Highly yielding silicon-based ceramic core for nickel-based single crystal blades and preparation method thereof

Abstract

The invention discloses a high-yield silicon-based ceramic core for nickel-based single crystal blades and a preparation method thereof. The mass percentage of each substance in the silicon-based ceramic core is 20-65wt% of core-shell structure quartz glass powder, 30-75wt% of fused quartz glass powder, 3-35wt% of mineralizer, and 1-10wt% of special additive. The preparation method comprises the following steps: preparing core-shell structure quartz glass powder, mineralizer, and special additive of each particle size; mixing each substance evenly to obtain silicon-based ceramic powder, and mixing it evenly with a plasticizer to obtain silicon-based ceramic core slurry; filling and pressing to obtain a silicon-based ceramic core blank, and a high-yield silicon-based ceramic core can be obtained after roasting. The present invention realizes that the silicon-based ceramic core has excellent shrinkage concession, strength concession, creep concession and other characteristics during the solidification process of high-temperature alloy liquid, and effectively solves the problem of recrystallization in the inner cavity of nickel-based single crystal high-temperature alloy blades.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic core material design and preparation, and specifically relates to a high-yield silicon-based ceramic core for nickel-based single crystal blades and a preparation method thereof. Background Art

[0002] At present, the complexity of the air-cooled structure and the large-scale size of single-crystal high-temperature alloy hollow turbine blades have become an effective means and an inevitable trend to continue to improve the overall performance of key hot-end components of aircraft engines. With the complexity and large-scale size of advanced turbine blades, the ceramic core structure that forms its inner cavity structure has also become more complex.

[0003] During the casting process of single-crystal hollow turbine blades, residual stress is generated at the characteristic structure of the blade cavity because the alloy liquid is hindered by the complex structure of the ceramic core during directional solidification. The residual stress is released and recrystallized during the subsequent heat treatment. Since single-crystal high-temperature alloys reduce grain boundary strengthening elements, once any grain boundary and recrystallized grains perpendicular to the stress principal axis are generated, they will become weak areas of single-crystal high-temperature alloy components, forming crack sources during service in high-temperature environments, which will seriously reduce the durability and fatigue life of turbine blades, and thus affect the service life of aircraft engines.

[0004] During the development of single crystal blades, it was found that the probability of blade failure due to non-continuous structures such as surface plastic recrystallization and surface structural recrystallization on the surface reached more than 30%, which has become a barrier to the development of a new generation of aircraft engines. Therefore, in order to give full play to the potential of the mechanical properties of single crystal high-temperature alloy materials and at the same time ensure the integrity of the complex structure of single crystal blades and the continuity of material organization, it is urgent to carry out research on effective control technology for recrystallization in the blade cavity.

[0005] The high-temperature performance of the ceramic core includes high-temperature creep rate, elastic modulus, high-temperature bending strength, thermal expansion, high-temperature shrinkage, etc., which are closely related to the performance matching between the ceramic core and the metal, and also directly affect the recrystallization behavior of the blade cavity. These properties together constitute the high-temperature concession performance of the ceramic core, which includes shrinkage concession, strength concession and creep concession. If the high-temperature concession of the ceramic core is low, then during the solidification and shrinkage of the alloy liquid, it is very easy to generate internal stress in the blade cavity, which in turn causes recrystallization in the blade cavity; if the high-temperature concession of the ceramic core is high, then the excellent matching of the high-temperature performance of the ceramic core and the alloy liquid can be achieved, which can effectively alleviate the problem of recrystallization in the single crystal blade cavity. Therefore, it is urgent to develop a high-concession silicon-based ceramic core for nickel-based single crystal blades and a preparation method thereof to minimize the recrystallization of the single crystal blade cavity during the solidification process. The invention patent with application publication number CN109304424A discloses a modified silicon oxide powder and its preparation method, a ceramic core and its preparation method. The modified silicon oxide powder is a core-shell type high temperature resistant oxide coated silicon oxide powder structure, and the high temperature resistant oxide is one or more of aluminum oxide, yttrium oxide, and zirconium oxide. The preparation of the modified silicon oxide powder includes the following steps: adding silicon oxide powder particles to a high temperature resistant metal oxide sol and stirring the reaction to obtain silicon oxide powder particles after a sol bath; drying the silicon oxide powder particles after the sol bath, placing them in a ball mill for ball milling to obtain modified silicon oxide powder after one ball milling; adding the modified silicon oxide powder after one ball milling to a high temperature resistant metal oxide sol, repeating the above steps 2-3 times, and obtaining modified silicon oxide powder. Due to the coating of the sol in the modified silicon oxide powder, this technical solution enables the silicon-based ceramic core to have better high temperature resistance, but it cannot achieve the effect of improving the yieldability of the silicon-based ceramic core to avoid recrystallization in the blade cavity. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a high-yield silicon-based ceramic core for a nickel-based single crystal blade, wherein the mass percentage of each substance in the silicon-based ceramic core is 20-65wt% of core-shell structure quartz glass powder, 30-75wt% of fused quartz glass powder, 3-35wt% of mineralizer, and 1-10wt% of special additive, and the sum of the contents of each substance is 100wt%.

[0007] Preferably, the mass percentage of each substance in the core-shell structure quartz glass powder to the core-shell structure quartz glass powder is 30-55wt% of fused quartz glass powder, 20-45wt% of sol, and 25-50wt% of cristobalite, and the sum of the contents of each substance is 100wt%.

[0008] In any of the above schemes, preferably, the core-shell structure quartz glass powder includes six particle sizes, namely 75-150μm, 48-75μm, 38-48μm, 25-38μm, 20-25μm, and 0-20μm; the mass percentage of each particle size in the core-shell structure quartz glass powder is 10-25wt% for particle size 75-150μm, 10-25wt% for particle size 48-75μm, 20-35wt% for particle size 38-48μm, 10-25wt% for particle size 25-38μm, 5-15wt% for particle size 20-25μm, and 5-10wt% for particle size 0-20μm, and the sum of the contents of materials in each particle size is 100wt%.

[0009] In any of the above schemes, preferably, the fused silica glass powder in the core-shell structured quartz glass powder includes four particle sizes, namely 48-65 μm, 35-48 μm, 20-35 μm, and 5-20 μm; the mass percentage of each particle size in the fused silica glass powder is 30-50wt% for a particle size of 48-65 μm, 20-30wt% for a particle size of 35-48 μm, 20-30wt% for a particle size of 20-35 μm, and 5-10wt% for a particle size of 5-20 μm, and the sum of the contents of materials in each particle size is 100wt%.

[0010] In any of the above schemes, it is preferred that the sol includes any one or more of silica sol, aluminum sol, yttrium sol, zirconium sol and magnesium sol; and the cristobalite includes a particle size range of 1-10 μm.

[0011] In any of the above schemes, preferably, the fused quartz glass powder in the silicon-based ceramic core includes four particle sizes, namely 35-62 μm, 18-35 μm, 5-18 μm, and 0.5-5 μm; the mass percentage of each particle size in the quartz glass powder is 35-48wt% for a particle size of 35-62 μm, 18-25wt% for a particle size of 18-35 μm, 22-35wt% for a particle size of 5-18 μm, and 5-10wt% for a particle size of 0.5-5 μm, and the sum of the contents of materials in each particle size is 100wt%.

