DE102008056741A1 - Wear protection layer for Tial - Google Patents

Abstract

The present invention relates to a wear-protected component for high-temperature applications of a TiAl material, in particular a turbine blade with a protective layer (2) having at least two layers, wherein a first diffusion barrier layer (2) made of a noble metal and a second hard material layer (3) with hard material particles, in a Precious metal matrix are embedded, are applied to the TiAl material (1) as a protective layer and a corresponding manufacturing process.

Description

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The The present invention relates to a wear-resistant Component made of a TiAl material for high temperature applications with a two-layer protective layer and a method for its production and the corresponding application with a turbine blade.

STATE OF THE ART

TiAl materials, ie materials based on γ-titanium aluminide, α ₂ -Ti ₃ Al and corresponding alloys are interesting because of their low weight for use in gas and turbine construction.

Indeed need these materials, especially for Turbine blades find use, a protection against wear and / or corrosion-related degradation. So exists for example in the Arrangement of TiAl turbine blades on rotors made of nickel materials the risk of damage by fretting, ie the combination from fretting and corrosion.

in the Airfoil area can be influenced by environmental factors, for example when using turbines in sandy or dusty areas, erosion occur as a damage mechanism.

Furthermore, such turbine blades are often designed so that they seal with their free ends against sealing surfaces, so-called sealing fins, wherein the ends of the turbine blades grind to produce a good sealing effect, so that at the ends of the turbine blades abrasive wear can occur. For example, in the DE 37 88 116 T2 . EP 0 166 676 A2 and the CA 2 411 156 A1 Abrasive materials for turbine blade ends described.

At the same time there are temperature or corrosion protection layers, as in the US 5,413,871 or the JP 2003269105 A described.

The US 5,116,430 and the US 5,154,816 describe wear protection layers for titanium materials in which in particular nickel layers are seen under a wear protection layer with hard, especially ceramic particles before. However, there is the problem with these layer systems that in high-temperature applications, such as in the application of titanium aluminides in turbines, by the diffusion of components of the layer material in the base material, the base material can be changed or impaired in an inadmissible manner.

DISCLOSURE OF THE INVENTION

OBJECT OF THE INVENTION

It Therefore, the object of the present invention is a protective layer for TiAl materials or corresponding components, in particular To provide turbine blades and a method of making the same, which avoids the problems of the prior art.

Especially should a TiAl component or a corresponding protection system for provided a TiAl material and a method for its production which are safe in high temperature applications before wear of various types, such. As erosion, fretting, or wear in the Associated with corrosion phenomena prevented, with the protective layer safe and easy to produce during operation.

TECHNICAL SOLUTION

These Task is solved by a wear-resistant Component with the features of claim 1, a method for manufacturing a corresponding component with the features of claim 15 and in particular a turbine blade with the features of Claim 20. Advantageous embodiments are the subject of the dependent Claims.

The invention is characterized in that on a TiAl material, ie a material based on the intermetallic phases γ-TiAl, α ₂ -Ti ₃ Al and alloys thereof, an at least two-layer or two-layer protective layer system is provided which comprises a first diffusion barrier layer comprising a noble metal and a second hard material layer with hard material particles, wherein the hard material particles are embedded in a noble metal matrix.

One Such a two-ply layer system offers the possibility a diffusion of components of the protective layer, ie in particular the elements of the hard particles, to prevent in the TiAl at the same time the ductile noble metal prevents crack growth or at least hindered, so that the mechanical properties and in particular, the vibration resistance of the component are not impaired.

The hard material particles, which are embedded in the precious metal matrix in the hard material layer, provide the necessary hardness and resistance For example, erosion or abrasive wear and the like ready, the incorporation of the hard particles in a noble metal or the coating of the individual particles by precious metal, the risk of cracking and growth and thus negative effects on the mechanical properties of the entire coating or on the entire composite materials reduce or avoid.

