Raw materials and preparation method of a ceramic core based on medium-entropy oxide

Abstract

The present invention relates to the technical field of ceramic powder metallurgy, and discloses a raw material and a preparation method of a ceramic core based on medium-entropy oxides. Magnesium oxide, nickel oxide, cobalt monoxide and zinc oxide are used as raw materials, and medium-entropy oxides are synthesized by ball milling and high-temperature calcination. This entropy-stable medium-entropy oxide is added as a mineralizer to the preparation of silica-based ceramic cores, and polyvinyl alcohol is added as a plasticizer at the same time to form a ceramic core slurry. A ceramic core green body is prepared by pressing molding, and the ceramic core green body is sintered by powder embedding to obtain a ceramic core. The present invention utilizes the entropy effect, lattice distortion effect and retarded diffusion effect of medium-entropy oxides to promote the sintering process of silica-based ceramic cores, control the phase transformation process, and then improve the room-temperature performance and high-temperature performance of silica-based ceramic cores, and strengthen their comprehensive performance.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic powder metallurgy, and particularly relates to a raw material and a preparation method of a ceramic core based on medium-entropy oxides. Background Art

[0002] A ceramic core is a key component for forming a precise cavity structure inside a casting, especially in the hollow blades of an aeroengine. Its comprehensive performance determines the performance and yield of the casting. The actually applied ceramic cores are mainly prepared by investment casting technology. The entire investment casting process involves processes such as sintering of the core, pressing of the wax pattern, manufacturing of the mold shell, removal of the wax pattern, and pouring of molten metal. Among them, during the process of pressing the wax pattern, it is required that the room temperature strength of the core is not lower than 8 MPa to meet the mechanical requirements of pressing the wax pattern. And during high-temperature pouring, the core needs to withstand the impact of high-temperature molten metal and thermal stress, and requires sufficient high-temperature bending strength and good creep resistance. The silica ceramic core prepared with single-phase quartz glass as the raw material can no longer meet the requirements of the hollow blade manufacturing for the ceramic core. Therefore, adding mineralizers has become the main means to further enhance the performance of the ceramic core.

[0003] At present, a variety of mineralizers have been introduced into the ceramic core to enhance its comprehensive performance. The widely used mineralizer is mainly zirconium silicate, which can effectively control the precipitation of cristobalite and the densification process of the core in the silica ceramic core, and improve the room temperature and high-temperature performance of the core. At the same time, in research, single-component mineralizers such as zirconia, alumina, yttria, and magnesia are also added to enhance the comprehensive performance of the silica-based ceramic core, and these mineralizers can also play a certain role in improving some properties. Although these additives have achieved some effects in strengthening the core performance, but in view of the increasingly high requirements for the inner cavity structure of the engine blades in the current development of the aviation industry system, the enhancement effect is still difficult to meet the design and preparation requirements of the blades with a new hollow structure. Therefore, the development and application of a new mineralizer system are of great significance for promoting the development of ceramic cores.

[0004] The existing patent CN113716964A discloses a core-shell structured medium-entropy refractory material powder, a high-temperature ultra-high-strength and high-toughness medium-entropy ceramic material and a preparation method thereof. By uniformly mixing metal oxide raw materials (TiO2, ZrO2, Ta2O5) and a carbon source (graphite or carbon black), heating to 1200-1700 °C under vacuum conditions, a (Ti, Zr, Ta)C medium-entropy refractory material powder with Zr(Ti, Ta)C as the core and Ti, Ta(Zr)C as the shell is generated; then, using the core-shell structured (Ti, Zr, Ta)-based powder as the raw material, pressure sintering is carried out at 1900-2200 °C, and the obtained (Ti, Zr, Ta)C medium-entropy ceramic material has ultra-high strength at high temperature (not lower than 1800 °C). The technical solution of the present invention prepares a medium-entropy ceramic material with an ultrafine grain size and simultaneously improves the high-temperature mechanical properties of the material.