[0012] In any of the above schemes, it is preferred that the mass percentage of each substance in the mineralizer is 22-30wt% of white corundum powder, 18-26wt% of mullite powder, 15-23wt% of zirconium silicate powder, 15-23wt% of zirconium oxide powder, and 22-30wt% of cristobalite powder, and the sum of the contents of each substance is 100wt%.

[0013] In any of the above schemes, it is preferred that the mass percentage of each substance in the special additive is 3-8wt% of metal aluminum powder, 3-8wt% of metal silicon powder, 25-32wt% of mullite whisker, 25-32wt% of quartz glass whisker, 25-32wt% of alumina whisker, and 5-10wt% of graphene, and the sum of the contents of each substance is 100wt%.

[0014] The present invention also provides a method for preparing a high-yield silicon-based ceramic core for a nickel-based single crystal blade, which is used to prepare the high-yield silicon-based ceramic core for a nickel-based single crystal blade as described in any one of the above items, and comprises the following steps in order:

[0015] Step 1: Prepare core-shell structure quartz glass powder, mineralizer and special additives of various particle sizes according to the designed material ratio and process parameters;

[0016] Step 2: according to the designed material ratio, core-shell structure quartz glass powder of various particle sizes, fused quartz glass powder of various particle sizes, mineralizer, and special additives are put into a V-type mixer and mixed evenly to obtain silicon-based ceramic powder;

[0017] Step 3: Weigh the plasticizer according to the designed material ratio, and heat and melt the plasticizer in a vacuum mixer. After the plasticizer is completely melted, add the obtained silicon-based ceramic powder into the vacuum mixer, stir while adding, continue stirring for a certain time after all the silicon-based ceramic powder is added, and then evacuate to a certain vacuum degree, and continue stirring for a certain time at the vacuum degree to obtain a silicon-based ceramic core slurry;

[0018] Step 4: manufacturing a ceramic core mold according to the designed ceramic core structure, and injecting the silicon-based ceramic core slurry into the ceramic core mold by using an injection molding machine for filling and pressing to obtain a silicon-based ceramic core blank;

[0019] Step 5: Check the silicon-based ceramic core blank and confirm that there are no obvious defects in its appearance, then insert the silicon-based ceramic core blank into a calcined pot filled with mullite filler, and make the mullite filler completely cover the silicon-based ceramic core blank;

[0020] Step 6: Place the calcined pot containing the mullite filler and the silicon-based ceramic core blank into a calcining furnace for calcining. After the calcination is completed, a highly yielding silicon-based ceramic core can be obtained.

[0021] Preferably, in step 1, the method for preparing core-shell structured quartz glass powder of each particle size comprises the following steps in order:

[0022] Step (1): weighing the sol according to the designed material ratio, and placing the sol in a vacuum mixer for heating and stirring, with the stirring temperature being 18-35° C., the stirring speed being 45-85 r / min, and the stirring time being 30-90 min;

[0023] Step (2): weighing cristobalite according to the designed material ratio, placing the cristobalite in a vacuum mixer, and stirring it together with the melted sol, the stirring temperature is 18-35° C., the stirring speed is 45-85 r / min, and the stirring time is 60-180 min. After the stirring is completed, a premix of cristobalite and sol is obtained;

[0024] Step (3): according to the designed material ratio, fused silica glass powders of various particle sizes are weighed, and the fused silica glass powders of various particle sizes are placed in a vacuum mixer, and stirred together with the premix, the stirring temperature is 18-35° C., the stirring speed is 45-85 r / min, and the stirring time is 30-90 min; after the stirring is completed, evacuating to a vacuum degree not exceeding 0.06 MP, and continuing to stir at the vacuum degree, the stirring temperature is 18-35° C., the stirring speed is 45-85 r / min, and the stirring time is 180-360 min, after the stirring is completed, a mixture of fused silica glass powder, cristobalite and sol is obtained;

[0025] Step (4): taking out the mixture from the vacuum mixer and placing the mixture in an oven for drying at a temperature of 150-200° C. for a drying time of 120-180 min;

[0026] Step (5): placing the dried mixture into a roasting furnace for high-temperature roasting, wherein the high-temperature roasting process is as follows: heating the temperature from room temperature to 600°C at a heating rate of 3-8°C / min, and keeping the temperature for 3-5 hours; continuing to heating the temperature from 600°C to 960°C at a heating rate of 3-8°C / min, and keeping the temperature for 2-3 hours; continuing to heating the temperature from 960°C to 1250°C at a heating rate of 3-5°C / min, and keeping the temperature for 2-3 hours; continuing to heating the temperature from 1250°C to 1500-1600°C at a heating rate of 3-5°C / min, and keeping the temperature for 2-4 hours, and then cooling the mixture to room temperature in the furnace to obtain a sintered product of core-shell structured quartz glass powder; during the high-temperature roasting and furnace cooling process, argon gas protection is introduced, and the argon gas flow rate is 3-4 L / min;

[0027] Step (6): placing the sintered product of the core-shell structure quartz glass powder into a ball mill for ball milling, wherein the mass ratio of the sintered product of the core-shell structure quartz glass powder to the alumina ball milling beads is 1:2, the diameter of the alumina ball milling beads is 3 mm, the ball milling speed is 30-90 r / min, and the ball milling time is 120-150 min;

[0028] Step (7): After the ball milling is completed, screening is performed according to the designed particle sizes to obtain core-shell structured quartz glass powders of various particle sizes.

[0029] In any of the above schemes, preferably, in step one, the preparation method of the mineralizer is: according to the designed material ratio, white corundum powder, mullite powder, zirconium silicate powder, zirconium oxide powder and cristobalite powder are put into a V-type mixer and mixed evenly, the mixing speed is 30-50r / min, and the mixing time is 1-3h.

[0030] In any of the above schemes, preferably, in step one, the preparation method of the special additive is: according to the designed material ratio, metal aluminum powder, metal silicon powder, mullite whisker, quartz glass whisker, alumina whisker, and graphene are placed in a V-type mixer and mixed evenly, the mixing speed is 30-50r / min, and the mixing time is 1-3h.

[0031] In any of the above schemes, preferably, in step 2, the mixing speed of the core-shell structure quartz glass powder of each particle size, the fused quartz glass powder of each particle size, the mineralizer, and the special additive is 50-100 r / min and the mixing time is 2-4 h.

[0032] In any of the above schemes, preferably, in step three, the plasticizer is paraffin and / or beeswax, and the amount of the plasticizer added is 15-30wt% of the total mass of the core-shell structure quartz glass powder of each particle size, the fused quartz glass powder of each particle size, the mineralizer, and the special additive. The melting temperature of the plasticizer is 75-125°C and the melting time is 1-3h; the feeding rate of the silicon-based ceramic powder is 4-6kg / min, the stirring temperature is 75-125°C, the stirring speed is 60-90r / min, and the stirring time after all the silicon-based ceramic powder is added is continued for 8-12h; the vacuum degree does not exceed 0.06MPa, and the stirring time is continued for 2-3h at this vacuum degree.