The term of the TiAl material used here generally includes the intermetallic phases of the TiAl, ie in particular γ-Titanalumind or α ₂ -Ti ₃ Al and also corresponding alloys, for example with niobium or the like. In addition, the respective materials may include companion elements such as nitrogen, carbon, oxygen, hydrogen, and the like.

The Precious metals for the diffusion barrier layer or the precious metal matrix include the platinum metals, gold, silver, mercury and rhenium, so in particular ruthenium, rhodium, palladium, silver, rhenium, osmium, Iridium, platinum, gold and mercury being in particular the use of Palladium, silver, osmium, platinum and gold come into question.

The Hard material particles of the hard material layer can in particular Nanoscale be formed by its size already avoid the formation of cracks or crack growth. Especially can the hard material particles of the hard material layer a average or maximum grain size of 500 nm or less, in particular 250 nm or less, preferably 100 nm or have less.

The Hard material particles can be made of a ceramic material or other hard material, in particular alumina, Zirconia, diamond, diamond-like carbon, boron nitride, cubic boron nitride (CBN), titanium nitride, titanium-aluminum nitride, Silica, in particular silicon dioxide and silicon carbide and like.

The Protective layer can, in particular on the above-described, in principle be limited to two-layer or two-layer structure, wherein the diffusion barrier layer and the hard material layer on formed in multiple layers or different sub-layers could be.

Especially The diffusion barrier layer can be applied directly to the TiAl material be arranged and / or the hard material layer as a surface layer be educated.

The Diffusion barrier layer can have a thickness of 0.5 μm to 10 μm, in particular 1 .mu.m to 3 .mu.m, preferably about 1 .mu.m to 2 microns, while the hard material layer a thickness of 0.1 μm to 100 μm, preferably 0.1 μm to 10 μm, most preferably 0.2 to 0.8 microns, in particular about 0.5 microns can.

The Protective layer can in particular by an adaptation of the hard material layer be adapted to different conditions of use. So can for example, the chemical composition of the hard material particles used, the size of the hard material particles and / or their Shares in the hard material layer can be varied. For a Component can be given this variation along the thickness of the hard material layer so that the protective layer and in particular the hard material layer may be formed in the form of a gradient layer. In addition, it is also conceivable that discrete areas with different formations of the hard material layer on one Component be arranged. In addition, you can these areas also merge into each other continuously.

The respective layers can be deposited on the TiAl material in any suitable manner. In particular, however, an organic noble metal compound can be used, which can be applied with or without solvent on the TiAl material. Examples of organometallic compounds containing noble metals are e.g. B. in the E2 0 456 908 A called.

The in the applied layer existing solvents can be evaporated by the action of temperature. At the same time can at the temperature treatment, the organic precious metal compound cracked so that correspondingly volatile components are formed and only the precious metal remains on the treated surface. This can in a very simple way a thin diffusion barrier layer be formed from a precious metal.

In In the same way can thereby a hard material layer form. In this case, only need to organic Noble metal compound or to the mixture of organic noble metal compound and solvents the hard material particles are dispersed, so that the hard particles after the temperature treatment in the deposited noble metal layer remain.

at The term solvent used here may be used to act on any solvent with which the organic Precious metal compound can enter into a solution, for example also about water.

Of the Solvent content may also vary accordingly to the Properties of the deposited noble metal layer or the noble metal layer with to influence dispersed hard material particles.

For the application of the organic noble metal compound with or without Solvent or with or without hard particles can all suitable application techniques are used, in particular Techniques from the field of painting technology, such as brushing, spraying and the same.

The Diffusion barrier layer and the hard material layer can be applied separately in succession or parts of the treatment, such as to go through the temperature treatment together. In this case, the corresponding organic noble metal compounds with or without solvent and once with and without the corresponding hard material particles in succession in liquid Form can be applied to the material and then be transferred together by temperature treatment in corresponding metal layers. However, should the applied liquid so thin be that the dispersed hard particles are not reliable be held in the corresponding liquid film can be recommended, a completely separate and sequential application.

