WO2014090909A1

WO2014090909A1 - Wear-resistant layer and method for producing a wear-resistant layer

Info

Publication number: WO2014090909A1
Application number: PCT/EP2013/076297
Authority: WO
Inventors: Stephan Siegmann; Andrew R. Nicoll
Original assignee: Nova Werke Ag
Priority date: 2012-12-12
Filing date: 2013-12-11
Publication date: 2014-06-19
Also published as: JP6038349B2; CN105026601A; DE112013005937B4; KR20150047644A; KR101587391B1; JP2016503125A; DE112013005937A5

Abstract

A wear-resistant layer for a component comprises a filler material and a binder material. The binder material comprises a metallic matrix and the filler material comprises an oxide-ceramic compound, which contains Al₂O₃ - ZrO₂ or Al₂O₃ - TiO₂. The metallic matrix forms a hard matrix with a hardness of 400 HV0.1 to 850 HV0.1. The filler material has a hardness of 1400 HV0.1 to 1800 HV0.1.

Description

WEAR-RESISTANT LAYER AND METHOD FOR

PREPARATION OF A WEAR-RESISTANT LAYER

description

The invention relates to a wear-resistant layer according to the preamble of claim 1 and to a method for producing a wear-resistant layer according to claim 11.

State of the art

The preparation of coatings by thermal spraying is known from the prior art. The methods of thermal spraying are classified in standards EN657 and ISO 14917.

Components made of different base materials can be used for

Provides protection against, for example, wear or corrosion with layers of refractory metals or ceramics. On thermally heavily loaded components can by means of thermal spraying with thermally conductive or heat insulating

Be provided layers. Coating materials used in

Powder mold can be produced, for example, in EN 1274, or those which are producible in wire

For example, in the standard called EN ISO 14919. The

Coating materials are supplied during thermal spraying of a high-energy heat source and melted. The heat source may be a fuel gas-oxygen flame, a

Arc, or a plasma of a noble gas, such as argon,

Include hydrogen, nitrogen or helium. The fused or melted particles are in the direction of the workpiece accelerates and bounces there at high speed, that is, at a speed of about 40 m / s up to and including 600 m / s. After heat transfer to the base material they solidify and form a layer by layer.

EP 1 291 449 A2 discloses a process for coating a friction-prone base material with a protective layer by means of a thermal spraying process. The protective layer consists of an MCrAlY (M = Co, Ni) and a ceramic powder, which is a combination of Al2O3, S13N4, SiC, AlN, Cr3C2,

M0S12, which is supplied in powder form to an injection nozzle and applied to the friable base material. After this process step is a

Diffusion heat treatment is performed and before or after the diffusion heat treatment, the frictional areas of the applied protective layer are cut in a serrated or pointed shape. The diffusion heat treatment is carried out for the example mentioned in EP 1 291 449 A2 at 1150 ° C. in 1 to 10 hours. It serves for improved durability of the

applied protective layer on the base material. In this case, a cohesive connection of the MCrAlY matrix becomes

Basic material achieved.

However, this method is not suitable if the thermal spraying takes place under air supply. In this case, oxygen enters the layer through the air. If there are oxides that are created by the oxygen supply, the layer does not diffuse together. That is, a diffusion treatment loses its effect as soon as oxides are present in the coating. MCrAlY are therefore usually coated under vacuum or protective atmosphere so that the layer contains no oxides. For turbine blades, which consist of a monocrystalline base body, an oxidation-resistant intermediate layer is applied by means of laser deposition welding (LMF) according to EP 2 317 078 A2. This intermediate layer is an MCrAlY having one of the following compositions: (1) 15-30% Cr, 5-10% Al, 0.3-1.2% Y, 0.1-1.2% Si, 0-2% others and the balance Ni, Co, (2) 35-39% Co, 18-24% Cr, 7 - 9% Al, 0.3 - 0.8% Y, 0.1 - 1% Si, 0-2% others and the rest Ni, (3) 18-26% Cr, 5-8% Al, 0.3-1.2% Y, 0.1-1.2% Si, 0-2% others and the remainder Ni, Co (all figures in weight percent). These intermediate layers are optimized for LMF, since the γ-phase initially forms on solidification from the melting phase and this epitaxially solidifies on the base body of the turbine blade.