[0033] In any of the above schemes, preferably, in step 4, the pressing parameters of the silicon-based ceramic core blank are: injection temperature 75-120°C, injection time 5-30s, injection pressure 2-7.5MPa, and holding time 30-60s.

[0034] In any of the above schemes, preferably, in step six, the sintering parameters of the silicon-based ceramic core blank are: sintering temperature 1100-1250° C., sintering time 5-10 h.

[0035] In the present invention, the V-shaped mixer, vacuum mixer, injection molding machine, roasting furnace, oven, ball mill, etc. used are all traditional equipment, and there are no special requirements for the equipment structure and model. The manufacturing process of the ceramic core mold is a traditional process, and there are no special requirements for the process flow, process parameters, mold materials, manufacturing equipment, etc. The pressing process of the ceramic core blank is also a traditional process, and there are no special requirements for the process flow, process parameters, pressing equipment, etc. It only needs to ensure that several key pressing parameters such as injection temperature, injection time, injection pressure, and holding time meet the requirements of the present invention.

[0036] In the present invention, the core-shell structure quartz glass powder includes six particle sizes, which are 75-150μm, 48-75μm, 38-48μm, 25-38μm, 20-25μm, and 0-20μm, that is, 75μm≤particle size<150μm, 48μm≤particle size<75μm, 38μm≤particle size<48μm, 25μm≤particle size<38μm, 20μm≤particle size<25μm, and 0μm≤particle size<20μm; the fused quartz glass powder in the core-shell structure quartz glass powder includes four particle sizes, which are 48-65μm, 35-48μm, 20-35 μm, 5-20μm, that is, 48μm≤particle size<65μm, 35μm≤particle size<48μm, 20μm≤particle size<35μm, 5μm≤particle size<20μm; the fused quartz glass powder in the silicon-based ceramic core includes four particle sizes, namely 35-62μm, 18-35μm, 5-18μm, 0.5-5μm, that is, 35μm≤particle size<62μm, 18μm≤particle size<35μm, 5μm≤particle size<18μm, 0.5μm≤particle size<5μm; cristobalite includes a particle size of 1-10μm, that is, 1μm≤particle size<10μm. For each particle size, the material passes through the upper and lower sieve holes in sequence to obtain a particle size between the upper and lower sieve holes, for example: the particle size is 20-25μm (20μm≤particle size<25μm), that is, the material passes through the 25μm sieve hole and the 20μm sieve hole in sequence to obtain a particle size between 20-25μm.

[0037] In the present invention, in the entire preparation process of the silicon-based ceramic core, the grading of the core-shell structured quartz glass powder and the content of each grade, the preparation process and process parameters of the core-shell structured quartz glass powder of each particle size, the ratio of other substances, other process parameters, etc. are all very important. Each parameter needs to work synergistically to achieve the expected technical effect of the present invention.

[0038] The high-yield silicon-based ceramic core for nickel-based single crystal blades of the present invention and the preparation method thereof have the following beneficial effects:

[0039] (1) A core-shell structured quartz glass powder is prepared by pre-treating fused quartz glass powder. The core-shell structured quartz glass powder has the characteristics of an outer structure of a cristobalite phase and a core structure of a glass phase, and the overall structure is a new structure of a cristobalite-coated glass phase. At the same time, the outer layer of the core-shell structured quartz glass powder has a large number of divergent microcracks, which can achieve the regulation of high-temperature strength and high-temperature shrinkage when preparing a silicon-based ceramic core.

[0040] (2) When preparing core-shell structured quartz glass powder, different sol materials can regulate the size and number of microcracks, thereby regulating the high-temperature strength, high-temperature creep and high-temperature shrinkage properties of the silicon-based ceramic core.

[0041] (3) By controlling the grading and addition amount of core-shell structure quartz glass powder, the type and addition amount of mineralizer, the type and addition amount of additive, and the grading and addition amount of fused quartz glass powder, the preparation of high-yield silicon-based ceramic core can be achieved.

[0042] (4) The microstructure of the high-yield silicon-based ceramic core has the characteristics of annular layered microcrack toughening structure, and its microphase composition has the characteristics of a layered cross structure of glass phase and quartz phase. This new structure enables the silicon-based ceramic core to have excellent shrinkage yield, strength yield and creep yield characteristics during the solidification process of high-temperature alloy liquid, effectively solving the problem of recrystallization in the inner cavity of nickel-based single crystal high-temperature alloy blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A flow chart of a preferred embodiment of a high-yield silicon-based ceramic core for a nickel-based single crystal blade and a method for preparing the same according to the present invention;

[0044] Figure 2 for Figure 1 The microscopic morphology of the sol-modified core-shell structured quartz glass powder prepared in the embodiment shown;

[0045] Figure 3 for Figure 1 The microstructure of the high yielding silicon-based ceramic core prepared in the embodiment shown contains special additive whisker toughening and microcrack toughening;

[0046] Figure 4 To adopt Figure 1 Partial photo of the blade made of the high-yield silicon-based ceramic core of the embodiment shown (no recrystallization in the blade cavity);

[0047] Figure 5 The microscopic morphology of the sol-modified core-shell structure quartz glass powder prepared according to another preferred embodiment of the nickel-based single crystal blade high-yield silicon-based ceramic core and the preparation method thereof of the present invention;

[0048] Figure 6for Figure 5 The microscopic morphology of the highly yielding silicon-based ceramic core with microcrack toughening prepared in the illustrated embodiment;

[0049] Figure 7 for Figure 5 The microscopic morphology of the highly yielding silicon-based ceramic core with microcrack toughening prepared in the embodiment shown (partial magnification);

[0050] Figure 8 To adopt Figure 5 Partial photo of the blade made of the high-yield silicon-based ceramic core of the embodiment shown (no recrystallization in the blade cavity);

[0051] Fig. 9 This is a partial photo of a blade made using the silicon-based ceramic core of the comparative example (there is recrystallization in the inner cavity of the blade).

[0052] Notes in the figure: 1-core, 2-shell, 3-microcracks, 4-special additive whisker toughening, 5-microcrack toughening, 6-inner cavity recrystallization. DETAILED DESCRIPTION

[0053] In order to further understand the content of the present invention, the present invention will be described in detail below in conjunction with specific embodiments.

[0054] Embodiment 1:

[0055] According to a preferred embodiment of the high-yield silicon-based ceramic core for nickel-based single crystal blades of the present invention, the mass percentage of each substance in the silicon-based ceramic core is 20wt% of core-shell structure quartz glass powder, 75wt% of fused quartz glass powder, 3wt% of mineralizer, and 2wt% of special additive. The mass percentage of each substance in the core-shell structure quartz glass powder is 30wt% of fused quartz glass powder, 45wt% of sol, and 25wt% of cristobalite.

[0056] The core-shell structure quartz glass powder includes six particle sizes, namely 75-150μm, 48-75μm, 38-48μm, 25-38μm, 20-25μm, and 0-20μm; the mass percentage of each particle size in the core-shell structure quartz glass powder is as follows: 75-150μm accounts for 10wt%, 48-75μm accounts for 25wt%, 38-48μm accounts for 35wt%, 25-38μm accounts for 10wt%, 20-25μm accounts for 15wt%, and 0-20μm accounts for 5wt%.