[0005] The existing patent CN114907133A discloses a silicon-based ceramic core material, including silicon-based ceramic core powder. The silicon-based ceramic core powder includes refractory powder and a mineralizer. The refractory powder accounts for 65-85% by weight of the silicon-based ceramic core powder. The mineralizer includes zirconium silicate powder and silicon nitride powder. The zirconium silicate powder accounts for 5-15% by weight of the silicon-based ceramic core powder, and the silicon nitride powder accounts for 5-30% by weight of the silicon-based ceramic core powder. Applying the technical solution of the present invention solves the problems of large size shrinkage of the silicon-based ceramic core, inconsistent shrinkage of thick and thin walls, low high-temperature strength, and large high-temperature deflection.

[0006] In summary, the above two existing patents have not completely solved the problem that the performance of the ceramic core needs to be further improved. Summary of the Invention

[0007] Based on the above technical problems, the present invention provides a raw material and a preparation method of a ceramic core based on medium-entropy oxides, which solves the problem that the single-phase mineralizer component has limitations in improving the performance of silica-based ceramic cores in the prior art.

[0008] To achieve the above object, the present invention provides a raw material and a preparation method of a ceramic core based on medium-entropy oxides. By introducing an entropy-stable ceramic phase as a mineralizer, the comprehensive performance of the silica-based ceramic core can be further improved, and the coordination of the core structure and performance requirements in blade manufacturing technology can be adapted. The specific technical solution of the present invention is as follows:

[0009] A raw material for a ceramic core based on medium-entropy oxide, comprising quartz glass powder, a mineralizer, and a plasticizer. The weight percentage of the quartz glass powder in the raw material of the silica-based ceramic core is 90-98%, the weight percentage of the mineralizer in the raw material of the silica-based ceramic core is 0.2-2%, and the weight percentage of the plasticizer in the raw material of the silica-based ceramic core is 1-8%. The mineralizer is a medium-entropy oxide, and the raw materials of the medium-entropy oxide include magnesium oxide powder, nickel oxide powder, cobalt monoxide powder, and zinc oxide powder.

[0010] The weight percentage of the quartz glass powder in the raw material of the silica-based ceramic core is 93.8-96.2%, the weight percentage of the mineralizer in the raw material of the silica-based ceramic core is 0.8-1.2%, and the weight percentage of the plasticizer in the raw material of the silica-based ceramic core is 3-5%.

[0011] The weight percentages of the magnesium oxide powder, the nickel oxide powder, the cobalt monoxide powder, and the zinc oxide powder in the medium-entropy oxide are all 10-30%.

[0012] Further, the particle sizes of the magnesium oxide powder, the nickel oxide powder, the cobalt monoxide powder, and the zinc oxide powder are all 0.5-5 μm, and the particle size of the medium-entropy oxide is 10-30 μm.

[0013] Further, the particle size of the quartz glass powder is 10-40 μm.

[0014] Further, the plasticizer is polyvinyl alcohol, and the mass fraction of the polyvinyl alcohol is 2-5%.

[0015] The present invention also provides a preparation method for a ceramic core based on medium-entropy oxide, using the raw material of the ceramic core based on medium-entropy oxide to prepare a ceramic core. The preparation method includes the following steps:

[0016] S1. Mix magnesium oxide powder, nickel oxide powder, cobalt monoxide powder, and zinc oxide powder to form a medium-entropy oxide.

[0017] S2. Use quartz glass powder as the raw material, the medium-entropy oxide as the mineralizer, and polyvinyl alcohol as the plasticizer to mix and form a silica-based ceramic core slurry.

[0018] S3. Use the silica-based ceramic core slurry to prepare a silica-based ceramic core green body.

[0019] S4. Burry the silica-based ceramic core green body in powder and sinter it at high temperature to form a silica-based ceramic core.

[0020] Further, in step S1, magnesium oxide powder, nickel oxide powder, cobalt monoxide powder, and zinc oxide powder are ball-milled and mixed according to weight percentage, then dried and subjected to high-temperature calcination, and after high-temperature calcination, powder grinding is carried out to obtain medium-entropy oxide powder with uniform particle size and shape;

[0021] The rotation speed of the ball milling is 150 - 300 rpm / min, and the time is 6 - 12 h. The temperature of the high-temperature calcination is 800 - 1500 °C, the time is 2 - 10 h, and the heating rate is 2 - 10 °C / min.

