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

Abstract

The invention relates to the technical field of ceramic powder metallurgy, and discloses raw materials and a preparation method of a ceramic core based on a medium-entropy oxide, magnesium oxide, nickel oxide, cobalt monoxide and zinc oxide are adopted as raw materials, and the medium-entropy oxide is synthesized through ball-milling mixing and high-temperature calcination. The medium-entropy oxide with stable entropy is used as a mineralizing agent to be added in preparation of a silicon oxide-based ceramic core, polyvinyl alcohol is added as a plasticizer, the materials are mixed to form ceramic core slurry, a ceramic core biscuit is prepared through compression molding, and the ceramic core biscuit is subjected to powder burying sintering to obtain the ceramic core. The entropy effect, lattice distortion effect and hysteresis diffusion effect of the medium-entropy oxide are utilized to promote the sintering process of the silicon-based ceramic core and control the phase transformation process, so that the room temperature performance and high temperature performance of the silicon oxide-based ceramic core are improved, and the comprehensive performance of the silicon oxide-based ceramic core is enhanced.

Description

Technical Field

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

[0002] Ceramic core is a key component for forming the precise cavity structure inside the casting, especially the hollow blade of the aero-engine. Its comprehensive performance determines the performance and yield of the casting. The ceramic core used in practical applications is mainly prepared by investment casting technology. The entire investment casting process involves the sintering of the core, pressing the wax film, making the shell, removing the wax film and pouring the metal liquid. In the process of pressing the wax film, the room temperature strength of the core is required to be not less than 8MPa to meet the mechanical needs of pressing the wax film. During high-temperature pouring, the core needs to withstand the impact and thermal stress of the high-temperature metal melt, and needs to have sufficient high-temperature bending strength and good creep resistance. The performance of the silicon oxide ceramic core prepared with single-phase quartz glass as raw material can no longer meet the requirements of the ceramic core for hollow blade manufacturing. Therefore, adding mineralizers has become the main means to further enhance the performance of ceramic cores.

[0003] At present, a variety of mineralizers have been introduced into ceramic cores to enhance their comprehensive performance. The most widely used mineralizer is zirconium silicate, which can effectively improve the room temperature and high temperature performance of the core by controlling the precipitation of quartz and the densification process of the core in the silicon oxide ceramic core. At the same time, there are also studies on the addition of single-component mineralizers such as zirconium oxide, aluminum oxide, yttrium oxide, and magnesium oxide to enhance the comprehensive performance of silicon oxide-based ceramic cores. These mineralizers can also play a certain role in improving certain performance. Although these additives have achieved some results in strengthening the core performance, the enhancement effect is still difficult to meet the design and preparation requirements of blades with new hollow structures due to the increasingly high requirements of the current aviation industry system for the inner cavity structure of the engine blade. Therefore, the development and application of new mineralizer systems are of great significance to promoting the development of ceramic cores.

[0004] The existing patent CN113716964A discloses a medium entropy refractory material powder with a core-shell structure, a medium entropy ceramic material with high temperature, ultra-high strength and high toughness, and a preparation method thereof, wherein metal oxide raw materials (TiO2, ZrO2, Ta2 O5) and a carbon source (graphite or carbon black) are uniformly mixed, heated to 1200-1700°C under vacuum conditions, and a (Ti, Zr, Ta) C medium entropy refractory material powder with Zr (Ti, Ta) C as a core and Ti, Ta (Zr) C as a shell is generated by reaction; then, the core-shell structure (Ti, Zr, Ta)-based powder is used as a raw material, and pressure sintered at 1900-2200°C to obtain a (Ti, Zr, Ta) C medium entropy ceramic material having ultra-high strength at high temperature (not less than 1800°C). The technical solution of the present invention prepares a medium entropy ceramic material with an ultra-fine grain size, and at the same time 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 mineralizer, the refractory powder accounts for 65-85% of the 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% of the weight of the silicon-based ceramic core powder, and the silicon nitride powder accounts for 5-30% of the weight of the silicon-based ceramic core powder. The technical solution of the present invention solves the problems of large size shrinkage of 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 for a ceramic core based on a medium entropy oxide, which solves the problem that the single-phase mineralizer component in the prior art is limited in improving the performance of silicon oxide-based ceramic cores.