A corresponding turbine blade can continuously a inventive Protective layer, but for the different Areas of application the protective layer can be adapted. So can for example in the area of the blade ends with the abrasive layer the proportion as well as the size of the hard particles be increased in the hard material layer. Accordingly also such a layer with a lower proportion of solvent be applied. In comparison, the rest Regions are provided with smaller and less hard particles or deposited with a larger proportion of solvent become.

BRIEF DESCRIPTION OF THE FIGURES

Further Advantages, characteristics and features of the present invention in the following detailed description of a Ausführungsbei game clearly with reference to the attached drawings. The painting show here in a purely schematic way in

1 a sectional view through the layer structure of a component according to the invention;

2 a representation of the processing sequence for producing a protective layer according to the invention; and in

3 a perspective view of a turbine blade according to the invention.

EMBODIMENT (E)

1 shows in a partial sectional view of the surface area of a TiAl component 1 wherein the base material can be formed, for example, from γ-TiAl or a corresponding alloy based on γ-TiAl with additions of niobium or accompanying elements such as oxygen, nitrogen, carbon, silicon, hydrogen and the like.

Such components made of titanium aluminides are used due to their light weight, for example in aircraft turbines in the range of low operating temperatures. To protect against erosion, wear and / or corrosion is a two-layer protective layer 4 on the surface of the TiAl material 1 arranged from the sublayers 2 and 3 consists.

The sub-layer 2 is a diffusion barrier layer formed of a noble metal. The noble metals here include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, silver and mercury, in particular palladium, silver, platinum, osmium and gold come into question.

On the diffusion barrier layer 2 a noble metal is a hard material layer 3 provided, which a variety of hard material particles 6 in a precious metal matrix 5 includes. The precious metal matrix 5 may be formed of the same precious metal as the diffusion barrier layer 2 or a different precious metal.

The hard material particles may be formed as nanoparticles, ie have an average or maximum size of 500 nm, in particular 250 nm, preferably 100 nm. Due to the small size of the hard particles, cracking and / or crack growth is suppressed or impeded, which increases the mechanical properties of the protective layer 4 or the entire composite material improved. In addition, the ductile matrix of a precious metal contributes to the fact that no crack formation can take place.

The diffusion barrier layer 2 prevents the diffusion of constituents of the protective layer 4 or in particular the hard material layer 3 and here again of elements of the hard material particles 6 in the TiAl base material, so that an undesirable change in the TiAl base material can be avoided.

The hard material particles may be formed from ceramic materials and in particular one or more components selected from alumina, zirconia, diamond, diamond-like carbon, boron nitride, cubic boron nitride, Ti tannitride, titanium-aluminum nitride or silicon dioxide.

The distribution of the hard material particles 6 in the precious metal matrix 5 in particular with regard to the size of the hard material particles and / or the proportion of the hard material particles 6 in the metal matrix 5 as well as the chemical composition of the hard material particles 6 can vary in the different dimensions of the hard material layer, ie both in the thickness direction perpendicular to the surface of the TiAl material 1 as well as in the independent spatial directions parallel to the surface of the component. For this purpose, for example, the hard material layer can be applied in multiple layers and / or separated according to different areas.

The 2 shows a schematic representation of a production process, with a corresponding protective layer 4 on a TiAl material 1 can be generated. The 2 shows that in a container, a mixture of an organic noble metal compound and a solvent 11 is included, which about brushes or brushes 13 or the like is applied to a TiAl substrate to form a liquid film 12 to form on the surface of the TiAl substrate.

The prepared material is placed in an oven 14 introduced in which a heating device 15 is provided so that the liquid film 12 together with the substrate 10 can be heated. This leads to evaporation of the solvent and to decomposition of the organic noble metal compound and also evaporation of the volatile components, which is schematically represented by the vapor 16 is shown. Back on the TiAl substrate 10 the noble metal component of the organic precious metal compound remains, so that a noble metal layer 20 is formed, the thickness is very small and is in the micrometer range.