Following the intermediate layer, an abrasive layer is also applied using LMF. The abrasive layer contains a binder material of the same composition as the intermediate layer and an abrasive material. The abrasive material is completely embedded in the binder material, which extends the useful life of the abrasive layer at high service temperatures. For the application of an abrasive layer on a monocrystalline base material an eptitaktische connection is advantageous, as this is in minimal risk of defect formation. The

Procedure is due to the need of generating a

Melt bath by the laser in the LMF process slowly. The method requires that the powder for the intermediate layer or the abrasive layer is applied to the base body as a focused powder jet. The focused powder jet is guided concentrically around the laser beam and injected into the molten bath. The process is slow, because the molten bath is generated locally, that is pointwise on the surface of the component. According to EP 2 316 988 A1 cubic boron nitride (cBN) (cubic boron nitride) is used as the abrasive material which forms a stable phase structure up to 1100 ° C.-1200 ° C. and does not lose its cutting properties or hardness up to these temperatures. However, cBN is an expensive material, especially in the hard phase version. For coated components that are not used at the above operating temperatures, there is therefore a need for cheaper alternatives. Furthermore, there is a need for an abrasive layer of increased life.

Presentation of the invention

The object of the invention is to provide a wear-resistant layer of higher durability. Another object of the invention is to make the wear-resistant layer faster and cheaper.

The object is achieved by a wear-resistant layer according to claim 1, which is prepared by a method according to claim 1 1.

The inventive wear-resistant layer for a component contains an insert material and a binder material, wherein the

Binder material contains a metallic matrix and the

Insert material contains an oxide ceramic compound. The metallic matrix forms a hard matrix with a hardness of 400 HVO. l up to 850 HVO. l, preferably with a hardness of 600 HVO. l up to 850 HV0.1 and the insert material has a hardness of 1400 HVO. l up to 1800 HVO. l on. The wear-resistant layer may in particular be used as an abrasive protective layer for a component friction surface or contact surface

be used. One function of the abrasive protective layer may be, inter alia, impurities on the

Inner surface of the housing in which the component a

Rotary movement executes, strip. The component can

in particular, be a turbine blade, for example a

Turbine blade of a radial turbine of a turbocharger.

The insert material contains a compound of Al2O3 - ZrO2 or Al2O3 -T1O2. From CN 101580938 it is known to apply Al ₂ O ₃ p in a metallic matrix of NiCrBSi by means of plasma spraying in order to obtain an erosion-resistant coating of a low-alloy C-steel. This layer combination is called

Valve seat surface used, which must be erosion resistant, but not abrasion resistant. That is, this layer must have a high hardness, which is achieved by the use of AI2O3P. It is known from the publication "Fracture Toughness Measurement of Plasma Sprayed Ceramic Coatings" by F. Beltzung et al., Thin Solid Films, 181 (1989) 407-415, that sintered Al 2 O 3 is significantly higher in comparison with plasma sprayed Al 2 O 3

Having fracture toughness. It is also shown that the

Fracture toughness of AI2O3 can be increased if one

at least 20% ZrO2 added. The addition of T1O2 has the opposite effect, the fracture toughness, expressed by the Kc factor, decreases. The publication "Plasma Spray Deposition of Alumina-Based Ceramic Coatings" by H. Filmer et al., CERAMIC BULLETIN, vol.69, NO.12, 1990 appears to confirm the results with respect to plasma sputtered Al2O3-T1O2 layers with 40% T1O2 content However, an addition of 3% T1O2 to an AI2O3 layer appears to increase the Wear resistance. Also from the publication of H. Haas et al, "Thermoshock-resistant plasma-sprayed zirconium oxides and aluminum oxide base coatings" reprint from DVS REPORTS, Volume 98, German Verlag für Schweisstechnik (DVS) GmbH, Dusseldorf (1985), pages 103- 106 is known to use Al ₂ O ₃ - ZrO ₂ or Al ₂ O ₃ - T1O ₂ layers as wear layers, and it is mentioned in this paper that adding 40% of T1O2 to the Al ₂ O ₃ layer leads to a conversion of the stable cx phase The unstable γ- or η-phases come in. If these unstable γ- or η-phases in the structure, it can become a

Chipping the layer come. That means that in the

The observed behavior of the AI2O3 - T1O2 layer is likely to occur only after the addition of 40% T1O2 through the resulting phase transformation. It follows that AI2O3 - T1O2 layers with up to 40% T1O2 can be used as wear layers, if a

Phase transformation is prevented by the process management.

