which is used for the subsequent coating of a CrAlN layer, a negative voltage in the range from 0 to 50 V, in particular 13 to 25 V, can be applied, so that a current intensity of 50 at the CrAl target up to 31000 A, preferably 110 to 8200 A, so that a negative voltage in the range of 0 to 50 V, in particular 13 to 25 V, arises at the CrAl target. In this case, the current flow at the chrome target can be in the range from 90 to 185 A, in particular 110 to 150 A can be selected, while a current flow of 15 to 40 A, in particular 5 to 15 A, can be set on the substrate to be coated. This is influenced by the surface of the substrate and can vary accordingly.

In etching an argon can - atmosphere less than or equal to 0.5 at a pressure * are 10 ⁴ to 5 10 ² mbar is set especially in the range of 0.5 * l0 ³ mbar, with a working gonzufluss of 5 to 200 sccm (Standard cubic centimeters per minute), in particular 10 to 200 sccm can be set in the processing chamber. The temperature in the processing chamber can be set between 200 ° C and 500 ° C.

Subsequent to preparing the surface to be coated by etching, the deposition of the metal layer 2, that is to say the Cr layer, can begin immediately. For this purpose, the bias voltage on the substrate to be coated can be reduced to 0 to 500 V, in particular 20 to 100 V, for example by stepwise lowering in steps of 50 to 100 V. At the same time, a current flow on the chrome in the range of 90 can occur at the chrome target up to 250 A, in particular 150 to 220 A, so that a negative voltage in the range of 10 to 50 V, in particular 13 to 25 V, results at the chrome target, while the current flow on the substrate decreases to 5 with the reduced bias voltage up to 40 A, in particular 5 to 15 A. During the deposition of the Cr layer, an argon atmosphere with a pressure of 5 * 10 ² mbar, in particular in the range from 1 * 10 ³ mbar to 5 * 10 ² mbar, with a flow rate of the argon gas in the range from 5 to 200 sccm, in particular 10 to 100 sccm can be set. The temperature can be selected in the range from 200 ° C to 500 ° C, in particular 250 ° C to 500 ° C.

After the Cr layer 2 has been deposited, a CrAlN layer 3 is deposited, the processing chamber being able to be evacuated between the deposition of the two layers, for example for a period of 3 h, in order to prevent excessive mixing in the transition region of the Layer compositions takes place. However, it is also possible for the change from the deposition of one layer to the other layer to take place continuously, the deposition conditions being changed continuously or stepwise or one target is switched to the other target, which are advantageously located in the same processing chamber. For this purpose, the bias voltage on the substrate is set to a negative voltage of 10 to 100 V, in particular 15 to 40 V and a current flow of 5 to 100 A, preferably 5 to 50 A, while a current of at the CrAl target 10 to 800 A, in particular 150 to 800 A, and a negative potential of 10 to 50 V, in particular 13 to 25 V, are set. In addition to the argon atmosphere, nitrogen is introduced into the processing chamber for the formation of nitrides. The nitrogen can be supplied at an inflow rate of 200 to 1000 sccm, in particular 400 to 800 sccm, while the argon supply is set to 0 to 300 sccm, in particular 0 to 100 sccm. The pressure in the processing chamber is in turn selected in the range from less than or equal to 5 * 10 ¹ mbar, in particular in the range from 1 * 10 ³ mbar to 5 * 10 ² mbar, the temperature in the range from 200 ° C. to 500 ° C. is in particular 250 ° to 500 ° C.

In addition to the sputtering of the CrAl target to form the CrAlN layer 3, a Cr target can also be sputtered, so that there is a so-called CrN nano-layer, ie the formation of Cr nano-layers 6 in the CrAlN layer 3. The Cr target can be operated continuously or only intermittently or intermittently, a current flow at the Cr target of 0 to 250 A, in particular 0 to 200 A, and a negative voltage in the range of 0 to 50 V, in particular 13 to 25 V.