[0022] Further, in step S2, medium-entropy oxide powder and polyvinyl alcohol are added to quartz glass powder according to weight percentage for ball milling and mixing to obtain silicon oxide-based ceramic core slurry;

[0023] The rotation speed of the ball milling is 200 - 350 rpm / min, and the time is 12 - 24 h.

[0024] Further, step S3 specifically includes: pressing and forming the silicon oxide-based ceramic core slurry to obtain a silicon oxide-based ceramic core green body;

[0025] The pressure of the pressing and forming is 3 - 15 MPa, and the pressure holding time is 3 - 10 min.

[0026] Further, in step S4, the final sintering temperature of the high-temperature sintering is 1100 - 1300 °C, the heating rate is 2 - 5 °C / min, and the heat preservation time is 1 - 4 h.

[0027] Based on the above technical solutions, the present invention has at least the following beneficial effects:

[0028] 1. The present invention provides a raw material and preparation method of a ceramic core based on medium-entropy oxide, synthesizes a new medium-entropy oxide, and introduces it into the preparation and development of silicon oxide-based ceramic cores to enhance the comprehensive performance of silicon oxide-based ceramic cores.

[0029] 2. The present invention provides a raw material and preparation method of a ceramic core based on medium-entropy oxide, utilizes the entropy effect, lattice distortion effect, and retarded diffusion effect of medium-entropy oxide to promote the sintering process of silicon oxide-based ceramic cores, control the phase transformation process, and then improve the room temperature and high-temperature performance of silicon oxide-based ceramic cores.

[0030] 3. The present invention provides a raw material and preparation method of a ceramic core based on medium-entropy oxide, specifically designs the weight percentage of medium-entropy oxide in the raw material of silicon oxide-based ceramic cores, and can well improve the room temperature and high-temperature flexural strength of silicon oxide-based ceramic cores.

[0031] 4. The raw materials and preparation method of a ceramic core based on medium-entropy oxide provided by the present invention have a simple preparation process. Moreover, according to different types of cores or different requirements, flexible design and customization can be carried out by utilizing the medium-entropy effect, greatly expanding the selection range of mineralizers. Detailed Embodiments

[0032] The following further describes the present invention in detail with reference to specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present invention.

[0033] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0034] In order to solve the problem of the limitation of single-phase mineralizer components in improving the performance of silica-based ceramic cores in the prior art, the present invention provides a raw material and a preparation method of a ceramic core based on medium-entropy oxide.

[0035] To achieve the above object, the present invention provides a raw material and a preparation method of a ceramic core based on medium-entropy oxide. By designing the mineralizer through the concept of entropy engineering, a medium-entropy mineralizer ceramic material is synthesized and introduced into the preparation of silica-based ceramic cores. The entropy-stable ceramic material has a single and stable phase structure and has four basic effects, namely, entropy effect, lattice distortion effect, sluggish diffusion effect, and cocktail effect. Among them, due to its large lattice distortion effect, the internal atoms of medium-entropy ceramics diffuse slowly, and it has higher thermal stability than single-component ones. By means of the medium-entropy strategy, a new mineralizer is prepared, which can further strengthen the room-temperature and high-temperature properties of ceramic cores.

[0036] The raw material of a ceramic core based on medium-entropy oxide provided by the present invention includes quartz glass powder, a mineralizer, and a plasticizer. The mineralizer is medium-entropy oxide, and the plasticizer is polyvinyl alcohol. The weight percentage of quartz glass powder in the raw material of the silica-based ceramic core is 90%-98%, the weight percentage of medium-entropy oxide in the raw material of the silica-based ceramic core is 0.2%-2%, and the weight percentage of polyvinyl alcohol in the raw material of the silica-based ceramic core is 1%-8%.

[0037] Among them, the powder particle size range of the quartz glass powder is 10-40 μm.