Therefore, the wear resistance is increased in particular with an addition of 20-40% ZrO2, and increased at an addition of up to 40% T1O2, preferably from 1% up to 40% T1O2, in particular 3% up to 20% TiO ₂ .

However, in the preferred application for a blade tip of a turbine blade underlying this invention, not only erosion resistance but also abrasion resistance or wear resistance are required.

The turbine blade tip strips in the operating state of the housing, which may be coated with a squish layer. The

Turbine blade tip comes into contact with this Abstschicht or deposits in the housing, with part of the Abrasive layer or the deposits from the blade tip is scraped off. This can be for the

High temperature operation, for example, a turbocharger

required tight tolerances of blade tip and housing are obtained. Therefore, a wear-resistant coating of the blade tip is needed for this particular application. The wear resistance is obtained by increasing the toughness of the Al 2 O 3 - ZrO 2 or Al 2 O 3 -T 1 O 2 layer compared to an Al 2 O 3 P layer. This surprising increase in

Toughness is due to a microstructure, the one

Crack propagation in the layer largely prevented.

In addition, the porosity of the wear-resistant layer can be at most 5%, preferably at most 3%.

The binder material may contain NiCrBSi or CoCrNiBSi, in particular CoCrNiMoWBSi. The layer consists of one

preferred embodiment of a metallic matrix of a self-fluxing alloy of the type NiCrBSi or CoCrNiBSi (material class 2, i.e. 2.1 to 2.21 according to standard EN 1274,

in particular 2.9: NiCrBSi 74- 15-4-5, in which AI2O3 with ZrO ₂ or AI2O3 incorporated with T1O2.

According to one embodiment, Ni-15Cr-5Si-4B having a grain size of -63 + 16 μπι or Ni-15Cr-5Si-4B with a

Grain size of - 125 + 45 μπι used which a

Insert material of AI2O3 with ZrO2 or AI2O3 with T1O2 contains.

The Al 2 O 3 - ZrO 2 layer according to the exemplary embodiments is in the following composition: (Al 2 O 3) x (ZrO 2) Y R z where X = 100-ZY and 20% <= Y <= 40% and Z <= 1%. Z should denote the usual impurities, such as S1O2, Fe ₂ O ₃ , CaO, TiO ₂ , MgO, Na ₂ O. In particular, 22% <= Y <= 27%. All information is by weight.

According to the exemplary embodiments, the Al 2 O 3 - T1O 2 layer is present in the following composition: (Al 2 O 3) xi (T 2 O 2) YI RZI where XI = 100 - Z 1 -Yl and 3% <= Y 1 <= 40% and Z 1 <= 1%. ZI should be used to denote the usual contaminants, such as

for example, S1O2, Fe2O3, CaO, ZrO2, MgO, Na2O. In particular, Y1 can be 3% or 13%.

The indication of the grain size for Ni-15Cr-5Si-4B has the meaning that 90% of the particles have a particle size of less than or equal to 63 μπι and 10% of the particles have a particle size less than or equal to 16 μπι.

In particular, a grain size of F24 to F220 is used for an Al2O3 - ZrO2 layer or Al2O3 - T1O2 layer. These

Grain size classification is based on a standard prepared by FEPA (Federation Europeenne of the Manufacturers Abrasifs or Federation of European manufacturers of abrasive products and their Trade Associations). The classification indicates the number of stitches per 1 inch (25.4 mm) of the sieve used for the different grain sizes. This is what happens

Grit 150, for example, has just a sieve with 150 meshes per inch in length. The particle size distribution based on those used in this document

Classifications results, looks approximately as follows: F24 = 600 - 850 μιη, F30 = 500 - 710 μπι

F36 = 425-600 μπι, F40 = 355-500 μπι, F46 = 300-425 μπι F54 = 250-355 μπι, F60 = 212-300 μπι, F70 = 180-250 μπι F80 = 150-212 μπι, F 90 = 125-180 μπι, F100 = 106-150 μπι, F120 = 90-125 μπι, F150 = 63-106 μπι, F180 = 53-90 μπι, F220 = 45-75 μπι, F230 = 34-82 μπι, F240 = 28-70 μπι, F280 = 22-59 μπι.