Although the present invention has been described in detail with reference to the exemplary embodiments, it is obvious to the person skilled in the art that the invention is not limited to these exemplary embodiments, but rather that modifications are possible in such a way that individual features are omitted or other combinations of Features can be realized without leaving the scope of the appended claims. In particular, the present disclosure includes all combinations of the individual features shown in the various exemplary embodiments, so that individual features that are only described in connection with one exemplary embodiment are also included in other exemplary embodiments or combinations of individual features that are not explicitly illustrated. can be set. REFERENCE SIGN LIST

1 base material (substrate)

2 metal layer (Cr layer) 3 ceramic layer (CrAlN layer)

4 metal layer (Cr layer)

5 ceramic layer (CrAlN layer)

6 CrN nano layers

Claims

EXPECTATIONS

1. Method for producing a multi-layer erosion and corrosion protection layer with several metal layers (2,4) and ceramic layers (3,5), whereby the metal and ceramic layers are alternately deposited and one of the substrates on a base material (1) Metal layers is deposited and the deposition of the metal layers and the ceramic layers takes place by physical vapor phase deposition,

wherein a plasma-assisted etching of the base material (1) takes place and then a Cr layer is deposited as a metal layer (2, 4) and then a layer, which predominantly has CrAlN, is deposited as a ceramic layer (3, 5) and wherein

the ceramic layer (3,5) is deposited as a CrAlN layer with embedded CrN nanolayers (6) with the addition of nitrogen and using a Cr Al target and a Cr target,

and or

the base material is selected from the group consisting of Fe, Ni, Co alloys and ceramic composites and fiber reinforced ceramics.

2. The method according to claim 1,

characterized in that

several metal and ceramic layers are alternately deposited, the deposition being carried out identically or differently for several layers of the same type.

3. The method according to any one of the preceding claims,

characterized in that

the etching and the deposition are carried out in the same processing chamber for the etching and the deposition and / or excluding the contact of the substrate with the ambient atmosphere between the etching and the deposition.

4. The method according to any one of the preceding claims,

characterized in that

for the plasma-assisted etching, at least one method is selected from the group comprising cathode sputtering of the substrate, ion etching, reactive ion etching and ion beam etching.

5. The method according to any one of the preceding claims,

characterized in that

the physical vapor phase deposition takes place as plasma-assisted physical vapor phase deposition by cathode sputtering or arc vaporization of a target.

6. The method according to any one of the preceding claims,

characterized in that

the Cr layer is deposited as a pure Cr layer, in particular with a proportion of other constituents of less than or equal to 5% by weight, or as a Cr alloy layer with a predominant proportion of Cr.

7. The method according to any one of the preceding claims,

characterized in that

the ceramic layer (3,5) is deposited as a CrAlN layer with the addition of nitrogen and the use of a CrAl target.

8. The method according to any one of the preceding claims,

characterized in that

the CrN nanolayers (6) are embedded as individual nanoparticles in the CrAlN layer and / or the CrN nanolayers have layer thicknesses of 1 to 100 nm, preferably 5 to 50 nm.

9. The method according to claim 8,

characterized in that

during the deposition of the ceramic layer (3, 5), the Cr target is only subjected to voltage temporarily or intermittently.

10. The method according to any one of the preceding claims,

characterized in that

the metal layer (2, 4) and the ceramic layer (3, 5) are continuously deposited one after the other or after interposed breaks for cleaning a processing chamber in which the deposition takes place.

11. Component with a base material (1) and an erosion and corrosion protection layer deposited on the base material, in particular according to the method according to one of the preceding claims, which comprises a plurality of metal layers (2, 4) and a number of ceramic layers (3, 5) , the metal and ceramic layers alternatingly following one another and one of the metal layers being deposited on the base material, a Cr layer being deposited as the metal layer and immediately thereafter as a ceramic layer a layer which predominantly has CrAlN,

and where

the ceramic layer (3, 5) is designed as a CrAlN layer with embedded CrN nano-layers (6),

and or

12. Component according to claim 11,

characterized in that

the metal layers (2,4) each have a layer thickness of 10 nm to 2 pm and / or the ceramic layers (3,5) each have a layer thickness of 200 nm to 20 pm and / or the erosion and corrosion protection layer has an overall layer thickness of 2 pm to 100 pm.

13. Component according to one of claims 11 to 12,

characterized in that

the CrN nanolayers are embedded as individual nanoparticles in the CrAlN layer and / or the CrN nanolayers have layer thicknesses of 1 to 100 nm, preferably 5 to 50 nm.

14. Component according to one of claims 11 to 13,

characterized in that

the CrAlN layer has a chemical composition with a Cr content of 30 to 34 at.%, an Al content of 18 to 22 at.% and the remainder N, the chemical composition being determined in particular by energy-dispersive X-ray spectroscopy.

15. Component according to one of claims 11 to 13,

characterized in that

the component is a component of a turbomachine, in particular an aircraft engine, preferably selected from the group comprising rotor blades, guide vanes, flow channel boundaries and blisks.