[0057] The fused silica glass powder in the core-shell structured silica glass powder includes four particle sizes, namely 48-65μm, 35-48μm, 20-35μm, and 5-20μm; the mass percentage of each particle size in the fused silica glass powder is 30wt% for particle size 48-65μm, 30wt% for particle size 35-48μm, 30wt% for particle size 20-35μm, and 10wt% for particle size 5-20μm. The sol is selected from silica sol; the cristobalite includes a particle size of 1-10μm.

[0058] The fused quartz glass powder in the silicon-based ceramic core includes four particle sizes, namely 35-62μm, 18-35μm, 5-18μm, and 0.5-5μm; the mass percentage of each particle size in the quartz glass powder is as follows: 35wt% for 35-62μm, 25wt% for 18-35μm, 35wt% for 5-18μm, and 5wt% for 0.5-5μm.

[0059] The mass percentage of each substance in the mineralizer is 22wt% of white corundum powder, 26wt% of mullite powder, 15wt% of zirconium silicate powder, 15wt% of zirconium oxide powder, and 22wt% of cristobalite powder. The mass percentage of each substance in the special additive is 3wt% of metal aluminum powder, 8wt% of metal silicon powder, 25wt% of mullite whisker, 32wt% of quartz glass whisker, 25wt% of aluminum oxide whisker, and 7wt% of graphene.

[0060] like Figure 1 As shown, this embodiment also provides a method for preparing a high-yield silicon-based ceramic core for a nickel-based single crystal blade, which is used to prepare the high-yield silicon-based ceramic core for the nickel-based single crystal blade, and includes the following steps in order:

[0061] Step 1: Prepare core-shell structure quartz glass powder, mineralizer and special additives of various particle sizes according to the designed material ratio and process parameters;

[0062] Step 2: according to the designed material ratio, core-shell structure quartz glass powder of various particle sizes, fused quartz glass powder of various particle sizes, mineralizer, and special additives are put into a V-type mixer and mixed evenly to obtain silicon-based ceramic powder;

[0063] Step 3: Weigh the plasticizer according to the designed material ratio, and heat and melt the plasticizer in a vacuum mixer. After the plasticizer is completely melted, add the obtained silicon-based ceramic powder into the vacuum mixer, stir while adding, continue stirring for a certain time after all the silicon-based ceramic powder is added, and then evacuate to a certain vacuum degree, and continue stirring for a certain time at the vacuum degree to obtain a silicon-based ceramic core slurry;

[0064] Step 4: manufacturing a ceramic core mold according to the designed ceramic core structure, and injecting the silicon-based ceramic core slurry into the ceramic core mold by using an injection molding machine for filling and pressing to obtain a silicon-based ceramic core blank;

[0065] Step 5: Check the silicon-based ceramic core blank and confirm that there are no obvious defects in its appearance, then insert the silicon-based ceramic core blank into a calcined pot filled with mullite filler, and make the mullite filler completely cover the silicon-based ceramic core blank;

[0066] Step 6: Place the calcined pot containing the mullite filler and the silicon-based ceramic core blank into a calcining furnace for calcining. After the calcination is completed, a highly yielding silicon-based ceramic core can be obtained.

[0067] In step 1, the method for preparing core-shell structured quartz glass powder of various particle sizes comprises the following steps in order:

[0068] Step (1): weighing the sol according to the designed material ratio, and placing the sol in a vacuum mixer for heating and stirring, with the stirring temperature being 18° C., the stirring speed being 45 r / min, and the stirring time being 90 min;

[0069] Step (2): weighing cristobalite according to the designed material ratio, placing the cristobalite in a vacuum mixer, and stirring it together with the melted sol, the stirring temperature is 18° C., the stirring speed is 45 r / min, and the stirring time is 180 min. After the stirring is completed, a premix of cristobalite and sol is obtained;

[0070] Step (3): according to the designed material ratio, fused silica glass powders of various particle sizes are weighed, and the fused silica glass powders of various particle sizes are placed in a vacuum mixer, and stirred together with the premix, the stirring temperature is 18° C., the stirring speed is 45 r / min, and the stirring time is 90 min; after the stirring is completed, evacuating to a vacuum degree not exceeding 0.06 MP, and continuing to stir at the vacuum degree, the stirring temperature is 18° C., the stirring speed is 45 r / min, and the stirring time is 360 min. After the stirring is completed, a mixture of fused silica glass powder, cristobalite and sol is obtained;

[0071] Step (4): taking out the mixture from the vacuum mixer and placing the mixture into an oven for drying at a temperature of 150° C. for a drying time of 180 min;

[0072] Step (5): placing the dried mixture into a roasting furnace for high-temperature roasting, wherein the high-temperature roasting process is as follows: heating the temperature from room temperature to 600°C at a heating rate of 3°C / min, and keeping the temperature for 5 hours; continuing to heating the temperature from 600°C to 960°C at a heating rate of 3°C / min, and keeping the temperature for 3 hours; continuing to heating the temperature from 960°C to 1250°C at a heating rate of 3°C / min, and keeping the temperature for 3 hours; continuing to heating the temperature from 1250°C to 1500°C at a heating rate of 3°C / min, and keeping the temperature for 4 hours, and then cooling the mixture to room temperature in the furnace to obtain a sintered product of core-shell structured quartz glass powder; during the high-temperature roasting and furnace cooling process, argon gas protection is introduced, and the argon gas flow rate is 3 L / min;

[0073] Step (6): placing the sintered product of the core-shell structure quartz glass powder into a ball mill for ball milling, wherein the mass ratio of the sintered product of the core-shell structure quartz glass powder to the alumina ball milling beads is 1:2, the diameter of the alumina ball milling beads is 3 mm, the ball milling speed is 30 r / min, and the ball milling time is 150 min;

[0074] Step (7): After the ball milling is completed, screening is performed according to the designed particle sizes to obtain core-shell structured quartz glass powders of various particle sizes.

[0075] In step 1, the preparation method of the mineralizer is: according to the designed material ratio, white corundum powder, mullite powder, zirconium silicate powder, zirconium oxide powder, and cristobalite powder are put into a V-type mixer and mixed evenly, the mixing speed is 30r / min, and the mixing time is 3h. The preparation method of the special additive is: according to the designed material ratio, metal aluminum powder, metal silicon powder, mullite whisker, quartz glass whisker, aluminum oxide whisker, and graphene are put into a V-type mixer and mixed evenly, the mixing speed is 30r / min, and the mixing time is 3h.

[0076] In step 2, the mixing speed of the core-shell structure quartz glass powder of each particle size, the fused quartz glass powder of each particle size, the mineralizer, and the special additive is 50 r / min and the mixing time is 4 hours.

[0077] In step three, paraffin is selected as the plasticizer, and the amount of the plasticizer added is 15wt% of the total mass of the core-shell structure quartz glass powder of each particle size, the fused quartz glass powder of each particle size, the mineralizer, and the special additive. The melting temperature of the plasticizer is 75°C and the melting time is 3h; the feeding rate of the silicon-based ceramic powder is 4kg / min, the stirring temperature is 75°C, the stirring speed is 60r / min, and the stirring time is continued for 12h after all the silicon-based ceramic powder is added; the vacuum degree does not exceed 0.06MPa, and the stirring time is continued for 3h at this vacuum degree.