[0038] The raw materials of the medium-entropy oxide include magnesium oxide, nickel oxide, cobalt monoxide, and zinc oxide. The weight percentages of magnesium oxide, nickel oxide, cobalt monoxide, and zinc oxide in the medium-entropy oxide are 10%-30%, 10%-30%, 10%-30%, and 10%-30% respectively. Magnesium oxide, nickel oxide, cobalt monoxide, and zinc oxide are all powders, and the powder particle size range is 0.5-5 μm. The particle size range of the medium-entropy oxide formed by mixing is 10-30 μm.

[0039] The mass fraction of polyvinyl alcohol is 2 - 5%.

[0040] The present invention also provides a method for preparing a ceramic core based on medium-entropy oxide, using the raw materials of the ceramic core based on medium-entropy oxide described above to prepare the ceramic core, which specifically includes the following steps:

[0041] S1. Mix and synthesize medium-entropy oxide;

[0042] Specifically, weigh magnesium oxide, nickel oxide, cobalt monoxide, and zinc oxide respectively by weight percentage, and synthesize medium-entropy oxide through ball milling and high-temperature calcination; the ball milling speed used during the synthesis process is 150 - 300 rpm / min, the ball milling time is 6 - 12 h, the high-temperature calcination temperature used is 800 - 1500 °C, the sintering time is 2 - 10 h, and the heating rate is 2 - 10 °C / min.

[0043] S2. Mix to form the raw materials of the silica-based ceramic core;

[0044] Specifically, use quartz glass powder as the raw material, medium-entropy oxide as the mineralizer, and polyvinyl alcohol as the plasticizer, and ball mill and mix to form a silica-based ceramic core slurry; the ball milling speed used is 200 - 350 rpm / min, and the ball milling time is 12 - 24 h.

[0045] S3. Use the silica-based ceramic core slurry to prepare a silica-based ceramic core green body;

[0046] Specifically, add the silica-based ceramic core slurry to a molding press, and form a ceramic core green body through a molding method; the molding pressure of the molding press is 3 - 15 MPa, and the pressure holding time is 3 - 10 min.

[0047] S4. The silica-based ceramic core green body is sintered at high temperature to form a silica-based ceramic core.

[0048] Specifically, place the obtained silica-based ceramic core green body in a crucible buried with α-aluminum oxide powder for high-temperature sintering to finally form a silica-based ceramic core; the high-temperature sintering temperature is 1100 - 1300 °C, the heating rate is 2 - 5 °C / min, and the heat preservation time is 1 - 4 h.

[0049] The following combines specific data to illustrate a medium-entropy oxide reinforced silicon-based ceramic core and its preparation method provided by the present invention.

[0050] Example 1

[0051] S1. Mix magnesium oxide powder, nickel oxide powder, cobalt monoxide powder, and zinc oxide powder with a particle size of 3 μm by ball milling according to the weight percentages of 25%, 25%, 25%, and 25% respectively. The ball milling speed is 250 rpm / min, and the ball milling time is 10 h. After the ball milling is completed, perform a drying treatment in a drying oven. Calcinate the obtained powder mixture in an electric resistance furnace at a calcination temperature of 1000 °C, a heating rate of 2 °C / min, and a holding time of 6 h to obtain the synthesized medium-entropy oxide. After grinding the medium-entropy oxide powder, pass it through a 120-mesh sieve to obtain a powder with uniform particle size and shape.

[0052] S2. Add 0.2% of the medium-entropy oxide powder and 1.8% of polyvinyl alcohol by weight percentage to 98% of quartz glass powder for ball milling and mixing. The mass fraction of polyvinyl alcohol is 5%. The ball milling speed is 300 rpm / min, and the ball milling time is 20 h to obtain a silica-based ceramic core slurry.

[0053] S3. Use the silica-based ceramic core slurry to press and form a green body of the silica-based ceramic core by a press molding machine. The molding pressure of the press molding machine is 10 MPa, and the pressure holding time is 5 min.

[0054] S4. Place the obtained green body of the silica-based ceramic core in a crucible buried with α-alumina powder for sintering. The heating rate is 2 °C / min, the sintering temperature is 1200 °C, and the holding time is 3 h. Cool it with the furnace to obtain a silica-based ceramic core reinforced with medium-entropy oxides.