The metallic matrix may contain at least one of the following compounds: NiCuBSi 76 20 with a hardness HRC of 35-40, containing max. 0.05% C, 19-21% Cu, max. 0.5% Fe, 0.9-1.3% B, 1.8-2.0% Si, balance Ni or NiBSi 96 with a hardness HRC of 15-30, containing max. 0.2% C, max. 2.0% Fe, 1.0-4.0% B, 2.0-5.0% Si, balance Ni or NiCrBSi 86 5 with a hardness HRC of 30-35, containing 0.1-0.3% C, 4-6% Cr, 3.0- 5.0% Fe, 0.8- 1.2% B, 2.8-3.2% Si, balance Ni or NiCrBSi 88 5 with a hardness HRC of 30-35, containing 0.1-0.4% C, 3-6% Cr, 1-2% Fe, 1.0-2.2% B, 3.0-4.2% Si, balance Ni or NiCrBSi 83 10 with a hardness HRC of 35-40, containing 0.1-0.3% C, 8-12% Cr, 2.0-4.0% Fe, 2.0-2.8% B, 2.2- 2.8% Si, balance Ni or NiCrBSi 85 8 with a hardness HRC of 30-40, containing 0.1-0.4% C, 6-10% Cr, 1.0-3.5% Fe, 1.4-2.5% B, 2.6- 4.0% Si, Residual Ni or NiCrBSi 80 1 1 with a hardness HRC of 40-50, containing 0.3- 0.6% C, 10-14% Cr, 2.0-4.0% Fe, 2.0-2.8% B, 3.0-4.0% Si, balance Ni or NiCrBSi 74 15 with a hardness HRC of 55-60, containing 0.7- 1.0% C, 15- 17% Cr, 3.0-5.0% Fe, 2.8-3.6% B, 3.5-4.5% Si, balance Ni or NiCrBSi 74 14 with a hardness HRC of 50-55, containing max. 0.05% C, 13-15% Cr, 4.0-5.0% Fe, 2.6-3.6%

B, 4.0-5.0% Si, balance Ni or NiCrBSi 65 25 with a hardness HRC greater than or equal to 60, containing 0.8- 1.0% C, 24-26% Cr, max. 1% Fe, 3.0-3.8% B, 4.0-4.6% Si, balance Ni or NiCrBSi 82 7 with a hardness HRC greater than or equal to 60, containing a maximum of 0.06%

C, 6-9% Cr, 2.5-3.5% Fe, 2.5-3.5% B, 4.0-4.6% Si, balance Ni or NiCrWBSi 64 1 1 16 with a hardness HRC greater than or equal to 50, containing 0.5- 0.6% C , 10-12% Cr, 15-17% W, 3.0-4.0% Fe, 2.2- 2.8% B, 3.0-3.6% Si, balance Ni or NiCrCuMoBSi 67 17 3 3 with one Hardness HRC of 60-65, containing 0. 5-0.8% C, 16-18% Cr, 2-4% Cu, 2-3% Mo, 2.5 - 4.0% Fe, 3.0-4.0% B, 4.0-4.6% Si, balance Ni or NiCrCuMoWBSi 67 17 3 3 3 with a hardness HRC of 55-60, containing 0. 4-0.6% C, 16-18% Cr, 2-4% Cu, 2-3% Mo, 2-3 % W, 3.0- 5.0% Fe, 3.4-4.0% B, 4.0-4.6% Si, balance Ni or NiCoBSi 71 20 with a hardness HRC of 53-58, containing max. 0.05% C, 19-21% Co, max. 0.5% Fe, 2.6-3.2% B, 4.0-5.0% Si, balance Ni or

