Preparation method of novel ceramic filter for nickel-based superalloy melt pouring

Abstract

The embodiment of the invention discloses a preparation method of a novel ceramic filter for nickel-based superalloy melt pouring. The method comprises the following steps: S1, mixing Ca2Mg2Al28O46 raw material powder with a dispersing agent, a thickening agent, a binding agent and a burning promoting agent, and adding water for mixing to obtain raw material slurry; wherein in the raw material slurry, the content of a dispersing agent is 0.1 to 1.0 weight percent, the content of a thickening agent is 0.1 to 1.0 weight percent, the content of a binding agent is 0.5 to 3.0 weight percent, the content of a burning promoting agent is 5 to 15 weight percent, and the content of water is 20 to 40 weight percent; s2, the raw material slurry is subjected to multiple times of slurry hanging in a net-shaped porous template, and a green body is obtained; a three-dimensional communicated meshy hole structure is arranged in the meshy porous template; and S3, sintering the green body under set conditions to obtain the novel ceramic filter. The interior of the Ca2Mg2Al28O46-based novel ceramic filter is of a three-dimensional communicated mesh structure, the volume density is 0.3-0.8 g / cm < 3 >, the gas porosity is 70-90%, the normal-temperature compressive strength is 0.4-5.0 MPa, and the water-cooled thermal shock retention rate is 30-70% after heat preservation is conducted for 30 min at the temperature of 1100 DEG C.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature alloy preparation, and in particular relates to a method for preparing a novel ceramic filter for casting a nickel-based high-temperature alloy melt. Background Art

[0002] Excessive non-metallic inclusions in nickel-based superalloy melts can disrupt the matrix continuity of the alloy, significantly reducing its mechanical, corrosion-resistant, and high-temperature properties. Filtration technology, as the final step in alloy melt casting, effectively removes non-metallic inclusions from the melt, decisively impacting the quality of the final alloy product.

[0003] Current ceramic filter materials are primarily zirconia, silicon carbide, alumina, and calcia. Zirconia ceramic filters offer the advantages of high-temperature resistance, good chemical stability, high filtration efficiency, and the ability to effectively remove inclusions. However, they are relatively expensive, have limited thermal shock resistance, and may suffer structural damage from long-term use at high temperatures. Silicon carbide ceramic filters offer the advantages of high thermal conductivity, excellent thermal shock resistance, and high mechanical strength, but are susceptible to reaction with oxygen in the alloy melt, have limited resistance to high-temperature oxidation, and are relatively expensive. Alumina ceramic filters offer lower costs, a mature preparation process, and the ability to remove larger inclusions. However, their high-temperature resistance is relatively insufficient, they are susceptible to interfacial reactions with the alloy melt, and their filtration accuracy is limited. Calcium oxide ceramic filters have good chemical compatibility with the alloy melt and can effectively adsorb acidic inclusions, but are susceptible to hydrolysis, have poor high-temperature resistance, are susceptible to corrosion by the high-temperature melt, and have insufficient thermal shock resistance. Summary of the Invention

[0004] In view of this, some embodiments disclose a method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting, comprising the steps of:

[0005] S1, Ca2Mg2Al 28 O 46 The raw material powder is mixed with a dispersant, a thickener, a binder, and a sintering agent, and water is added to obtain a raw material slurry; wherein the raw material slurry has a dispersant content of 0.1 to 1.0 wt%, a thickener content of 0.1 to 1.0 wt%, a binder content of 0.5 to 3.0 wt%, a sintering agent content of 5 to 15 wt%, and a water content of 20 to 40 wt%;

[0006] S2, the raw material slurry is repeatedly coated in a mesh-like porous template to obtain a green body; the mesh-like porous template has a three-dimensional interconnected mesh pore structure;

[0007] S3. The green body is sintered under set conditions to obtain a new ceramic filter; the interior of the new ceramic filter has a three-dimensional interconnected mesh pore structure.