[0078] In step 4, the pressing parameters of the silicon-based ceramic core blank are: injection temperature 75° C., injection time 30 s, injection pressure 2 MPa, and holding time 60 s.

[0079] In step six, the sintering parameters of the silicon-based ceramic core blank are: sintering temperature 1100° C., sintering time 10 h.

[0080] In this embodiment, the microscopic morphology of the prepared sol-modified core-shell structure quartz glass powder is as follows: Figure 2 As shown, its microstructure includes core 1, shell 2, and microcrack 3; the microstructure of the prepared high-yield silicon-based ceramic core containing special additive whisker toughening and microcrack toughening is as shown Figure 3 As shown, its microscopic morphology includes special additive whisker toughening 4 and microcrack toughening 5; a partial photo of a blade prepared using the high yield silicon-based ceramic core of this embodiment is shown in Figure 4 As shown, the figure shows that there is no recrystallization in the blade cavity.

[0081] The high-yield silicon-based ceramic core for nickel-based single crystal blades of this embodiment and the preparation method thereof have the following beneficial effects: (1) By pre-treating the fused silica glass powder, a core-shell structured silica glass powder is prepared in advance. The core-shell structured silica glass powder has the characteristics of an outer structure of quartz phase and a core structure of glass phase, and the overall structure is a new structure of quartz coated with glass phase; at the same time, the outer layer of the core-shell structured silica glass powder has a large number of divergent microcracks, and these microcracks can achieve the regulation of high-temperature strength and high-temperature shrinkage when preparing the silicon-based ceramic core. (2) When preparing the core-shell structured silica glass powder, different sol materials can regulate the size and number of microcracks, and then regulate the high-temperature strength, high-temperature creep and high-temperature shrinkage properties of the silicon-based ceramic core. (3) By controlling the grading and addition amount of the core-shell structured silica glass powder, the type and addition amount of the mineralizer, the type and addition amount of the additive, and the grading and addition amount of the fused silica glass powder, the preparation of the high-yield silicon-based ceramic core can be achieved. (4) The microstructure of the high-yield silicon-based ceramic core has the characteristics of annular layered microcrack toughening structure, and its microphase composition has the characteristics of a layered cross structure of glass phase and quartz phase. This new structure enables the silicon-based ceramic core to have excellent shrinkage yield, strength yield and creep yield characteristics during the solidification process of high-temperature alloy liquid, effectively solving the problem of recrystallization in the inner cavity of nickel-based single crystal high-temperature alloy blades.

[0082] Embodiment 2:

[0083] According to another preferred embodiment of the present invention, the high-yield silicon-based ceramic core for nickel-based single crystal blades and the preparation method thereof, the material ratio, preparation process, technical principle, beneficial effects, etc. are basically the same as those of the first embodiment, except that:

[0084] The mass percentage of each substance in the silicon-based ceramic core is 65wt% of core-shell structure quartz glass powder, 30wt% of fused quartz glass powder, 3wt% of mineralizer, and 2wt% of special additives. The mass percentage of each substance in the core-shell structure quartz glass powder is 55wt% of fused quartz glass powder, 20wt% of sol, and 25wt% of cristobalite.

[0085] The core-shell structure quartz glass powder includes six particle sizes, namely 75-150μm, 48-75μm, 38-48μm, 25-38μm, 20-25μm, and 0-20μm; the mass percentage of each particle size in the core-shell structure quartz glass powder is as follows: 75-150μm accounts for 25wt%, 48-75μm accounts for 10wt%, 38-48μm accounts for 20wt%, 25-38μm accounts for 25wt%, 20-25μm accounts for 10wt%, and 0-20μm accounts for 10wt%.

[0086] The fused silica glass powder in the core-shell structured silica glass powder includes four particle sizes, namely 48-65μm, 35-48μm, 20-35μm, and 5-20μm; the mass percentage of each particle size in the fused silica glass powder is 50wt% for particle size 48-65μm, 20wt% for particle size 35-48μm, 20wt% for particle size 20-35μm, and 10wt% for particle size 5-20μm. The sol is selected from aluminum sol; the cristobalite includes a particle size of 1-10μm.

[0087] The fused quartz glass powder in the silicon-based ceramic core includes four particle sizes, namely 35-62μm, 18-35μm, 5-18μm, and 0.5-5μm; the mass percentage of each particle size in the quartz glass powder is as follows: 35-62μm accounts for 48wt%, 18-35μm accounts for 18wt%, 5-18μm accounts for 24wt%, and 0.5-5μm accounts for 10wt%.

[0088] The mass percentage of each substance in the mineralizer is 25wt% of white corundum powder, 18wt% of mullite powder, 15wt% of zirconium silicate powder, 15wt% of zirconium oxide powder, and 27wt% of cristobalite powder. The mass percentage of each substance in the special additive is 8wt% of metal aluminum powder, 3wt% of metal silicon powder, 32wt% of mullite whisker, 25wt% of quartz glass whisker, 27wt% of aluminum oxide whisker, and 5wt% of graphene.

[0089] In step 1, the method for preparing core-shell structured quartz glass powder of various particle sizes comprises the following steps in order:

[0090] Step (1): weighing the sol according to the designed material ratio, and placing the sol in a vacuum mixer for heating and stirring at a stirring temperature of 35° C., a stirring speed of 85 r / min, and a stirring time of 30 min;

[0091] Step (2): weighing cristobalite according to the designed material ratio, placing the cristobalite in a vacuum mixer, and stirring it together with the melted sol, the stirring temperature is 35° C., the stirring speed is 85 r / min, and the stirring time is 60 min. After the stirring is completed, a premix of cristobalite and sol is obtained;

[0092] Step (3): according to the designed material ratio, fused silica glass powders of various particle sizes are weighed, and the fused silica glass powders of various particle sizes are placed in a vacuum mixer, and stirred together with the premix, the stirring temperature is 35° C., the stirring speed is 85 r / min, and the stirring time is 30 min; after the stirring is completed, evacuating to a vacuum degree not exceeding 0.06 MP, and continuing to stir at this vacuum degree, the stirring temperature is 35° C., the stirring speed is 85 r / min, and the stirring time is 180 min. After the stirring is completed, a mixture of fused silica glass powder, cristobalite and sol is obtained;

[0093] Step (4): taking out the mixture from the vacuum mixer and placing the mixture in an oven for drying at a temperature of 200° C. for 120 min;

[0094] Step (5): placing the dried mixture into a roasting furnace for high-temperature roasting, wherein the high-temperature roasting process is as follows: heating the temperature from room temperature to 600°C at a heating rate of 8°C / min, and keeping the temperature for 3 hours; continuing to heating the temperature from 600°C to 960°C at a heating rate of 8°C / min, and keeping the temperature for 2 hours; continuing to heating the temperature from 960°C to 1250°C at a heating rate of 5°C / min, and keeping the temperature for 2 hours; continuing to heating the temperature from 1250°C to 1600°C at a heating rate of 5°C / min, and keeping the temperature for 2 hours, and then cooling the mixture to room temperature in the furnace to obtain a sintered product of core-shell structured quartz glass powder; during the high-temperature roasting and furnace cooling process, argon gas protection is introduced, and the argon gas flow rate is 4 L / min;

[0095] Step (6): placing the sintered product of the core-shell structure quartz glass powder into a ball mill for ball milling, wherein the mass ratio of the sintered product of the core-shell structure quartz glass powder to the alumina ball milling beads is 1:2, the diameter of the alumina ball milling beads is 3 mm, the ball milling speed is 90 r / min, and the ball milling time is 120 min;

[0096] Step (7): After the ball milling is completed, screening is performed according to the designed particle sizes to obtain core-shell structured quartz glass powders of various particle sizes.