CoCrNiMoBSi 40 18 27 5 with a hardness HRC of 55-60, containing max. 0.2% C, 26-28% Ni, 18-20% Cr, 4-6% Mo, max. 2.6% Fe, 3.0-3.6% B, 3.0-3.6% Si remainder Co, or CoCrNiMoBSi 50 18 17 6 with a hardness HRC of 30-40, containing 0.1-0.3% C, 17-19% Ni, 18-20% Cr, 6-8% Mo, max. 2.5% Fe, 2.8-3.2% B, 3.3-3.7% Si, balance Co or CoCrNiWBSi 53 20 13 7 with a hardness HRC of 40-50, containing 0.7-1.1% C, 13-16% Ni, 18-21% Cr, 6-10% W, max. 3% Fe, 1.5-2.0% B, 2.0-2.5% Si, balance Co or CoCrNiWBSi 47 19 15 13 with a hardness HRC of 48-52, containing 1.0 - 1.3% C, 13- 16% Ni, 19-20% Cr, 12.5-13.5% W, max. 3% Fe, 1.4-3.2% B, 2.0-3.6% Si, balance Co or CoCrNiWBSi 45 19 15 15 with a hardness HRC of 48-52, containing 1.3 - 1.6% C, 13- 16% Ni, 19-20% Cr, 14.5-15.5% W, max. 3% Fe, 2.8-3.0% B, 2.7-3.5% Si, Rest Co.

A layer with this most preferred

Layer composition is characterized by a higher matrix hardness for coatings, a good bond of the

metallic body on the AI2O3 -ZrO2 grains and an increased proportion of Al2O3 -ZrO2 in the metallic base body.

The binder material may thus contain NiCrBSi or CoCrNiBSi. In particular, the binder material may consist of NiCrBSi. The binder material may also consist of CoCrNiBSi. The proportion of boron may be for each of those mentioned in the preceding sentences Alternatives are at least 0.8 up to and including 4% by weight. The proportion of silicon may be at least 1.8 to 5% by weight. By using the elements boron and silicon, the effect of "self-fluxing" can be achieved, resulting in metallurgical bonding of the metallic matrix to the metal

Basic material results in what normal thermal spraying otherwise only by "shrinkage" and mechanical

"Clamping" of the overheated particles during the impact and cooling process on the base body is done by the effect of "self-flow" are the otherwise typical

Droplet boundaries (fins, "splats") fused in. The objective is to achieve a dense, hard coating

Diffusion heat treatment is not necessary after application of the layer.

The insert material can have a volume fraction of at least 10% up to 40%. In comparison to the prior art, a higher volume fraction can be achieved with the method according to the invention.

The insert material used is in particular a powder which has an average particle size of at least 50 μm. Particularly preferably, the powder may have an average particle size of 70 μπι to 200 μπι. In particular, the powder may have a mean particle size of 70 to 100 μπι.

A component comprises a substrate and a wear-resistant layer according to one of the preceding embodiments. The component may be, for example, a blade, in particular a blade tip for a turbine, for example, for a radial turbine for a turbocharger. Such a blade is particularly suitable for the operation of a rotating

Drive machine with a high peripheral speed.

Such peripheral speeds can be up to 500 m / s, for example, for two-stroke engines for marine use. The blade tips are in frictional contact with static components, such as housing elements, which have deposits through which the blade tips can rub against the static components. In order to strip such contaminants from the surface of the static components, an abrasive wear protection layer according to one of the preceding embodiments is required.

In the method for coating a component with a

wear-resistant layer, a powder containing an insert material and a binder material is supplied to a device for thermal spraying in a first step. The

Binder material contains a metallic matrix and the

Insert material contains an oxide ceramic compound. In a second step, the powder is applied by thermal spraying on the component, whereby a wear-resistant layer is produced. The metallic matrix forms a hard matrix with a hardness of 400 HV0.1 up to 850 HV0.1, preferably 400 HV0.1 up to 750 HV0.1, and the insert material has a hardness of 1400 HV0.1 - 1800 HV0.1 , In particular, insert materials and / or binder materials can be used for the process, wherein the insert materials and / or

Binder materials contain components according to at least one of the preceding embodiments. Preferably, one of the thermal spraying methods mentioned below is used: a plasma spraying method or a flame spraying method.