[0008] Furthermore, some embodiments disclose a method for preparing a new ceramic filter for casting nickel-based high-temperature alloy melt, wherein the dispersant is one of polycarboxylate, sodium citrate, and polyethylene glycol; the thickener is one of carboxymethyl cellulose and polyvinyl alcohol; the binder is one of ammonium lignin sulfonate, polyvinyl alcohol, and carboxymethyl cellulose; and the sintering promoter is one of aluminum sol, silica sol, and zirconium sol, with a solid content of 10 to 30 wt%.

[0009] Some embodiments disclose a method for preparing a novel ceramic filter for casting a nickel-based high-temperature alloy melt, wherein the mesh porous template is a polyurethane mesh porous template with a pore size of 9, 15 or 20 ppi.

[0010] In some embodiments, the method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting disclosed herein comprises the following steps:

[0011] The mesh porous template is immersed in the raw material slurry for a set time;

[0012] The mesh porous template impregnated with the raw material slurry is squeezed to squeeze out the excess raw material slurry, and a layer of raw material slurry is hung in the pore structure of the mesh porous template.

[0013] In some embodiments, the method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting disclosed herein comprises performing three slurry coating operations in a mesh-shaped porous template in step S2, specifically comprising:

[0014] First time slurrying:

[0015] The mesh porous template is immersed in the raw material slurry for a first set time;

[0016] The mesh porous template impregnated with the raw material slurry is squeezed by a double-roller machine to remove the excess raw material slurry and form a first layer of raw material slurry in the pore structure of the mesh porous template; the roller spacing of the double-roller machine is 8 to 20% of the thickness of the mesh porous template;

[0017] The mesh porous template with the first layer of raw material slurry is dried by blowing hot air at 40 to 60° C. for 1 to 5 minutes to obtain a first preform;

[0018] Second slurrying:

[0019] The first preform is immersed in the raw material slurry for a second set time;

[0020] The first preform impregnated with the raw material slurry is squeezed by a double-roller machine to squeeze out the excess raw material slurry, and a second layer of raw material slurry is hung in the pore structure of the mesh porous template; the roller spacing of the double-roller machine is 8 to 20% of the thickness of the mesh porous template;

[0021] The mesh porous template with the second layer of raw material slurry is dried by blowing hot air at 40 to 60° C. for 1 to 5 minutes to obtain a second preform;

[0022] The third slurry:

[0023] The second preform is immersed in the raw material slurry for a third set time;

[0024] The mesh porous template impregnated with the raw material slurry is squeezed by a double-roller machine to squeeze out the excess raw material slurry and hang a third layer of raw material slurry in the pore structure of the mesh porous template; the roller spacing of the double-roller machine is 8 to 20% of the thickness of the mesh porous template;

[0025] The mesh porous template with the third layer of raw material slurry is hung and naturally dried in the shade to obtain a green body.

[0026] Some embodiments disclose a method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting, further comprising pre-treating the mesh porous template, specifically comprising: soaking in a sodium hydroxide aqueous solution with a mass concentration of no more than 30% for a soaking time of no more than 120 minutes.

[0027] In some embodiments of the present invention, the method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting disclosed in step S3 specifically includes:

[0028] The green body is heated to 1450-1750° C. at a heating rate of 1-10° C. / min in an air atmosphere and kept at this temperature for 1-5 hours, and then cooled to obtain a novel ceramic filter.

[0029] In some embodiments of the present invention, the method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting disclosed in step S3 specifically includes:

[0030] The green body is heated to 300-700°C at a heating rate of 1-3°C / min in air atmosphere and kept warm for 1-2 hours, then heated to 1550-1700°C at a heating rate of 3-5°C / min and kept warm for 1-2 hours, and then cooled to obtain a new ceramic filter.

[0031] Some embodiments disclose a method for preparing a novel ceramic filter for casting a nickel-based high-temperature alloy melt, Ca2Mg2Al 28 O 46 The raw material powder is mixed with a dispersant, a thickener, a binder, and a sintering promoter, and stirred evenly at a stirring speed of 200 to 400 r / min and a stirring time of 4 to 5 minutes; water is added and further stirred evenly at a stirring speed of 800 to 1500 r / min and a stirring time of 20 to 30 minutes to obtain a raw material slurry.

