A refractory metal-ceramic composite environmental barrier coating bond coat material

Abstract

The application discloses a refractory metal-ceramic composite environmental barrier coating adhesive layer material, which is prepared by uniformly mixing HfO2 and Nb through mechanical crushing, and in the adhesive layer material, the mass percentage of HfO2 is 60% to 90%, and the mass percentage of elemental Nb is 10% to 40%. The novel composite environmental barrier adhesive layer material has simple raw material composition, good uniformity, high use temperature and effectively improves the service life of the environmental barrier coating.

Description

Technical Field

[0001] This invention relates to the field of ceramic coating material preparation technology, specifically to a refractory metal-ceramic composite environmental barrier coating adhesive layer material and its preparation method. Background Technology

[0002] In recent years, with the continuous development of the aerospace industry, the gas temperature in gas turbines has reached 1500-1700℃, and ceramic matrix composites (CMCs) have replaced nickel-based superalloys as a new type of high-temperature structural material. Meanwhile, the long-term service temperature of hot-end components has exceeded 1400℃, necessitating the application of environmental barrier coatings (EBCs) for protection. To enhance the adhesion between EBCs and the substrate and reduce thermal expansion mismatch between the substrate and the EBC, an adhesive layer must be used between the EBC and the ceramic matrix composite. Therefore, the adhesive layer materials for EBCs and their preparation methods have become one of the research hotspots in high-temperature thermal protection materials.

[0003] Existing environmental barrier coating adhesive materials are mainly pure Si adhesive layers and Si-containing composite adhesive layers, such as Si-HfO2 series materials and Yb-Gd-Si ternary alloy series materials. By rationally selecting components and proportions, adhesive materials with matching coefficients of thermal expansion can be obtained.

[0004] As engine operating temperatures increase, the turbine inlet temperature will exceed the melting point of Si. Operating temperatures exceeding the melting point of Si will cause Si to penetrate into the substrate, causing the adhesive layer to disappear and the coating to fail, which is detrimental to protecting the substrate. Summary of the Invention

[0005] Based on the shortcomings of the prior art, the technical problem solved by the present invention is to provide an environmental barrier coating adhesive layer material that is free of Si, has a coefficient of thermal expansion that matches the substrate, and can be used at temperatures exceeding 1400°C.

[0006] To address the aforementioned technical problems, this invention provides a method for preparing a novel refractory metal-ceramic composite bulk material, characterized by comprising the following steps:

[0007] (1) HfO2 and metallic Nb are dried and mixed, and then ball-milled to obtain a uniform slurry. The slurry is then fed into a spray granulation tower for spray drying to obtain a mixed powder.

[0008] (2) The mixed powder is placed in a plasma sintering furnace and rapidly sintered to obtain a composite block.

[0009] As a preferred embodiment of the above technical solution, the novel refractory metal-ceramic composite bulk material provided by the present invention further includes some or all of the following technical features:

[0010] As an improvement to the above technical solution, the HfO2 content is 60% to 90% by mass percentage, and the metallic Nb content is 10% to 40%.

[0011] As a preferred embodiment of the above technical solution, the sintering temperature is 1300-1500℃ and the holding pressure is 40 MPa.

[0012] The present invention also includes a method for preparing a refractory metal-ceramic composite environmental barrier coating adhesive layer material, comprising the following steps:

[0013] (1) Add deionized water and binder to the mixed powder, mix and then ball mill it. Then pass the slurry into a spray granulation tower for spray granulation and sieve to obtain spherical powder.

[0014] (2) The sieved spherical powder is sprayed onto the surface of pretreated SiC ceramic sheets, SiC / SiCf composite materials and other substrates using plasma spraying technology to obtain a coating with high melting point.

[0015] As a preferred embodiment of the above technical solution, the particle size of the spherical powder after sieving is 32-125 μm.

[0016] The present invention also provides a novel composite environmental barrier adhesive layer material of refractory metal-ceramic that is free of Si and has a high melting point. The novel composite environmental barrier adhesive layer material of refractory metal-ceramic is formed by mechanically crushing and mixing two base materials; the base materials include HfO2 and metallic Nb.

[0017] As a preferred embodiment of the above technical solution, the HfO2 comprises 60% to 90% by mass percentage, and the metallic Nb comprises 10% to 40%.

[0018] As a preferred embodiment of the above technical solution, the novel composite environmental barrier adhesive layer material containing Si and having a high melting point of refractory metal-ceramic is prepared by any of the above methods.

[0019] As a preferred embodiment of the above technical solution, the novel composite environmental barrier adhesive layer material of refractory metal-ceramic that does not contain Si and has a high melting point, as described above, has a melting point of 2758℃ for HfO2 and 2477℃ for Nb. The melting point of the mixture after doping the two is generally between these two. Therefore, the novel composite environmental barrier adhesive layer material of refractory metal-ceramic can be used at a temperature ≥1400℃.

