Metalloceramic materials

Abstract

The invention relates to a powder mixture of ceramic powder and metallic powder, in which the metallic starting powders have a grain size of < 75µm and wherein the oxide-ceramic components are present in a discontinuous manner as a powder with a grain size of 0.2µm - 20µm, wherein no whiskers or fibres are used, wherein at least 10% by weight and a maximum of 70% by weight of ceramic powder is used.

Description

[0001] The invention relates to metalloceramic materials.

[0002] In addition to increasing the combustion temperature, an increase in the efficiency of a gas turbine can also be achieved by reducing the weight of certain components.

[0003] In this area, metallo-ceramic composites, a relatively new class of materials, offer advantages over conventionally used materials. Due to their arbitrarily adjustable composition, the resulting properties, such as weight, wear resistance, strength and ductility, and stresses during operation, can be optimized over a wide range.

[0004] MMC materials are known, in which low-melting materials such as aluminum and magnesium are used.

[0005] It is therefore an object of the invention to improve such materials for high temperatures.

[0006] The problem is solved by a material according to claim 1.

[0007] The subclaims list further advantageous measures which can be combined with one another as desired to achieve further advantages.

[0008] The description only represents embodiments of the invention.

[0009] Due to the variable composition of the metallic and ceramic materials, components for the gas turbine can be designed in such a way that they can be optimized for the upcoming loads.

[0010] Possible application examples include heat shield plates, burner inserts and ring segments, but applications in the cold train, such as compressor blades, are also conceivable.

[0011] A minimum of 10 wt.% and a maximum of 70 wt.% ceramic powder is used, and in particular a minimum of 20 wt.% and a maximum of 60 wt.% ceramic powder is used. The metallic components are selected accordingly.

[0012] The metallo-ceramic materials are produced by mixing and / or granulating ceramic and metal powders in the desired mixing ratios.

[0013] Most of the forming processes used in conventional ceramic manufacturing (e.g. extrusion, casting, pressing, etc.) as well as 3D printing, binder jet printing, etc. can be used to manufacture the components.

[0014] Nickel and / or cobalt-based alloys are preferably used as metallic starting powders, where the metallic starting powders have a grain size of < 75µm, but in particular between 10µm - 60µm. Preferably, these are also metallic powders and alloys that have been developed for purely metallic 3D printing.

[0015] The ceramic components, in particular oxide-ceramic components, are present in a discontinuous manner as a powder with a grain size of 0.2µm - 20µm, but in particular < 15µm. As a rule, no whiskers or fibers are used.

[0016] The ceramic raw materials are synthesized from the melt, by sintering or from solutions and then fractionated.

[0017] Examples of ceramics used are aluminum oxide, magnesium oxide, spinels, zirconates and / or mixtures thereof.

[0018] In contrast to the well-known ODS alloys, in which finely distributed oxides are present at the atomic level, the metalloceramic materials are admixtures at the macroscopic level.

[0019] In contrast to the well-known MMC materials, which use low-melting materials such as aluminum and magnesium, high-melting nickel- or cobalt-based alloys are used here: see figure, IN 738, IN 718, IN 739, IN 939, Rene 80 and / or PWA 1483.

[0020] These alloys, as can be seen in particular from the figure, contain at least nickel, cobalt, chromium, aluminum, titanium and optionally molybdenum, tungsten, tantalum, boron, zirconium and / or niobium,...

[0021] Depending on the application, e.g. in the compressor sector, metallic powders made of steel are also used.

[0022] For applications as bearings for rotors, metallic powder made of bronze is used.

[0023] The forming process is non-melting metallurgical at a temperature < 523K (250°C) with subsequent thermal hardening.

[0024] The process of thermal hardening involves sintering under a protective atmosphere, e.g. argon, possibly accompanied by an additional heat treatment in an oxidizing atmosphere.

[0025] The matrix of a component produced in this way can be metallic, i.e. the metallic content is > 55 vol%.

[0026] The matrix of a component produced in this way can also be ceramic, ie the ceramic content is > 55vol%.

[0027] In the past, the only design options for components were nickel-based metals, possibly with a ceramic coating. These have a weight disadvantage.

[0028] The use of this new class of materials makes it possible, for example, to produce lightweight constructions.

[0029] Furthermore, components can be designed to be optimized with regard to the loads required at the operating point. Example 1:

[0030] IN939 with grain sizes between 20µm - 60µm and a proportion of 65wt% was mixed with aluminum oxide, which has grain sizes of 1.0µm - 15.0µm. Binder jet printing was used for shaping. Subsequently, debinding and sintering took place, preferably in the same furnace. Example 2:

[0031] Rene 80 with grain sizes between 15µm - 45µm and a proportion of 37wt% was mixed with zirconium oxide, which has grain sizes of 0.6µm - 20µm. Binder jet printing was used for shaping. Subsequently, debinding and sintering took place, preferably in the same furnace.

Claims

[1] Powder mixture made of ceramic powder and metallic powder, where the metallic starting powders have a grain size of < 75µm, especially between 10µm - 60µm, and wherein the ceramic components are present in discontinuous distribution as powder, with a grain size of 0.2µm - 20µm, especially < 15µm, in particular, no whiskers or fibres are used, where at least 10 wt.% and a maximum of 70 wt.% ceramic powder, in particular at least 20 wt% and maximum 60 wt% ceramic powder is used. [2] Powder mixture according to claim 1, in which nickel or cobalt-based alloys are used as metallic powders. [3] Powder mixture according to claim 1, in which steels or bronzes are used as metallic powders. [4] Powder mixture according to one or more of claims 1, 2 or 3, in which oxide ceramic powder, in particular aluminum oxide, magnesium oxide, spinels, zirconates or mixtures thereof, is used as the ceramic powder. [5] Powder mixture according to one or more of claims 1, 2, 3 or 4, in which the proportion of the metallic powder is between 90% and 30%. [6] Powder mixture according to one or more of claims 1, 2, 3, 4 or 5, in which the proportion of the ceramic powder is > 55 vol%. [7] Powder mixture according to one or more of claims 1, 2, 3, 4 or 5, in which the proportion of the metallic powder is > 55 vol%. [8] Method for producing a component in which a powder mixture according to one or more of claims 1 to 7 is used. [9] Component, produced from a powder mixture according to one or more of claims 1 to 7 or according to a method according to claim 8.

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