[0055] The porosity of the silica-based ceramic core prepared in this example is 30.28%, the flexural strength at room temperature is 25 MPa, and the flexural strength at high temperature is 48 MPa.

[0056] Example 2

[0057] S1. Mix magnesium oxide powder, nickel oxide powder, cobalt monoxide powder, and zinc oxide powder with a particle size of 2 μm by ball milling according to the ratios of 20%, 30%, 20%, and 30% respectively. The ball milling speed is 250 rpm / min, and the ball milling time is 10 h. After the ball milling is completed, perform a drying treatment in a drying oven. Calcinate the obtained powder mixture in an electric resistance furnace at a calcination temperature of 1100 °C, a heating rate of 2 °C / min, and a holding time of 6 h. After grinding the medium-entropy oxide mineralizer powder after calcination, pass it through a 120-mesh sieve to obtain a powder with uniform particle size and shape.

[0058] S2. According to the weight percentage, 0.8% of medium-entropy oxide powder and 3% of polyvinyl alcohol are added to 96.2% of quartz glass powder for ball milling and mixing. The mass fraction of polyvinyl alcohol is 3%. The ball milling speed is 300 rpm / min, and the ball milling time is 20 h, to obtain a silica-based ceramic core slurry by mixing.

[0059] S3. Using the silica-based ceramic core slurry, a green body of the silica-based ceramic core is obtained by pressing with a press machine. The forming pressure of the press machine is 10 MPa, and the pressure holding time is 5 min.

[0060] S4. The obtained green body of the silica-based ceramic core is sintered in a crucible buried with α-aluminum oxide powder. The heating rate is 5 °C / min, the sintering temperature is 1300 °C, and the heat preservation time is 2 h. Cooling with the furnace gives a silica-based ceramic core reinforced with medium-entropy oxide.

[0061] The porosity of the silica-based ceramic core prepared in this example is 29.58%, the flexural strength at room temperature is 35 MPa, and the flexural strength at high temperature is 58 MPa.

[0062] Example 3

[0063] S1. Magnesium oxide powder, nickel oxide powder, cobalt monoxide powder, and zinc oxide powder with a particle size of 4 μm are ball milled and mixed according to the proportions of 10%, 30%, 30%, and 30% respectively. The ball milling speed is 200 rpm / min, and the ball milling time is 8 h. After ball milling, drying treatment is carried out in a drying oven. The obtained powder mixture is calcined in an electric resistance furnace. The calcination temperature is 1000 °C, the heating rate is 2 °C / min, and the heat preservation time is 6 h. After the calcined medium-entropy oxide mineralizer powder is ground, it is sieved through a 120-mesh sieve to obtain a powder with uniform particle size and shape.

[0064] S2. According to the weight percentage, 2% of medium-entropy oxide powder and 8% of polyvinyl alcohol are added to 90% of quartz glass powder for ball milling and mixing. The mass fraction of polyvinyl alcohol is 5%. The ball milling speed is 300 rpm / min, and the ball milling time is 20 h, to obtain a silica-based ceramic core slurry by mixing.

[0065] S3. Using the silica-based ceramic core slurry, a green body of the silica-based ceramic core is obtained by pressing with a press machine. The forming pressure of the press machine is 15 MPa, and the pressure holding time is 10 min.

[0066] S4. The obtained green body of the silica-based ceramic core is sintered in a crucible buried with α-aluminum oxide powder. The heating rate is 3 °C / min, the sintering temperature is 1150 °C, and the heat preservation time is 4 h. Cooling with the furnace gives a silica-based ceramic core reinforced with medium-entropy oxide.

[0067] The porosity of the silica-based ceramic core prepared in this example is 35.51%, the flexural strength at room temperature is 25 MPa, and the flexural strength at high temperature is 53 MPa.