Thereafter, the pretreated, provided with a diffusion barrier layer TiAl substrate with a mixture of an organic Edelmetallverbin tion, a solvent and dispersed therein hard material particles are also painted by brush or brush, so that a liquid film 18 on the previously deposited noble metal layer 20 is trained. The thus treated TiAl substrate 10 will be back in the appropriate oven 14 introduced and by means of the heater 15 heated, leaving the solvent of the mixture 17 of organic noble metal compound, solvent and dispersed therein hard material particles evaporated. By the temperature treatment, the organic noble metal compound is decomposed again, wherein the volatile components also evaporate and in the gas phase 16 can be removed by appropriate suction devices (not shown) and disposed of properly.

What remains is a precious metal matrix with embedded hard particles, which are the hard material layer 30 form, so that the total of the protective layer structure of an outer cover layer 30 of hard material particles in a noble metal matrix and a noble metal matrix arranged underneath on the TiAl material.

The application method shown represents only one possibility, and even here modifications and additions are possible. For example, instead of brush or brush application, the mixture 11 or the mixture 17 with other painting technologies, for example spraying or the like. The temperature treatment can be done in other suitable ways.

In addition, it is conceivable that the two different partial layers, namely the diffusion barrier layer 20 and the hard material layer 30 be applied so that first the liquid films 12 and 18 be arranged one above the other and only then the temperature treatment takes place.

The 3 shows a perspective view of a turbine blade 40 to which the present invention can be applied. The turbine blade 40 includes a foot area 41 , which can be used in a corresponding rotor of a gas turbine. In this foot area, it may come to signs of wear, since the turbine blade foot 41 rub against the rotor, which is often made of nickel or a nickel-based alloy. In connection with the present corrosion conditions it can come here to fretting appearances.

The blade 42 For example, erosion may occur in sandy or dusty areas when used in aircraft turbines.

The end area 43 The turbine blade is often subjected to abrasive wear to achieve a good seal against the housing.

All these different conditions, which are to be understood by the generic term wear, can with the above-described protective layer of diffusion barrier 2 and hard material layer 3 be countered. However, the protective layer can 4 according to the fields of application, ie the application in the foot area 41 , in the blade area 42 or the end area 43 be modified accordingly, which, for example, the chemical composition of the hard particles, the Size and distribution and the proportion of hard material particles in the hard material layer as well as the method of application. For example, the end area 43 the turbine blade, which is exposed to high abrasive wear, have a higher concentration of hard material particles, which may be formed in addition to their average particle size or maximum particle size larger than in the remaining area of the. turbine blade 40 , In addition, when applying the layers via an organic noble metal compound with solvents, the solvent concentration can be reduced. Similar adjustments can be made in other areas of the turbine blade 40 make.

Even though the present invention with reference to the accompanying embodiments has been described in detail, is for the expert of course, that the invention is not limited to this Embodiments is limited, so that modifications or changes in the context of the general knowledge Professional are possible, in particular different combinations the featured features as well as omitting individual features, without the scope of the appended claims leave. The present invention includes in particular all Combinations of all featured features.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 3788116 T2 [0005]
• EP 0166676 A2 [0005]
• - CA 2411156 A1 [0005]
• - US 5413871 [0006]
• JP 2003269105 A [0006]
• US 5116430 [0007]
• US 5154816 [0007]
• EP 0456908 A [0022]

Claims (27)