In one embodiment, the coating is applied to a turbine blade. The turbine blade has a front side (suction side) and a rear side (pressure side). Along the turbine blade, in the operating state, a compressible, in particular gaseous, fluid flows, which is guided from an inlet edge to an outlet edge. The leading edge forms the fluid inlet-side boundary of the front side of the turbine blade. The exit edge forms the fluid outlet-side boundary of the front side of the turbine blade. The leading edge defines the blade tip toward the suction side, wherein the coating according to an embodiment is applied such that in the vicinity of the blade tip (blade outer side) on the front side

(Suction side) a higher layer thickness is achieved than in the vicinity of the blade root (or blade root). After one

Embodiment, the blade ground can not be coated, that is, the blade ground has no coating. The front side is also referred to as the vane suction side. The coating is thus applied primarily on the front edge or suction side, but similar to a snow plow close to the edge on the leading blade surface, that is, the blade tip. In this case, the front edge, in particular the suction side reinforced

be coated. That is, in the region of the leading edge and / or the suction side, according to this exemplary embodiment, there is a layer of increased layer thickness. Hereinafter, the leading edge or suction side or pressure side provided with a layer is referred to as a coated blade surface. The layer can be a variable along the coated blade surface Have layer thickness. In particular, the layer thickness may decrease from the blade tip in the direction of the blade root.

By suitable process management are contrary to

Laser process during thermal spraying all blades coated simultaneously and with the same amount of material.

The ceramic and metal components may either be premixed in their composition, or during the process in

Consistent, increasing or decreasing concentration to homogeneous or graded layers are processed.

In summary, the following advantages of the

Inventive layer, which with a single

Process step, namely by means of thermal spraying, is applied to the base body or the substrate:

A good connection to the main body or the substrate is achieved. The porosity of the binder material forming the metallic matrix is low and closed. The average hardness of 750 HV0.1 is surprisingly well above the

Hardnesses typically achieved by laser deposition welding, which are 420 HV0.1. The liner material may have hardnesses in the range of 1400 to 1800 HV0.1. The insert material may contain particles of different particle size distribution, because the particle size distribution of the insert material has little influence on the porosity, since the melting of the binder material can be a good integration of the particles of the insert material, whereby a good wetting and a good anchoring of the particles can be achieved. The proportion of insert material can also be surprisingly up to about 40 for the reasons mentioned above Vol.% Be increased. The layer may have a high roughness. (Ra = 8 to 10 μπι).

Brief description of the drawings

The used to explain the embodiments

Drawings show:

1 shows a partial view of a blade,

2 shows a detail of the layer in a section at the point I-I,

3 shows Al ₂ O ₃ particles,

4 shows Al ₂ O ₃ with ZrO ₂ particles,

Fig. 5 shows the structure of a layer with AI2O3 insert material, Fig. 6 shows the structure of a layer with Al2O3 with ZrO2

Insert material.

Fig. 7 shows the microstructure of the insert material AI2O3 / ZrO ₂ of

Layer according to FIG. 6

8 shows a comparison of the wear resistance of Al 2 O 3 -

ZrO2 compared to pure Al2O3 or Al2O3 -T1O2

Abrasives.

Basically, the same parts are given the same reference numerals in the drawings.

Ways to carry out the invention

A wear-resistant layer for a component was produced. The wear-resistant layer contains a

Insert material and a binder material, wherein the binder material contains a metallic matrix. The binder material is a self-flowing material with high flowability. The

Insert material contains an oxide-ceramic compound of hard oxide particles of Al 2 O 3 - ZrO 2, or of Al 2 O 3 -T1O 2. The metallic matrix forms a hard matrix with a hardness of 400 HV0.1 up to 750 HV0.1, and the insert material has a hardness of 1400 HV0.1 up to 1800 HV0.1. The hard oxide particles of the

Einlagematerials are sharp-edged grains having a grain size of at least 100 μπι.

Experimental Example 1

By means of thermal spraying, a wear-resistant layer was applied to a blade according to FIG. The

Experimental example according to FIGS. 1 to 4 was carried out with a binder material NiCrSiB and an insert material Al 2 O 3 - ZrO 2.

1 shows a view of a front side 2 of a component,

in particular a blade 1, for example a turbine blade, which can be used for a turbine of a turbocharger. On the front, the suction side 2 of the turbine blade, a wear-resistant layer is applied, which is also referred to as a front layer. The back 3 of the turbine blade, the

Print page, is not visible in the illustration. The suction side 2 and the pressure side 3 are bounded from the outside by the blade tip 6. The blade tip 6 forms with the suction side 2 the

Leading edge 4. The suction side 2 is bounded by the leading edge 7, the trailing edge 8, the blade tip 6 and the blade root 5. In the operating state, along the suction side 2, a compressible, in particular gaseous, fluid flows, which is guided from an inlet edge 7 to an outlet edge 8. The

The leading edge 7 forms the fluid inlet-side boundary of

Front edge 4 of the turbine blade 1 off. The exit edge 8 forms the fluid outlet-side boundary of the leading edge 4 of the turbine blade.