[0097] In step 1, the preparation process parameters of the mineralizer are: the mixing speed of white corundum powder, mullite powder, zirconium silicate powder, zirconium oxide powder, and cristobalite powder is 50r / min, and the mixing time is 1h. The preparation process parameters of the special additives are: the mixing speed of metal aluminum powder, metal silicon powder, mullite whisker, quartz glass whisker, aluminum oxide whisker, and graphene is 50r / min, and the mixing time is 1h.

[0098] In step 2, the mixing speed of the core-shell structure quartz glass powder of each particle size, the fused quartz glass powder of each particle size, the mineralizer, and the special additive is 100 r / min and the mixing time is 2 h.

[0099] In step three, beeswax is selected as a plasticizer, and the amount of the plasticizer added is 30wt% of the total mass of core-shell structure quartz glass powder of each particle size, fused quartz glass powder of each particle size, mineralizer, and special additives. The melting temperature of the plasticizer is 125°C and the melting time is 1h; the feeding rate of the silicon-based ceramic powder is 6kg / min, the stirring temperature is 125°C, the stirring speed is 90r / min, and the stirring time is continued for 8h after all the silicon-based ceramic powder is added; the vacuum degree does not exceed 0.06MPa, and the stirring time is continued for 2h at this vacuum degree.

[0100] In step 4, the pressing parameters of the silicon-based ceramic core blank are: injection temperature 120° C., injection time 5 s, injection pressure 7.5 MPa, and holding time 30 s.

[0101] In step six, the sintering parameters of the silicon-based ceramic core blank are: sintering temperature 1250° C., sintering time 5 h.

[0102] In this embodiment, the microscopic morphology of the prepared sol-modified core-shell structure quartz glass powder is as follows: Figure 5 As shown, its microstructure includes core 1, shell 2, and microcrack 3; the microstructure of the prepared high-yield silicon-based ceramic core with microcrack toughening is as follows Figure 6 and Figure 7 As shown, its microscopic morphology includes microcrack toughening 5; a partial photo of the blade prepared using the high yield silicon-based ceramic core of this embodiment is shown in Figure 8 As shown, the figure shows that there is no recrystallization in the blade cavity.

[0103] Embodiment three:

[0104] According to another preferred embodiment of the present invention, the high-yield silicon-based ceramic core for nickel-based single crystal blades and the preparation method thereof, the material ratio, preparation process, technical principle, beneficial effects, etc. are basically the same as those of the first embodiment, except that:

[0105] The mass percentage of each substance in the silicon-based ceramic core is: 45wt% of core-shell structure quartz glass powder, 35wt% of fused quartz glass powder, 10wt% of mineralizer, and 10wt% of special additives. The mass percentage of each substance in the core-shell structure quartz glass powder is: 40wt% of fused quartz glass powder, 30wt% of sol, and 30wt% of cristobalite.

[0106] The core-shell structure quartz glass powder includes six particle sizes, namely 75-150μm, 48-75μm, 38-48μm, 25-38μm, 20-25μm, and 0-20μm; the mass percentage of each particle size in the core-shell structure quartz glass powder is as follows: 75-150μm accounts for 20wt%, 48-75μm accounts for 20wt%, 38-48μm accounts for 30wt%, 25-38μm accounts for 17wt%, 20-25μm accounts for 5wt%, and 0-20μm accounts for 8wt%.

[0107] The fused silica glass powder in the core-shell structured silica glass powder includes four particle sizes, namely 48-65μm, 35-48μm, 20-35μm, and 5-20μm; the mass percentage of each particle size in the fused silica glass powder is 45wt% for particle size 48-65μm, 25wt% for particle size 35-48μm, 25wt% for particle size 20-35μm, and 5wt% for particle size 5-20μm. The sol is selected as yttrium sol; the cristobalite includes a particle size of 1-10μm.

[0108] The fused quartz glass powder in the silicon-based ceramic core includes four particle sizes, namely 35-62μm, 18-35μm, 5-18μm, and 0.5-5μm; the mass percentage of each particle size in the quartz glass powder is as follows: 35-62μm accounts for 40wt%, 18-35μm accounts for 22wt%, 5-18μm accounts for 30wt%, and 0.5-5μm accounts for 8wt%.

[0109] The mass percentage of each substance in the mineralizer is 24wt% of white corundum powder, 19wt% of mullite powder, 17wt% of zirconium silicate powder, 17wt% of zirconium oxide powder, and 23wt% of cristobalite powder. The mass percentage of each substance in the special additive is 5wt% of metal aluminum powder, 5wt% of metal silicon powder, 28wt% of mullite whisker, 28wt% of quartz glass whisker, 27wt% of aluminum oxide whisker, and 7wt% of graphene.

[0110] In step 1, the method for preparing core-shell structured quartz glass powder of various particle sizes comprises the following steps in order:

[0111] Step (1): weighing the sol according to the designed material ratio, and placing the sol in a vacuum mixer for heating and stirring, with the stirring temperature being 26° C., the stirring speed being 65 r / min, and the stirring time being 60 min;

[0112] Step (2): weighing cristobalite according to the designed material ratio, placing the cristobalite in a vacuum mixer, and stirring it together with the melted sol, the stirring temperature is 26° C., the stirring speed is 65 r / min, and the stirring time is 120 min. After the stirring is completed, a premix of cristobalite and sol is obtained;

[0113] Step (3): according to the designed material ratio, fused silica glass powders of various particle sizes are weighed, and the fused silica glass powders of various particle sizes are placed in a vacuum mixer, and stirred together with the premix, the stirring temperature is 26° C., the stirring speed is 65 r / min, and the stirring time is 60 min; after the stirring is completed, evacuating to a vacuum degree not exceeding 0.06 MP, and continuing to stir at this vacuum degree, the stirring temperature is 26° C., the stirring speed is 65 r / min, and the stirring time is 270 min. After the stirring is completed, a mixture of fused silica glass powder, cristobalite and sol is obtained;

[0114] Step (4): taking out the mixture from the vacuum mixer and placing the mixture in an oven for drying at a temperature of 180° C. for a drying time of 150 min;

[0115] Step (5): placing the dried mixture into a roasting furnace for high-temperature roasting, wherein the high-temperature roasting process is as follows: heating the temperature from room temperature to 600°C at a heating rate of 5°C / min, and keeping the temperature for 4 hours; continuing to heating the temperature from 600°C to 960°C at a heating rate of 5°C / min, and keeping the temperature for 2.5 hours; continuing to heating the temperature from 960°C to 1250°C at a heating rate of 4°C / min, and keeping the temperature for 2.5 hours; continuing to heating the temperature from 1250°C to 1550°C at a heating rate of 4°C / min, and keeping the temperature for 3 hours, and then cooling the mixture to room temperature in the furnace to obtain a sintered product of core-shell structured quartz glass powder; during the high-temperature roasting and furnace cooling process, argon gas protection is introduced, and the argon gas flow rate is 3.5 L / min;

[0116] Step (6): placing the sintered product of the core-shell structure quartz glass powder into a ball mill for ball milling, wherein the mass ratio of the sintered product of the core-shell structure quartz glass powder to the alumina ball milling beads is 1:2, the diameter of the alumina ball milling beads is 3 mm, the ball milling speed is 60 r / min, and the ball milling time is 135 min;

[0117] Step (7): After the ball milling is completed, screening is performed according to the designed particle sizes to obtain core-shell structured quartz glass powders of various particle sizes.