[0032] On the other hand, some embodiments disclose a novel ceramic filter for casting a nickel-based high-temperature alloy melt, which is obtained by the preparation method of the novel ceramic filter for casting a nickel-based high-temperature alloy melt disclosed in the embodiment of the present invention. The novel ceramic filter has a three-dimensional interconnected network structure and a volume density of 0.3 to 0.8 g / cm 3 The porosity is 70-90%, the compressive strength at room temperature is 0.4-5.0 MPa, and the water-cooled thermal shock retention rate after 30 minutes of insulation at 1100°C is 30-70%.

[0033] The invention discloses a method for preparing a novel ceramic filter cast by a nickel-based high-temperature alloy melt, using Ca2Mg2Al 28 O 46 The raw material powder is prepared by one-step batching, multiple slurry coating process and one-step sintering method to prepare a new type of ceramic filter, which does not require multi-stage batching and secondary sintering, with simple process and low cost. 28 O 46 The new ceramic filter has high strength at room temperature, high porosity, low pressure drop, high surface roughness and specific surface area of ​​the pore skeleton, and excellent resistance to molten metal penetration and thermal shock. It can be used in molten metal filtration environments above 1300°C and has good application prospects in the field of nickel-based high-temperature alloy filtration. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Ca2Mg2Al prepared in Example 1 28 O 46 XRD pattern of the new ceramic filter;

[0035] Figure 2 Ca2Mg2Al prepared in Example 1 28 O 46 Digital photo of the new ceramic filter;

[0036] Figure 3 Ca2Mg2Al prepared in Example 1 28 O 46 SEM image of the surface of the new ceramic filter. DETAILED DESCRIPTION

[0037] The term "embodiment" is used herein specifically to describe any embodiment as "exemplary," and should not be construed as superior or preferable to other embodiments. Performance indicators in the embodiments of the present invention were tested using conventional testing methods in the art, unless otherwise specified. It should be understood that the terms used in the embodiments of the present invention are intended solely to describe specific implementations and are not intended to limit the disclosure of the embodiments of the present invention.

[0038] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the embodiments of the present invention pertain; any experimental methods and technical means not otherwise specified in the embodiments of the present invention refer to experimental methods and technical means commonly used by those skilled in the art.

[0039] As used herein, the terms "substantially" and "approximately" are used to describe small fluctuations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Numerical data expressed or presented in range format herein are used for convenience and brevity only and should therefore be interpreted flexibly to include not only the values ​​explicitly listed as the limits of the range, but also all independent values ​​or subranges contained within the range. For example, a numerical range of "1-5%" should be interpreted to include not only the explicitly listed values ​​of 1% to 5%, but also the independent values ​​and subranges within the indicated range. Thus, included in this numerical range are independent values ​​such as 2%, 3.5%, and 4%, and subranges such as 1% to 3%, 2% to 4%, and 3% to 5%, etc. This principle also applies to ranges that only list a single value. Furthermore, this interpretation applies regardless of the width of the range or the characteristics described.

[0040] Throughout this document, including in the claims, transitional terms such as "comprises," "includes," "with," "having," "contains," "involving," and "accommodating" are understood to be open-ended, meaning "including but not limited to." Only the transitional terms "consisting of" and "composed of" are closed transitional terms.

[0041] In order to better illustrate the present invention, numerous specific details are provided in the following specific examples. It should be understood by those skilled in the art that the present invention can be practiced without certain specific details. In the examples, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present invention.

[0042] Under the premise of no conflict, the technical features disclosed in the embodiments of the present invention can be arbitrarily combined, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present invention.

[0043] In some embodiments, a method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting comprises the steps of:

[0044] S1, Ca2Mg2Al 28 O 46The raw material powder is mixed with a dispersant, a thickener, a binder, and a sintering agent, and water is added to obtain a raw material slurry; wherein the raw material slurry has a dispersant content of 0.1 to 1.0 wt%, a thickener content of 0.1 to 1.0 wt%, a binder content of 0.5 to 3.0 wt%, a sintering agent content of 5 to 15 wt%, and a water content of 20 to 40 wt%;

[0045] Typically, Ca2Mg2Al 28 O 46 The raw material powder can be prepared according to the method disclosed in patent document CN119263852A; Ca2Mg2Al 28 O 46 Raw material powders usually need to be ground and powders of appropriate particle size are selected, such as Ca2Mg2Al 28 O 46 The particle size of the raw material powder is 0.5 to 100 μm.