Fig. 2 shows a detail of the layer in a section which runs along the sectional plane I-I, which extends substantially normal to the front. The porosity of the layer is about 2.3%. The hard phase, ie the insert material has a porosity of 15%. From this it can be concluded that the grains of Al 2 O 3 - ZrO 2 are embedded almost completely in the binder material and that due to the self-flowing properties of the binder material a very good binding of the liner material in the binder material on the one hand and on the other hand a very good bonding of the layer takes place to the base material ,

Fig. 3 is an illustration of the insert material AI2O3. Fig. 4 is a picture of the insert material AI2O3 - ZrO2 in 50-fold

Magnification, the representation does not necessarily reflect the measured magnitudes on a scale. These insert materials according to FIG. 3 or FIG. 4 are used in this form, for example for sandblasting. It can be clearly seen that the AI2O3 has a crystalline structure. This crystalline structure entails that the particle is continually crushed during repeated impact events. These repeated impact events correspond to impact events during sandblasting.

The insert material AI2O3 - ZrO2 according to FIG. 4 is present as bulk material with sharp-edged particles which consist of a fine-grained structure. The microstructure of Al2O3 - ZrO2 one has a higher toughness than an insert material consisting of Al2O3. There is a good coating of the surface of the Al2O3 - ZrO2 with the binder material, whereby hardly any voids remain between the insert material and the binder material. The insert material has a similar microstructure, which has also been measured for insert materials of the type AI2O3-ZrO2 used in the sandblasting process. The binder material has only a low porosity. The drop boundaries, which provide for the formation of lamellae when using Al 2 O 3, as shown in FIG. 5, are no longer visible for Al 2 O 3 - ZrO 2 in FIG. 6, since the binder material is completely melted.

FIG. 7 shows a detail view from FIG. 6. The figure shows a section of an Al 2 O 3 -ZrO 2 particle in which a microstructure is visible, which shows the good bonding of the hard oxide phase.

Experimental Example 2

For the embodiment, Ni-15Cr-5Si-4B is replaced with a

Grain size of -63 + 16 μπι used. The fine-grained material is preferred because it must be melted within a single process step. The powder with the selected composition is a self-flowing material, which at the same time a metallic bond with the

Base material of the substrate is received and which no

lamellar structure showing which a crack progress

could favor. The Vickers hardness HV0.3 of the binder material as a metallic matrix measured after the thermal spraying process had an average value of 747 HV0.1.

This hardness is 1.8 times higher than the hardness values that can be achieved by laser deposition welding. The insert material used was either Al 2 O 3 with ZrO 2 or only Al 2 O 3. The particles are usually produced by melting together and then broken to have a sharp-edged surface. It has been found that the layer in which Al 2 O 3 is used with ZrO 2 as the insert material, compared to the layer in which only Al 2 O 3 is used as the insert material, has a lifetime increased by a factor of 2.

Figure 8 shows a comparison of the wear resistance of a powdered AI2O3 - ZrO2 abrasive compared to AI2O3 abrasives 11, 12 and an Al2O3 - T1O2 abrasive 13

Abrasive was carried out a wear test. In such a wear test, resistance of the abrasive to cracks and crushing by breakage is determined. The vertical axis contains the proportion of whole grains in the abrasive, the horizontal axis the number of wear events. The

Wear resistance is defined as the number of entire grains of abrasive present after a number of impacts. Abrasive 13 shows the lowest

Wear resistance, abrasives 10 the largest

Wear resistance. The abrasive 10 consists of eA Ö3 - ZrÖ2. The abrasives 1 1, 12, 13 are powders consisting either of Al 2 O 3 (abrasive 12, high-grade corundum), a mixture of Al ₂ O 3 - ZrO ₂ and ceramics (abrasive 1 1) or have a proportion of T1O2 (abrasive 13, brown Corundum). These results thus show those of Beltzung et al. identified