[0068] Example 4

[0069] S1. Mix magnesium oxide powder, nickel oxide powder, cobalt monoxide powder and zinc oxide powder with a particle size of 1 μm by ball milling according to the proportions of 22%, 28%, 21% and 29%. The ball milling speed is 250 rpm / min and the ball milling time is 10 h. After ball milling, perform a drying treatment in a drying oven. Calcinate the obtained powder mixture in an electric resistance furnace at a calcination temperature of 1200 °C, a heating rate of 2 °C / min, and a holding time of 6 h. After grinding the calcined medium-entropy oxide mineralizer powder, pass it through a 120-mesh sieve to obtain a powder with uniform particle size and shape.

[0070] S2. Add 1.2% of the medium-entropy oxide powder and 5% of polyvinyl alcohol by weight to 93.8% of quartz glass powder for ball milling and mixing. The mass fraction of polyvinyl alcohol is 5%. The ball milling speed is 300 rpm / min and the ball milling time is 20 h to obtain a silica-based ceramic core slurry.

[0071] S3. Use the silica-based ceramic core slurry to press and form a green body of the silica-based ceramic core with a molding pressure of 10 MPa and a pressure holding time of 5 min by a pressing machine.

[0072] S4. Sinter the obtained green body of the silica-based ceramic core in a crucible buried with α-aluminum oxide powder at a heating rate of 4 °C / min, a sintering temperature of 1200 °C, and a holding time of 3 h, and then cool it with the furnace to obtain a medium-entropy oxide-reinforced silica-based ceramic core.

[0073] The porosity of the silica-based ceramic core prepared in this example is 28.98%, the flexural strength at room temperature is 39 MPa, and the flexural strength at high temperature is 59 MPa.

[0074] Example 5

[0075] S1. Mix magnesium oxide powder, nickel oxide powder, cobalt monoxide powder and zinc oxide powder with a particle size of 1 μm by ball milling according to the proportions of 24%, 26%, 23% and 27%. The ball milling speed is 250 rpm / min and the ball milling time is 10 h. After ball milling, perform a drying treatment in a drying oven. Calcinate the obtained powder mixture in an electric resistance furnace at a calcination temperature of 1200 °C, a heating rate of 2 °C / min, and a holding time of 6 h. After grinding the calcined medium-entropy oxide mineralizer powder, pass it through a 120-mesh sieve to obtain a powder with uniform particle size and shape.

[0076] S2. According to the weight percentage, 2% of medium-entropy oxide powder and 1% of polyvinyl alcohol are added to 97% of quartz glass powder for ball milling and mixing. The mass fraction of polyvinyl alcohol is 5%, the ball milling speed is 300 rpm / min, and the ball milling time is 20 h to obtain a silica-based ceramic core slurry by mixing.

[0077] S3. Use the silica-based ceramic core slurry to press and form a green body of the silica-based ceramic core by a pressing machine. The forming pressure of the pressing machine is 10 MPa, and the pressure holding time is 5 min.

[0078] S4. Sinter the obtained green body of the silica-based ceramic core in a crucible buried with α-aluminum oxide powder. The heating rate is 5 °C / min, the sintering temperature is 1300 °C, and the heat preservation time is 1 h. Then, it is cooled with the furnace to obtain a silica-based ceramic core reinforced by medium-entropy oxides.

[0079] The porosity of the silica-based ceramic core prepared in this example is 29.8%, the flexural strength at room temperature is 26 MPa, and the flexural strength at high temperature is 51 MPa.

[0080] Comparative Example 1

[0081] S1. Use pure-phase quartz glass powder as the raw material for ball milling and mixing, and add polyvinyl alcohol with a weight fraction of 5% as a plasticizer. The ball milling speed is 300 rpm / min, and the ball milling time is 20 h to form a ceramic core slurry by mixing.

[0082] S2. Use the ceramic core slurry to press and form a green body of the silica-based ceramic core by a pressing machine. The forming pressure of the pressing machine is 10 MPa, and the pressure holding time is 5 min.

[0083] S3. Sinter the obtained green body of the ceramic core in a crucible buried with α-aluminum oxide powder. The sintering temperature is 1200 °C, the heat preservation time is 2 h, the heating rate is 5 °C / min, and it is cooled with the furnace to obtain a silica-based ceramic core reinforced by medium-entropy oxides.