[0046] In some embodiments, Ca2Mg2Al 28 O 46 The particle size of the raw material powder is less than 75 μm.

[0047] In some embodiments, Ca2Mg2Al 28 O 46 The particle size of the raw material powder is preferably D50=20 μm.

[0048] Typically, dispersants reduce the van der Waals attraction between raw powder particles through electrostatic repulsion or steric hindrance, preventing agglomeration and increasing the solids content of the slurry. Excessive dispersant addition can result in an excessively thick adsorption layer on the surface of the raw powder particles in the slurry, causing "reflocculation." Insufficient dispersant addition can lead to severe agglomeration of the raw powder particles in the slurry, a sharp increase in viscosity, and poor fluidity. In some embodiments, the dispersant is selected from the group consisting of polycarboxylates, sodium citrate, and polyethylene glycol.

[0049] In some embodiments, the content of the dispersant in the raw material slurry is 0.1-1.0 wt %.

[0050] In some embodiments, the preferred dispersant content is 0.2-0.5 wt %.

[0051] In some embodiments, the more preferred dispersant content is 0.3 wt %.

[0052] Generally, thickeners mainly increase the viscosity of the liquid phase or form a reversible network structure, so that the raw material slurry becomes thinner under shearing action and restores the viscosity after the shearing stops, which facilitates the control of the molding shape; adding too much thickener will make the slurry viscosity too high and the fluidity poor; while adding insufficient thickener will cause the slurry to be too thin, with weak thixotropy, and easy to flow during molding.

[0053] In some embodiments, the thickener is one of carboxymethyl cellulose and polyvinyl alcohol.

[0054] In some embodiments, the content of the thickener in the raw material slurry is 0.1-1.0 wt %.

[0055] In some embodiments, the preferred thickener content is 0.3-0.7 wt %.

[0056] In some embodiments, the more preferred thickener content is 0.5 wt %.

[0057] Typically, the binder forms a three-dimensional network during the drying process, imparting mechanical strength to the green body and preventing breakage during demolding or handling. Excessive amounts of binder can cause green body deformation, reduced sintered density, and reduced mechanical properties. Insufficient amounts of binder can result in low green body strength and brittleness after drying. In some embodiments, the binder is selected from the group consisting of ammonium lignin sulfonate, polyvinyl alcohol, and carboxymethyl cellulose.

[0058] In some embodiments, the content of the binder in the raw material slurry is 0.5-3.0 wt %.

[0059] In some embodiments, the preferred binder content is 0.8-1.5 wt %.

[0060] In some embodiments, a more preferred content of the binder is 1.0 wt %.

[0061] Typically, sintering promoters primarily reduce sintering temperature and improve densification by regulating liquid phase formation, lattice defects, or interfacial energy. Excessive addition of sintering promoters can increase the liquid phase, leading to green body deformation and decreased high-temperature strength. However, insufficient addition of sintering promoters can result in insufficient sintering driving force, weak intergranular bonding, and low product strength. In some embodiments, the sintering promoter is one of aluminum sol, silica sol, and zirconium sol, with a solids content of 10-30 wt%.

[0062] In some embodiments, the content of the sintering promoter is 5-15 wt %.

[0063] In some embodiments, the preferred content of the sintering promoter is 8-12 wt %.

[0064] In some embodiments, the more preferred content of the sintering promoter is 10 wt %.

[0065] In some embodiments, the water content in the raw material slurry is 20-40 wt %.

[0066] In some embodiments, the water content in the raw material slurry is preferably 25-34 wt %.