[0118] In step 1, the preparation process parameters of the mineralizer are: the mixing speed of white corundum powder, mullite powder, zirconium silicate powder, zirconium oxide powder, and cristobalite powder is 40r / min, and the mixing time is 2h. The preparation process parameters of the special additives are: the mixing speed of metal aluminum powder, metal silicon powder, mullite whisker, quartz glass whisker, aluminum oxide whisker, and graphene is 40r / min, and the mixing time is 2h.

[0119] In step 2, the mixing speed of the core-shell structure quartz glass powder of each particle size, the fused quartz glass powder of each particle size, the mineralizer, and the special additive is 80 r / min and the mixing time is 3 h.

[0120] In step three, beeswax is selected as a plasticizer, and the amount of the plasticizer added is 22wt% of the total mass of core-shell structure quartz glass powder of each particle size, fused quartz glass powder of each particle size, mineralizer, and special additives. The melting temperature of the plasticizer is 100°C and the melting time is 2h; the feeding rate of the silicon-based ceramic powder is 5kg / min, the stirring temperature is 100°C, the stirring speed is 75r / min, and the stirring time is continued for 10h after all the silicon-based ceramic powder is added; the vacuum degree does not exceed 0.06MPa, and the stirring time is continued for 2.5h at this vacuum degree.

[0121] In step 4, the pressing parameters of the silicon-based ceramic core blank are: injection temperature 98° C., injection time 20 s, injection pressure 5 MPa, and holding time 45 s.

[0122] In step six, the sintering parameters of the silicon-based ceramic core blank are: sintering temperature 1200° C., sintering time 8 h.

[0123] Comparative Example:

[0124] The silicon-based ceramic core material of this comparative example is composed of fused quartz glass powder, mineralizer, and special additives, and no core-shell structured quartz glass powder is added. The mass percentage of each substance in the silicon-based ceramic core material is 80wt% of fused quartz glass powder, 10wt% of mineralizer, and 10wt% of special additive. The specific substances selected, the grading of the fused quartz glass powder, the ratio of each substance in the mineralizer, the ratio of each substance in the special additive, etc. are the same as those in Example 1; the preparation process and process parameters of the silicon-based ceramic core material are also basically the same as those in Example 1, wherein the preparation step of the core-shell structured quartz glass powder is deleted. A partial photo of the blade prepared using the silicon-based ceramic core material of the comparative example is shown in the figure. Fig. 9 As shown in the figure, it can be seen that the blade produces inner cavity recrystallization 6.

[0125] The chemical reagents, powder materials, etc. used in the above examples were purchased from Aladdin Reagent Co., Ltd. and Sinopharm Chemical Reagent Co., Ltd.

[0126] Special note: The technical solution of the present invention involves many parameters, and the synergistic effects between the various parameters need to be comprehensively considered in order to obtain the beneficial effects and significant progress of the present invention. Moreover, the value ranges of each parameter in the technical solution are obtained after a large number of experiments. For each parameter and the combination of each parameter, the inventors have recorded a large amount of test data. Due to space limitations, the specific test data are not disclosed here. It is not difficult for those skilled in the art to understand that the high-yield silicon-based ceramic core for nickel-based single crystal blades of the present invention and the preparation method thereof include any combination of the invention content and specific implementation methods of the above-mentioned specification of the present invention and the various parts shown in the accompanying drawings. Due to space limitations and to make the specification concise, the various schemes consisting of these combinations are not described one by one. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-yield silicon-based ceramic core for nickel-based single crystal blades, characterized in that: The mass percentage of each substance in the silicon-based ceramic core is: 20-65wt% of core-shell structure quartz glass powder, 30-75wt% of fused quartz glass powder, 3-35wt% of mineralizer, 1-10wt% of special additive, and the sum of the contents of each substance is 100wt%; The mass percentage of each substance in the core-shell structure quartz glass powder is 30-55wt% of fused quartz glass powder, 20-45wt% of sol, and 25-50wt% of cristobalite, and the sum of the contents of each substance is 100wt%; The core-shell structure quartz glass powder includes six particle sizes, namely 75μm≤particle size<150μm, 48μm≤particle size<75μm, 38μm≤particle size<48μm, 25μm≤particle size<38μm, 20μm≤particle size<25μm, and 0μm<particle size<20μm; the mass percentage of each particle size in the core-shell structure quartz glass powder is 10-25wt% of 75μm≤particle size<150μm, 10-25wt% of 48μm≤particle size<75μm, 20-35wt% of 38μm≤particle size<48μm, 10-25wt% of 25μm≤particle size<38μm, 5-15wt% of 20μm≤particle size<25μm, and 5-10wt% of 0μm<particle size<20μm, and the sum of the contents of the materials in each particle size is 100wt%; The fused silica glass powder in the core-shell structured silica glass powder includes four particle sizes, namely 48μm≤particle size<65μm, 35μm≤particle size<48μm, 20μm≤particle size<35μm, and 5μm≤particle size<20μm; the mass percentage of each particle size in the fused silica glass powder is 30-50wt% of 48μm≤particle size<65μm, 20-30wt% of 35μm≤particle size<48μm, 20-30wt% of 20μm≤particle size<35μm, and 5-10wt% of 5μm≤particle size<20μm, and the sum of the contents of each particle size material is 100wt%; The method for preparing core-shell structured quartz glass powder of various particle sizes comprises the following steps in order: Step (1): weighing the sol according to the designed material ratio, and placing the sol in a vacuum mixer for heating and stirring, with the stirring temperature being 18-35° C., the stirring speed being 45-85 r / min, and the stirring time being 30-90 min; Step (2): weighing cristobalite according to the designed material ratio, placing the cristobalite in a vacuum mixer, and stirring it together with the melted sol, the stirring temperature is 18-35° C., the stirring speed is 45-85 r / min, and the stirring time is 60-180 min. After the stirring is completed, a premix of cristobalite and sol is obtained; Step (3): according to the designed material ratio, fused silica glass powders of various particle sizes are weighed, and the fused silica glass powders of various particle sizes are placed in a vacuum mixer, and stirred together with the premix, the stirring temperature is 18-35° C., the stirring speed is 45-85 r / min, and the stirring time is 30-90 min; after the stirring is completed, evacuating to a vacuum degree not exceeding 0.06 MP, and continuing to stir at the vacuum degree, the stirring temperature is 18-35° C., the stirring speed is 45-85 r / min, and the stirring time is 180-360 min, after the stirring is completed, a mixture of fused silica glass powder, cristobalite and sol is obtained; Step (4): taking out the mixture from the vacuum mixer and placing the mixture in an oven for drying at a temperature of 150-200° C. for a drying time of 120-180 min; Step (5): placing the dried mixture into a roasting furnace for high-temperature roasting, wherein the high-temperature roasting process is as follows: heating the temperature from room temperature to 600°C at a heating rate of 3-8°C / min, and keeping the temperature for 3-5 hours; continuing to heating the temperature from 600°C to 960°C at a heating rate of 3-8°C / min, and keeping the temperature for 2-3 hours; continuing to heating the temperature from 960°C to 1250°C at a heating rate of 3-5°C / min, and keeping the temperature for 2-3 hours; continuing to heating the temperature from 1250°C to 1500-1600°C at a heating rate of 3-5°C / min, and keeping the temperature for 2-4 hours, and then cooling the mixture to room temperature in the furnace to obtain a sintered product of core-shell structured quartz glass powder; during the high-temperature roasting and furnace cooling process, argon gas protection is introduced, and the argon gas flow rate is 3-4 L / min; Step (6): placing the sintered product of the core-shell structure quartz glass powder into a ball mill for ball milling, wherein the mass ratio of the sintered product of the core-shell structure quartz glass powder to the alumina ball milling beads is 1:2, the diameter of the alumina ball milling beads is 3 mm, the ball milling speed is 30-90 r / min, and the ball milling time is 120-150 min; Step (7): After the ball milling is completed, screening is performed according to the designed particle sizes to obtain core-shell structured quartz glass powders of various particle sizes.