Wear-resistant component for high temperature applications made of a TiAl material with at least a two-layer protective layer ( 4 ), characterized in that a first diffusion barrier layer ( 2 ) of a precious metal and a second layer of hard material ( 3 ) with hard material particles, which are embedded in a noble metal matrix, on the TiAl material ( 1 ) are applied as a protective layer. Component according to claim 1, characterized in that the TiAl material is γ-TiAl, α ₂ -Ti ₃ Al or an alloy based on these intermetallic phases. Component according to one of the preceding claims, characterized in that the diffusion barrier layer ( 2 ) of platinum, palladium, osmium, silver, gold or alloys thereof. Component according to one of the preceding claims, characterized in that the noble metal matrix of the hard material layer ( 3 ) is formed by platinum, osmium, silver, gold or alloys thereof. Component according to one of the preceding claims, characterized in that the hard material particles ( 6 ) of the hard material layer are nanoscale particles. Component according to one of the preceding claims, characterized in that the hard material particles ( 6 ) of the hard material layer have a mean or maximum grain size of 500 nm or less. Component according to one of the preceding claims, characterized in that the hard material particles ( 6 ) of the hard material layer have a mean or maximum grain size of 250 nm or less. Component according to one of the preceding claims, characterized in that the hard material particles of the hard material layer a mean or maximum grain size of 100 nm or less. Component according to one of the preceding claims, characterized in that the hard material particles of the hard material layer made of a ceramic material. Component according to one of the preceding claims, characterized in that the hard material particles of the hard material layer at least one component of the group comprising alumina, Zirconia, diamond, diamond-like carbon, boron nitride, cubic boron nitride (CBN), titanium nitride, titanium-aluminum-nitride, Contains silica and silicon carbide. Component according to one of the preceding claims, characterized in that on the TiAl material exclusively the two-layer protective layer ( 4 ) is arranged. Component according to one of the preceding claims, characterized in that the diffusion barrier layer ( 2 ) is arranged directly on the TiAl material and / or the hard material layer ( 3 ) is formed as a surface layer. Component according to one of the preceding claims, characterized in that the diffusion barrier layer ( 2 ) has a thickness of 0.5 .mu.m to 10 .mu.m and / or the hard material layer has a thickness of 0.1 .mu.m to 100 .mu.m. Component according to one of the preceding claims, characterized in that the hard material particles ( 6 ) over the surface area and / or the thickness of the hard material layer ( 3 ) differ in their size, chemical composition and / or their content in the hard material layer. Process for the preparation of an at least two-layer wear protection layer ( 4 ) on a TiAl material ( 1 ), characterized in that for producing a diffusion barrier layer ( 2 ) a noble metal is deposited and that for forming a hard material layer ( 3 ) are deposited in a noble metal matrix embedded hard material particles. Method according to claim 15, characterized in that a component is produced according to one of claims 1 to 13 becomes. Method according to one of claims 15 to 16, characterized in that for the preparation of the diffusion barrier layer an organic noble metal compound with or without solvent is applied to the TiAl material. Method according to one of claims 15 to 17, characterized in that for the production of the hard material layer an organic noble metal compound with or without solvent is applied with dispersed hard material particles. Method according to one of claims 15 to 18, characterized in that for the preparation of the diffusion barrier layer and / or the hard material layer is an organic noble metal compound is applied with a solvent content of 30% and more. Method according to one of claims 15 to 19, characterized in that the organic Noble metal compound is applied with or without solvent and with or without hard material particles by means of Lakier technique. Method according to one of claims 15 to 20, characterized in that the organic noble metal compound with or without solvent and with or without hard particles subjected to a temperature treatment, so that existing Solvent evaporates and / or the organic noble metal compound is decomposed. Method according to one of claims 15 to 21, characterized in that the organic noble metal compound comprises at least one element from the group comprising Pt, Pd, Os, Re, Ru, Cu, Ag, Au, Ir and Mo contains. Method according to one of claims 15 to 22, characterized in that first the diffusion barrier layer and then the hard material layer are applied. Method according to claim 21, characterized that the temperature treatment for the diffusion barrier layer and / or the hard material layer separately or together he follows. Turbine blade made of a TiAl material with a at least two-ply protective layer, characterized in that a first diffusion barrier layer of a noble metal and a second hard material layer with hard material particles, which are in a precious metal matrix are embedded, covered by the protective layer on the TiAl material are. Turbine blade according to claim 25, characterized in that that as a component according to one of claims 1 to 13 is trained. Turbine blade according to claim 25 or 26, characterized characterized in that in the region of a sealing surface a Hard material layer is provided with an organic noble metal compound with respect to the other protective layer lower Solvent content is applied and / or opposite the remaining protective layer more and / or larger Hard material particle includes.