[0008] To achieve the above-mentioned purpose, the present invention provides a raw material and preparation method for a ceramic core based on a medium entropy oxide. By introducing an entropy-stabilized ceramic phase as a mineralizer, the comprehensive performance of the silicon oxide-based ceramic core can be further improved, and the synergy of the blade manufacturing technology for the core structure and performance requirements can be adapted. The specific technical scheme of the present invention is as follows:

[0009] A raw material for a ceramic core based on a medium entropy oxide, comprising quartz glass powder, a mineralizer and a plasticizer, wherein 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 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 silicon oxide-based ceramic core raw material is 93.8-96.2%, the weight percentage of the mineralizer in the silicon oxide-based ceramic core raw material is 0.8-1.2%, and the weight percentage of the plasticizer in the silicon oxide-based ceramic core raw material 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] Furthermore, 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] Furthermore, the particle size of the quartz glass powder is 10-40 μm.

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

[0015] The present invention also provides a method for preparing a ceramic core based on a medium entropy oxide, wherein the ceramic core is prepared using the raw material of the ceramic core based on the medium entropy oxide, and the preparation method comprises the following steps:

[0016] S1, mixing magnesium oxide powder, nickel oxide powder, cobalt monoxide powder and zinc oxide powder to form a medium entropy oxide;

[0017] 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;

[0018] S3, using silicon oxide-based ceramic core slurry to prepare silicon oxide-based ceramic core blank;

[0019] S4, sintering the silicon oxide-based ceramic core blank powder at high temperature to form a silicon oxide-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, and then dried and calcined at high temperature, and then the powder is ground after high temperature calcination to obtain medium entropy oxide powder with uniform particle size and shape;

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

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

[0023] The ball mill has a rotation speed of 200-350 rpm / min and a milling time of 12-24 hours.

[0024] Furthermore, the step S3 specifically includes: pressing the silicon oxide-based ceramic core slurry to obtain a silicon oxide-based ceramic core blank;

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

[0026] Furthermore, 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.

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

[0028] 1. The present invention provides a raw material and preparation method for a ceramic core based on a 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 for a ceramic core based on a medium-entropy oxide, which utilizes the entropy effect, lattice distortion effect and hysteresis diffusion effect of the medium-entropy oxide to promote the sintering process of the silicon oxide-based ceramic core, control the phase transformation process, and then improve the room temperature and high temperature performance of the silicon oxide-based ceramic core.

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

[0031] 4. The raw materials and preparation method of a ceramic core based on a medium-entropy oxide provided by the present invention have a simple preparation process and can be flexibly designed and customized according to different types of cores or different requirements by utilizing the medium-entropy effect, which greatly expands the selection range of mineralizers. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention.

[0033] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

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

[0035] To achieve the above purpose, the present invention provides a raw material and preparation method for a ceramic core based on a medium entropy oxide, designs a mineralizer through the concept of entropy engineering, synthesizes a medium entropy mineralizer ceramic material, and introduces it into the preparation of a silicon oxide-based ceramic core. The entropy-stabilized ceramic material has a single stable phase structure and has four basic effects, namely, entropy effect, lattice distortion effect, hysteresis diffusion effect, and cocktail effect. Among them, medium entropy ceramics have a large lattice distortion effect, which leads to slow diffusion of atoms inside, and have higher thermal stability than single components. A new mineralizer is prepared through the medium entropy strategy, which can further enhance the room temperature and high temperature performance of the ceramic core.

[0036] The present invention provides a raw material for a ceramic core based on a medium entropy oxide, comprising quartz glass powder, a mineralizer and a plasticizer, wherein the mineralizer is a medium entropy oxide, the plasticizer is polyvinyl alcohol, 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 medium entropy oxide in the silicon oxide-based ceramic core raw material is 0.2%-2%, and the weight percentage of the polyvinyl alcohol in the silicon oxide-based ceramic core raw material is 1-8%.

[0037] The particle size of the quartz glass powder is in the range of 10-40 μm.

[0038] The raw materials of the intermediate entropy oxide include magnesium oxide, nickel oxide, cobalt monoxide and zinc oxide, and the weight percentages of magnesium oxide, nickel oxide, cobalt monoxide and zinc oxide in the intermediate 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 with a particle size range of 0.5-5μm, and the particle size range of the intermediate entropy oxide formed by mixing is 10-30μm.

[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 a medium entropy oxide, wherein the ceramic core is prepared using the raw material of the ceramic core based on the medium entropy oxide, and the method specifically comprises the following steps:

[0041] S1, mixed synthesis of medium entropy oxides;

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

[0043] S2, mixing to form a silicon oxide-based ceramic core raw material;

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

[0045] S3, using silicon oxide-based ceramic core slurry to prepare silicon oxide-based ceramic core blank;

[0046] Specifically, the silicon oxide-based ceramic core slurry is added to a pressing machine, and a ceramic core blank is formed by a pressing method; the pressing machine has a molding pressure of 3-15 MPa and a holding time of 3-10 min.

[0047] S4. The silicon oxide-based ceramic core blank is sintered at high temperature to form a silicon oxide-based ceramic core.