Effects of low fracture toughness of AI2O3 for

Abrasives and in particular Al2O3 - T1O2 abrasives in comparison to Al2O3 - ZrO2 abrasives whose grain size is subject to wear test has proven to be most resistant to cracking, breakage or crushing. It is also known (see for example

http://www.idsblast.com abrasive-blasting.media) that an AI2O3 abrasive has higher hardness and lower fracture toughness than an AI2O3-T1O2 abrasive, with the AI2O3 abrasive being characterized by higher purity, better cutting properties, a capability the abrasive for self-sharpening, a lower heat, higher thermal stability and higher resistance to acids and bases has. In addition, an influence of the grain size of the abrasive on the

Wear resistance given, as in smaller grains cracks propagate less quickly or due to the smaller grain size, the local crack propagation has less impact on the

Wear resistance of the abrasive has. All curves of Fig. 8 show with increasing number

Wear events a lower rate of comminution of the grains.

Claims

1. A wear-resistant layer for a component, wherein the

Layer contains an insert material and a binder material, wherein the binder material contains a metallic matrix and the insert material contains an oxide-ceramic compound, characterized in that the insert material a

Compound of Al2O3 - ZrO2 or Al2O3 - contains T1O2, wherein the metallic matrix forms a hard matrix with a hardness of 400 HV0.1 up to 850 HV0.1, and that the insert material has a hardness of 1400 HV0.1 up to 1800 HV0.1 having.

2. A layer according to claim 1, wherein the hard matrix has a hardness of 600 HV0.1 up to 850 HV0.1.

3. A layer according to claim 1 or 2, wherein the metallic

Matrix has a porosity of at most 5%, in particular at most 3%.

4. A layer according to any one of the preceding claims, wherein the insert material has a volume fraction of at least 1% up to and including 40%.

5. A layer according to any one of the preceding claims, wherein the insert material is present as a powder, wherein the powder has an average particle size of at least 50 μπι.

6. A layer according to any one of the preceding claims, wherein the insert material is present as a powder, wherein the powder has an average particle size of 70 μπι to 200 μπι.

7. A layer according to any one of the preceding claims, wherein the binder material contains NiCrBSi.

8. A layer according to any one of the preceding claims, wherein the binder material contains CoCrNiBSi.

9. A layer according to claim 7 or claim 8, wherein the proportion of boron is at least 0.8 to 4 wt% inclusive.

10. A layer according to any one of claims 7 to 9, wherein the

Proportion of silicon is at least 1.8 up to and including 5% by weight.

1 1. Component comprising a substrate and a layer according to one of the preceding claims, wherein the component is in particular a blade tip of a turbine blade.

12. A method for coating a component with a

a wear-resistant layer, wherein in a first step a powder comprising an insert material and a binder material is fed to a thermal spraying device, the binder material containing a metallic matrix and the insert material containing an oxide-ceramic compound, the insert material being a compound of Al 2 O 3 - ZrO 2 or Al 2 O 3 - T1O2, wherein in a second step, the powder is applied by thermal spraying on the component, whereby a wear-resistant layer is produced, wherein the metallic matrix, a hard matrix having a hardness of 400 HVO. l up to 850 HVO. l forms and the insert material has a hardness of 1400 HVO. l up to 1800 HVO. l has.

13. The method of claim 12, wherein the thermal spraying is carried out by a plasma spraying method or a flame spraying method.

14. The method of claim 12 or 13, wherein the coating is applied to a turbine blade (1), in particular a blade tip (6) of a turbine blade for a turbocharger.

15. The method of claim 14, wherein the turbine blade (1) has a suction side (2) and a pressure side (3), which are bounded from the outside of a blade tip (6) and the suction side (2) and the blade tip (6) Forming the leading edge (4), wherein the coating is applied such that on the blade tip (6) over the front edge (4) or on the suction side (2) or on the pressure side (3), a layer is applied, wherein the layer has a layer thickness which decreases in the direction of a blade root (5).

16. The method according to claim 15, wherein the turbine blade (1) only in the region of the front edge (4) on the suction side (2).

is coated.

17. The method according to any one of claims 15 or 16, wherein the turbine blade (1) in the region of the blade tip (6) on the suction side (2) and on the pressure side (3) is coated.

18. The method according to any one of claims 15 to 17, wherein the

Blade ground (5) has no coating.