[0020] The present invention also claims the application of a novel Si-free, high-melting-point refractory metal-ceramic composite environmental barrier bonding layer material, wherein the Si-free, high-melting-point refractory metal-ceramic composite environmental barrier bonding layer material is used as a coating for thermal protection of aerospace components.

[0021] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0022] (1) The raw material composition of the novel refractory metal-ceramic composite environmental barrier bonding layer material of the present invention is simple and the preparation method is simple and easy to control. It is made by mixing HfO2 and Nb in a certain proportion.

[0023] (2) This invention utilizes two high-melting-point materials to form a novel refractory metal-ceramic composite environmental barrier bonding layer, which can effectively improve the service temperature of the environmental barrier coating. Its coating is widely used in the thermal protection of aerospace components.

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, the following detailed description is provided in conjunction with preferred embodiments. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0026] Figure 1 This is a structural diagram of the adhesive layer of the refractory metal-ceramic composite environmental barrier coating material of the present invention.

[0027] Figure 2 The curves show the coefficient of thermal expansion of the HfO2-Nb coating prepared in Example 1 and the bulk materials prepared in Examples 4 and 5, within a temperature range of 200-1400℃. Detailed Implementation

[0028] The following detailed description of specific embodiments of the present invention is part of this specification. The principles of the present invention are illustrated through examples, and other aspects, features and advantages of the present invention will become apparent from this detailed description.

[0029] The technical solution of the present invention is as follows:

[0030] A refractory metal-ceramic composite environmental barrier coating adhesive material, the material composition comprising elemental Nb and HfO2; by mass percentage, the HfO2 is 60%–90% and the elemental Nb is 10%–40%.

[0031] A second objective of this invention is to provide a method for preparing a refractory metal-ceramic composite bulk product, the method comprising the following steps:

[0032] (1) The material powder is mixed in a certain proportion and ball-milled for 72 hours to obtain a uniformly mixed slurry. The slurry is then spray-granulated through a spray granulation tower and sieved to obtain a mixed powder.

[0033] (2) The composite block product is obtained by rapid sintering in a plasma sintering furnace at a sintering temperature of 1350℃ and a holding pressure of 40MPa.

[0034] A third objective of this invention is to provide a method for preparing a refractory metal-ceramic composite environmental barrier bonding coating material, the method comprising the following steps:

[0035] (1) The refractory metal-ceramic composite powder is added to deionized water, binder and other materials in proportion, and then ball milled, spray granulated and sieved to obtain composite powder material.

[0036] (2) The spherical composite powder prepared above was sprayed onto the pretreated SiC ceramic sheet and SiC / SiC using plasma spraying technology. f A novel refractory metal-ceramic composite environmental barrier bonding layer is prepared on the surface of composite materials and other matrices.

[0037] Example 1

[0038] A novel refractory metal-ceramic composite environmental barrier adhesive layer is provided, which is composed of 90 wt.% HfO2 and 10 wt% elemental Nb.

[0039] The above adhesive layer preparation process is as follows:

[0040] (1) Take the above proportion of mixed powder, add a certain amount of deionized water, zirconium balls and an appropriate amount of binder to the ball mill jar, and then place the ball mill jar on a ball mill with a rotation speed of 36 r / min for 72 h.

[0041] (2) Filter the ball-milled slurry through a 200-mesh screen and pass it into a spray granulation tower for granulation. The parameters of the spray granulation tower are set as follows: inlet temperature is 220℃, outlet temperature is 110℃, and atomizer frequency is 22Hz.

[0042] (3) The dried powder after granulation is sieved to obtain a binder layer powder of 32-125μm.

[0043] Tests showed that, within a temperature range of 200-1400℃, the average coefficient of thermal expansion of the novel refractory metal-ceramic composite environmental barrier adhesive layer of this embodiment was 6.48 × 10⁻⁶. -6 K -1 .

[0044] Example 2

[0045] A novel refractory metal-ceramic composite environmental barrier adhesive layer is provided, which is composed of 80 wt.% HfO2 and 20 wt% elemental Nb.

[0046] The above adhesive layer preparation process is as follows:

[0047] (1) Take the above proportion of mixed powder, add a certain amount of deionized water, zirconium balls and an appropriate amount of binder to the ball mill jar, and then place the ball mill jar on a ball mill with a rotation speed of 36 r / min for 72 h.

[0048] (2) Filter the ball-milled slurry through a 200-mesh screen and pass it into a spray granulation tower for granulation. The parameters of the spray granulation tower are set as follows: inlet temperature is 220℃, outlet temperature is 110℃, and atomizer frequency is 22Hz.

[0049] (3) The dried powder after granulation is sieved to obtain a binder layer powder of 32-125μm.

[0050] Example 3

[0051] A novel refractory metal-ceramic composite environmental barrier adhesive layer is provided, which is composed of 70 wt.% HfO2 and 30 wt% elemental Nb.