[0048] Specifically, the obtained silicon oxide-based ceramic core blank is placed in a crucible buried with α-alumina powder for high-temperature sintering to finally form a silicon oxide-based ceramic core; the high-temperature sintering temperature is 1100-1300°C, the heating rate is 2-5°C / min, and the insulation time is 1-4h.

[0049] The following describes a medium-entropy oxide reinforced silicon-based ceramic core and a preparation method thereof in combination with specific data.

[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 at a weight percentage 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, the powder mixture is dried in a drying oven. The obtained powder mixture is calcined in a 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 a 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. According to weight percentage, 0.2% of medium entropy oxide powder and 1.8% of polyvinyl alcohol are added to 98% of quartz glass powder for ball milling mixing, the mass fraction of polyvinyl alcohol is 5%, the ball milling speed is 300 rpm / min, the ball milling time is 20h, and the silicon oxide-based ceramic core slurry is obtained by mixing;

[0053] S3, using the silicon oxide-based ceramic core slurry to obtain a silicon oxide-based ceramic core blank by using a pressing machine, the pressing machine has a molding pressure of 10 MPa and a holding time of 5 min;

[0054] S4. Place the obtained silicon oxide-based ceramic core blank into a crucible buried with α-alumina powder for sintering at a heating rate of 2°C / min, a sintering temperature of 1200°C, and a holding time of 3h. Cool the furnace to obtain a medium-entropy oxide-reinforced silicon oxide-based ceramic core.

[0055] The silicon oxide-based ceramic core prepared in this embodiment has a porosity of 30.28%, a flexural strength of 25 MPa at room temperature, and a flexural strength of 48 MPa at high temperature.

[0056] Example 2

[0057] S1. Mix magnesium oxide powder, nickel oxide powder, cobalt oxide powder and zinc oxide powder with a particle size of 2 μm in a ratio of 20%, 30%, 20% and 30%, respectively, at a ball milling speed of 250 rpm / min, and a ball milling time of 10 h. After the ball milling, dry the mixture in a drying oven, and calcine the obtained powder mixture in a resistance furnace at a calcination temperature of 1100 °C, a heating rate of 2 °C / min, and a holding time of 6 h. Grind the calcined medium entropy oxide mineralizer powder and pass it through a 120-mesh sieve to obtain a powder with uniform particle size and shape.

[0058] S2. According to 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 mixing, the mass fraction of polyvinyl alcohol is 3%, the ball milling speed is 300 rpm / min, the ball milling time is 20h, and the silicon oxide-based ceramic core slurry is obtained by mixing;

[0059] S3, using the silicon oxide-based ceramic core slurry to obtain a silicon oxide-based ceramic core blank by using a pressing machine, the pressing machine has a molding pressure of 10 MPa and a holding time of 5 min;

[0060] S4. Sintering the obtained silicon oxide-based ceramic core blank in a crucible buried with α-alumina powder, with a heating rate of 5°C / min, a sintering temperature of 1300°C, and a holding time of 2h. Cooling in the furnace yields a medium-entropy oxide-reinforced silicon oxide-based ceramic core.

[0061] The silicon oxide-based ceramic core prepared in this embodiment has a porosity of 29.58%, a flexural strength of 35 MPa at room temperature, and a flexural strength of 58 MPa at high temperature.

[0062] Example 3

[0063] S1. Mix magnesium oxide powder, nickel oxide powder, cobalt oxide powder and zinc oxide powder with a particle size of 4 μm in a ratio of 10%, 30%, 30% and 30% respectively, with a ball milling speed of 200 rpm / min and a ball milling time of 8 hours. After the ball milling, dry it in a drying oven, and calcine the obtained powder mixture in a resistance furnace at a calcination temperature of 1000 °C, a heating rate of 2 °C / min, and a holding time of 6 hours. Grind the medium entropy oxide mineralizer powder after calcination and pass it through a 120-mesh sieve to obtain a powder with uniform particle size and shape.

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

[0065] S3, using the silicon oxide-based ceramic core slurry to obtain a silicon oxide-based ceramic core blank by a pressing machine, the pressing machine has a molding pressure of 15 MPa and a holding time of 10 min;

[0066] S4. Sinter the obtained silicon oxide-based ceramic core blank in a crucible buried with α-alumina powder, with a heating rate of 3°C / min, a sintering temperature of 1150°C, and a holding time of 4h. Cool the furnace to obtain a medium-entropy oxide-reinforced silicon oxide-based ceramic core.

[0067] The silicon oxide-based ceramic core prepared in this embodiment has a porosity of 35.51%, a flexural strength of 25 MPa at room temperature, and a flexural strength of 53 MPa at high temperature.