2. The high-yield silicon-based ceramic core for nickel-based single crystal blades according to claim 1, characterized in that: The sol includes any one or more of silica sol, aluminum sol, yttrium sol, zirconium sol and magnesium sol; the cristobalite includes a particle size range of 1-10 μm.

3. The high-yield silicon-based ceramic core for nickel-based single crystal blades according to claim 2, characterized in that: The fused quartz glass powder in the silicon-based ceramic core includes four particle sizes, namely 35μm≤particle size<62μm, 18μm≤particle size<35μm, 5μm≤particle size<18μm, and 0.5μm≤particle size<5μm; the mass percentage of each particle size in the quartz glass powder is 35-48wt% for 35μm≤particle size<62μm, 18-25wt% for 18μm≤particle size<35μm, 22-35wt% for 5μm≤particle size<18μm, and 5-10wt% for 0.5μm≤particle size<5μm, and the sum of the contents of materials in each particle size is 100wt%.

4. The high-yield silicon-based ceramic core for nickel-based single crystal blades according to claim 3, characterized in that: The mass percentage of each substance in the mineralizer is 22-30wt% of white corundum powder, 18-26wt% of mullite powder, 15-23wt% of zirconium silicate powder, 15-23wt% of zirconium oxide powder, and 22-30wt% of cristobalite powder, and the sum of the contents of each substance is 100wt%.

5. The high-yield silicon-based ceramic core for nickel-based single crystal blades according to claim 4, characterized in that: The mass percentage of each substance in the special additive is 3-8wt% of metal aluminum powder, 3-8wt% of metal silicon powder, 25-32wt% of mullite whisker, 25-32wt% of quartz glass whisker, 25-32wt% of alumina whisker, and 5-10wt% of graphene, and the sum of the contents of each substance is 100wt%.

6. A method for preparing a high-yield silicon-based ceramic core for a nickel-based single crystal blade, characterized in that: The method for preparing a high-yield silicon-based ceramic core for a nickel-based single crystal blade according to any one of claims 1 to 5 comprises the following steps in chronological order: Step 1: Prepare core-shell structure quartz glass powder, mineralizer and special additives of various particle sizes according to the designed material ratio and process parameters; Step 2: according to the designed material ratio, core-shell structure quartz glass powder of various particle sizes, fused quartz glass powder of various particle sizes, mineralizer, and special additives are put into a V-type mixer and mixed evenly to obtain silicon-based ceramic powder; Step 3: Weigh the plasticizer according to the designed material ratio, and heat and melt the plasticizer in a vacuum mixer. After the plasticizer is completely melted, add the obtained silicon-based ceramic powder into the vacuum mixer, stir while adding, continue stirring for a certain time after all the silicon-based ceramic powder is added, and then evacuate to a certain vacuum degree, and continue stirring for a certain time at the vacuum degree to obtain a silicon-based ceramic core slurry; Step 4: manufacturing a ceramic core mold according to the designed ceramic core structure, and injecting the silicon-based ceramic core slurry into the ceramic core mold by using an injection molding machine for filling and pressing to obtain a silicon-based ceramic core blank; Step 5: Check the silicon-based ceramic core blank and confirm that there are no obvious defects in its appearance, then insert the silicon-based ceramic core blank into a calcined pot filled with mullite filler, and make the mullite filler completely cover the silicon-based ceramic core blank; Step 6: Place the calcined pot containing the mullite filler and the silicon-based ceramic core blank into a calcining furnace for calcining. After the calcination is completed, a highly yielding silicon-based ceramic core can be obtained.

7. The method for preparing a high-yield silicon-based ceramic core for a nickel-based single crystal blade according to claim 6, characterized in that: In step 1, the preparation method of the mineralizer is to put white corundum powder, mullite powder, zirconium silicate powder, zirconium oxide powder and cristobalite powder into a V-type mixer according to the designed material ratio and mix them evenly at a mixing speed of 30-50 r / min and a mixing time of 1-3 h; In step 1, the preparation method of the special additive is to put metal aluminum powder, metal silicon powder, mullite whisker, quartz glass whisker, alumina whisker, and graphene into a V-type mixer according to the designed material ratio and mix them evenly, with a mixing speed of 30-50r / min and a mixing time of 1-3h; In step 2, the mixing speed of core-shell quartz glass powder of each particle size, fused quartz glass powder of each particle size, mineralizer, and special additive is 50-100 r / min and the mixing time is 2-4 h; In step three, the plasticizer is paraffin and / or beeswax, and the amount of the plasticizer added is 15-30wt% of the total mass of the core-shell structure quartz glass powder of each particle size, the fused quartz glass powder of each particle size, the mineralizer, and the special additive. The melting temperature of the plasticizer is 75-125°C and the melting time is 1-3h; the feeding rate of the silicon-based ceramic powder is 4-6kg / min, the stirring temperature is 75-125°C, the stirring speed is 60-90r / min, and the stirring time after all the silicon-based ceramic powder is added is 8-12h; the vacuum degree does not exceed 0.06MPa, and the stirring time is continued for 2-3h at this vacuum degree; In step 4, the pressing parameters of the silicon-based ceramic core blank are injection temperature 75-120° C., injection time 5-30 s, injection pressure 2-7.5 MPa, and holding time 30-60 s. In step six, the sintering parameters of the silicon-based ceramic core blank are sintering temperature of 1100-1250° C. and sintering time of 5-10 h.

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