[0052] The above adhesive layer preparation process is as follows:

[0053] (1) Take the above proportion of mixed powder, add a certain amount of deionized water, zirconium balls and an appropriate amount of binder to the ball mill jar, and then place the ball mill jar on a ball mill with a rotation speed of 36 r / min for 72 h.

[0054] (2) Filter the ball-milled slurry through a 200-mesh screen and pass it into a spray granulation tower for granulation. The parameters of the spray granulation tower are set as follows: inlet temperature is 220℃, outlet temperature is 110℃, and atomizer frequency is 22Hz.

[0055] (3) The dried powder after granulation is sieved to obtain a binder layer powder of 32-125μm.

[0056] Example 4

[0057] A novel refractory metal-ceramic composite bulk material is disclosed, comprising 70% HfO2 and 30% metallic Nb.

[0058] The above-mentioned bulk material preparation process is as follows:

[0059] The above raw materials were mixed in different mass percentages, then ball-milled for 72 hours, dried, and ground to obtain a mixed powder. Nb-HfO2 ceramic bulk materials were then prepared by spark plasma sintering. The spark plasma sintering experimental parameters were as follows: room temperature - 600℃, heating rate 150℃, pressure 40MPa; 600-1200℃, heating rate 100℃, pressure 40MPa; 1200-1400℃, heating rate 50℃, pressure 40MPa.

[0060] Tests showed that, within a temperature range of 200-1400℃, the average coefficient of thermal expansion of the novel refractory metal-ceramic composite bulk material of this embodiment was 7.40 × 10⁻⁶. -6 K -1 .

[0061] Example 5

[0062] A novel refractory metal-ceramic composite bulk material is disclosed, comprising 80% HfO2 and 20% metallic Nb.

[0063] The above-mentioned bulk material preparation process is as follows:

[0064] The above raw materials were mixed in different mass percentages, then ball-milled for 72 hours, dried, and ground to obtain a mixed powder. Nb-HfO2 ceramic bulk materials were then prepared by spark plasma sintering. The spark plasma sintering experimental parameters were as follows: room temperature - 600℃, heating rate 150℃, pressure 40MPa; 600-1200℃, heating rate 100℃, pressure 40MPa; 1200-1400℃, heating rate 50℃, pressure 40MPa.

[0065] Tests showed that, within a temperature range of 200-1400℃, the average coefficient of thermal expansion of the novel refractory metal-ceramic composite bulk material of this embodiment was 6.94 × 10⁻⁶. -6 K -1 .

[0066] All the raw materials listed in this invention, as well as the upper and lower limits and ranges of the raw materials and the upper and lower limits and ranges of the process parameters (such as temperature, time, etc.), can realize this invention. Examples are not listed one by one here.

[0067] The above description is merely a preferred embodiment of the present invention, and should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A refractory metal-ceramic composite environmental barrier coating adhesive layer material, characterized in that: The adhesive layer material is formed by mechanically crushing and mixing raw materials including HfO2 and elemental Nb, granulating them, and then spraying them onto the substrate surface using plasma spraying technology. By mass percentage, the raw materials contain 60%–90% HfO2 and 10%–40% elemental Nb. The adhesive layer material is Si-free and is applied to SiC ceramics or SiC / SiC ceramics. x It serves as an adhesive layer in environmental barrier coatings for composite material matrices.

2. The refractory metal-ceramic composite environmental barrier coating adhesive layer material according to claim 1, characterized in that: The raw materials contain 70% to 80% HfO2 and 20% to 30% elemental Nb.

3. The refractory metal-ceramic composite environmental barrier coating adhesive layer material according to claim 1, characterized in that: The adhesive layer material has a service temperature ≥1400℃.

4. A method for preparing spherical powder of the refractory metal-ceramic composite environmental barrier coating binder material according to any one of claims 1-3, characterized in that, The process includes the following steps: (1) HfO2 and elemental Nb are dried and mixed, and after ball milling, a uniform slurry is obtained. The slurry is then fed into a spray granulation tower for spray drying to obtain a mixed powder; (2) The mixed powder is placed in a discharge plasma sintering furnace and rapidly sintered at a sintering temperature of 1300~1500℃ and a holding pressure of 40MPa to obtain a composite synthetic block.

5. A method for preparing the refractory metal-ceramic composite environmental barrier coating adhesive layer material according to any one of claims 1-3, characterized in that, The steps include: (1) adding deionized water and binder to the mixed powder of HfO2 and elemental Nb to form a slurry, then ball milling, and then passing the slurry into a spray granulation tower for spray granulation. After sieving, spherical powder with a particle size of 32~125μm is obtained; by mass percentage, the HfO2 is 60%~90% and the elemental Nb is 10%~40%; (2) using plasma spraying technology to spray the sieved spherical powder onto pretreated SiC ceramic sheets or SiC / SiC ceramic sheets. x The adhesive layer material is obtained on the surface of the composite matrix.

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