[0084] The porosity of the ceramic core prepared in this comparative example is 30.87%, the flexural strength at room temperature is 22 MPa, and the flexural strength at high temperature is 28 MPa.

[0085] By comparing the above Examples 1-4 and the comparative example, it is found that the introduction of the medium-entropy oxide mineralizer significantly enhances the flexural strength at room temperature and high temperature of the silica-based ceramic core, indicating that the synthesized medium-entropy oxide mineralizer plays an important role in enhancing the performance of the ceramic core.

[0086] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0087] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0088] It should be noted that in the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

Claims

1. A raw material for a ceramic core based on a medium entropy oxide, comprising quartz glass powder, a mineralizer and a plasticizer, characterized in that: The mineralizer is a medium entropy oxide, and the raw materials of the medium entropy oxide include magnesium oxide powder, nickel oxide powder, cobalt monoxide powder and zinc oxide powder; the weight percentage of the quartz glass powder in the silicon oxide-based ceramic core raw material is 90-98%, the weight percentage of the mineralizer in the silicon oxide-based ceramic core raw material is 0.2-2%, and the weight percentage of the plasticizer in the silicon oxide-based ceramic core raw material is 1-8%; The weight percentage of the magnesium oxide powder, the nickel oxide powder, the cobalt monoxide powder and the zinc oxide powder in the medium entropy oxide is 10-30%; The magnesium oxide powder, the nickel oxide powder, the cobalt monoxide powder and the zinc oxide powder are ball-milled and mixed, and then dried and high-temperature calcined. After high-temperature calcination, the powder is ground to obtain medium-entropy oxide powder; the rotation speed of the ball mill is 150-300rpm / min, the time is 6-12h, the temperature of the high-temperature calcination is 800-1500°C, the time is 2-10h, and the heating rate is 2-10°C / min.

2. The raw material for the ceramic core based on the medium entropy oxide according to claim 1, characterized in that: The particle sizes of the magnesium oxide powder, the nickel oxide powder, the cobalt monoxide powder and the zinc oxide powder are all 0.5-5 μm, and the particle size of the medium entropy oxide is 10-30 μm.

3. The raw material for the ceramic core based on the medium entropy oxide according to claim 1, characterized in that: The particle size of the quartz glass powder is 10-40 μm.

4. The raw material for the ceramic core based on the medium entropy oxide according to claim 1, characterized in that: The plasticizer is polyvinyl alcohol, and the mass fraction of the polyvinyl alcohol is 2-5%.

5. A method for preparing a ceramic core based on a medium entropy oxide, using the raw material of the ceramic core based on a medium entropy oxide as described in any one of claims 1 to 4 to prepare the ceramic core, characterized in that: The preparation method comprises the following steps: S1, mixing magnesium oxide powder, nickel oxide powder, cobalt monoxide powder and zinc oxide powder to form a medium entropy oxide; S2, using quartz glass powder as raw material, medium entropy oxide as mineralizer, polyvinyl alcohol as plasticizer to mix and form silicon oxide-based ceramic core slurry; S3, using silicon oxide-based ceramic core slurry to prepare silicon oxide-based ceramic core blank; S4, sintering the silicon oxide-based ceramic core blank powder at high temperature to form a silicon oxide-based ceramic core.

6. The method for preparing a ceramic core based on a medium entropy oxide according to claim 5, characterized in that: In step S2, medium entropy oxide powder and polyvinyl alcohol are added to quartz glass powder according to weight percentage and ball-milled to obtain silicon oxide-based ceramic core raw material; the ball milling speed is 200-350 rpm / min and the time is 12-24h.

7. The method for preparing a ceramic core based on a medium entropy oxide according to claim 5, characterized in that: In step S3, the silicon oxide-based ceramic core slurry is pressed and molded to obtain a silicon oxide-based ceramic core blank; the pressing pressure is 3-15 MPa, and the holding time is 3-10 min.

8. The method for preparing a ceramic core based on a medium entropy oxide according to claim 5, characterized in that: In step S4, the final sintering temperature of the high temperature sintering is 1100-1300°C, the heating rate is 2-5°C / min, and the holding time is 1-4h.