[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 in a ratio of 22%, 28%, 21% and 29% by ball milling. The ball milling speed is 250 rpm / min and the ball milling time is 10 hours. After the ball milling, dry it in a drying oven. Calcine the obtained powder mixture in a resistance furnace at a calcination temperature of 1200 °C, a heating rate of 2 °C / min, and a holding time of 6 hours. Grind the medium entropy oxide mineralizer powder after calcination and pass it through a 120-mesh sieve to obtain a powder with uniform particle size and shape.

[0070] S2. According to weight percentage, 1.2% of medium entropy oxide powder and 5% of polyvinyl alcohol are added to 93.8% of quartz glass powder for ball milling mixing, the mass fraction of polyvinyl alcohol is 5%, the ball milling speed is 300 rpm / min, the ball milling time is 20h, and the silicon oxide-based ceramic core slurry is obtained by mixing;

[0071] S3, using the silicon oxide-based ceramic core slurry to obtain a silicon oxide-based ceramic core blank by a pressing machine, the pressing machine has a molding pressure of 10 MPa and a holding time of 5 min;

[0072] S4. Sinter the obtained silicon oxide-based ceramic core blank in a crucible buried with α-alumina powder, with a heating rate of 4°C / min, a sintering temperature of 1200°C, and a holding time of 3h. Cool the furnace to obtain a medium-entropy oxide-reinforced silicon oxide-based ceramic core.

[0073] The silicon oxide-based ceramic core prepared in this embodiment has a porosity of 28.98%, a flexural strength of 39 MPa at room temperature, and a flexural strength of 59 MPa at high temperature.

[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 in a ratio of 24%, 26%, 23% and 27% by ball milling. The ball milling speed is 250 rpm / min and the ball milling time is 10 hours. After the ball milling, dry it in a drying oven. Calcine the obtained powder mixture in a resistance furnace at a calcination temperature of 1200 °C, a heating rate of 2 °C / min, and a holding time of 6 hours. Grind the medium entropy oxide mineralizer powder after calcination and pass it through a 120-mesh sieve to obtain a powder with uniform particle size and shape.

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

[0077] S3, using the silicon oxide-based ceramic core slurry to obtain a silicon oxide-based ceramic core blank by using a pressing machine, the pressing machine has a molding pressure of 10 MPa and a holding time of 5 min;

[0078] S4. Sinter the obtained silicon oxide-based ceramic core blank in a crucible buried with α-alumina powder, with a heating rate of 5°C / min, a sintering temperature of 1300°C, and a holding time of 1h. Cool the furnace to obtain a medium-entropy oxide-reinforced silicon oxide-based ceramic core.

[0079] The silicon oxide-based ceramic core prepared in this embodiment has a porosity of 29.8%, a flexural strength of 26 MPa at room temperature, and a flexural strength of 51 MPa at high temperature.

[0080] Comparative Example 1

[0081] S1. Pure phase quartz glass powder raw material is ball-milled and mixed, 5% by weight of polyvinyl alcohol is added as a plasticizer, the ball milling speed is 300 rpm / min, the ball milling time is 20 h, and the mixture is mixed to form a ceramic core slurry;

[0082] S2, using the ceramic core slurry to obtain a silicon oxide-based ceramic core blank by a pressing machine, the pressing pressure of the pressing machine is 10 MPa, and the holding time is 5 minutes;

[0083] S3. Sintering the obtained ceramic core blank in a crucible buried with α-alumina powder at a sintering temperature of 1200°C, a holding time of 2h, a heating rate of 5°C / min, and obtaining a medium-entropy oxide-reinforced silicon oxide-based ceramic core by cooling in the furnace.

[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 room temperature flexural strength and high temperature flexural strength of the silicon oxide-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 description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0087] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0088] It should be noted that, in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

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 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 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 93.8-96.2%, the weight percentage of the mineralizer in the silicon oxide-based ceramic core raw material is 0.8-1.2%, and the weight percentage of the plasticizer in the silicon oxide-based ceramic core raw material is 3-5%; 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%.

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 S1, magnesium oxide powder, nickel oxide powder, cobalt monoxide powder and zinc oxide powder are ball-milled and mixed according to weight percentage, and then dried and calcined at high temperature, and then ground into powder to obtain medium entropy oxide powder; The ball milling speed is 150-300 rpm / min, the time is 6-12h, the high temperature calcination temperature is 800-1500°C, the time is 2-10h, and the heating rate is 2-10°C / min.

7. 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 a silicon oxide-based ceramic core raw material; The ball mill has a rotation speed of 200-350 rpm / min and a milling time of 12-24 hours.

8. 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 pressure of the compression molding is 3-15 MPa, and the holding time is 3-10 min.

9. 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.