[0067] S2. The raw material slurry is repeatedly slurried in a reticulated porous template to obtain a green body; the reticulated porous template has a three-dimensional interconnected reticulated pore structure inside; generally, the internal structure and shape characteristics of the reticulated porous template determine the internal pore structure and shape of the new ceramic filter product, and a reticulated porous template that meets the needs can be designed according to the actual needs of the new ceramic filter; in some embodiments, the reticulated porous template is a polyurethane reticulated porous template with a pore size of 9, 15 or 20 ppi; wherein ppi stands for pores per inch, that is, the number of holes contained in each inch of the porous template sponge; the higher the ppi value, the smaller the pore size, and the lower the ppi value, the larger the pore size. For example, 9ppi means that there are 9 holes per inch of the template sponge.

[0068] Generally, the raw material slurry has a certain viscosity. During the process of impregnating the raw material slurry in the mesh porous template for slurry coating, a layer of raw material slurry will adhere to the surface of the internal pore structure of the template. If the number of slurry coating times is small and the amount of slurry coating is low, the green body will easily collapse during the sintering process. If the number of slurry coating times and the amount of slurry coating are large, the green body will cause serious pore blockage. Therefore, it is necessary to control the appropriate amount of slurry coating to obtain a new ceramic filter that meets the needs of use.

[0069] S3, the green body is sintered under set conditions to obtain a new ceramic filter; the interior of the new ceramic filter has a three-dimensional interconnected mesh pore structure. 28 O 46 The new ceramic filter has unique solid solution properties, with no free Al2O3 and MgO components. This effectively prevents the addition of oxygen to the alloy liquid, and upon contact with the alloy melt, slight dissolution occurs, releasing Ca ions. It can directly chemically adsorb Al2O3 inclusions without the need for a coating, and has the function of purifying the alloy melt, thereby improving the filtration efficiency of inclusions. Typically, during the sintering process of the green body, the mesh-like porous template body is burned away, forming the internal pore structure of the new ceramic filter. The raw material powder particles in the raw material slurry mounted on the internal structural wall of the green body adhere to each other, and gradually undergo material migration to form a densified, crystallized, integrated structural ceramic body. The structural strength of the ceramic body is increased, forming the ceramic structural body of the new ceramic filter.

[0070] In some embodiments, the method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting disclosed herein comprises the following steps:

[0071] The mesh porous template is immersed in the raw material slurry for a set time;

[0072] The mesh porous template impregnated with the raw material slurry is squeezed to squeeze out the excess raw material slurry, and a layer of raw material slurry is hung in the pore structure of the mesh porous template.

[0073] In some embodiments, the method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting disclosed herein comprises performing three slurry coating operations in a mesh-shaped porous template in step S2, specifically comprising:

[0074] The first slurry hanging: the mesh porous template is immersed in the raw material slurry for a first set time; the mesh porous template immersed in the raw material slurry is squeezed by a roller machine to squeeze out the excess raw material slurry and hang the first layer of raw material slurry in the pore structure of the mesh porous template; the mesh porous template with the first layer of raw material slurry is dried by hot air at 40-60°C for 1-5 minutes to obtain a first preform; usually, after the mesh porous template is immersed in the raw material slurry for a certain period of time, the raw material slurry fully enters the three-dimensional interconnected porous structure inside the template, and when the template is squeezed by the roller, the raw material slurry inside the template, which has a weaker bonding effect with the pore structure of the template, will come out of the template. The interior of the plate is squeezed out, and the excess raw material slurry is squeezed out, leaving an appropriate amount of raw material slurry in the pore structure inside the template to form a layer of raw material slurry film, thereby obtaining a first preform; the excess raw material slurry squeezed out is usually related to the distance between the rollers. The smaller the distance between the rollers, the more raw material slurry is squeezed out and the less raw material slurry remains inside the template; the appropriate roller distance is usually set according to the structural requirements of the new ceramic filter so as to leave an appropriate amount of raw material slurry in the pore structure inside the template. Generally, the roller spacing of the roller machine is controlled to be 8-20% of the thickness of the mesh porous template; in some embodiments, the more preferred roller spacing is 12% of the thickness of the mesh porous template;

[0075] Second slurry coating: the first preform is immersed in the raw material slurry for a second set time; the first preform immersed in the raw material slurry is squeezed by a double-roller machine to squeeze out the excess raw material slurry, and a second layer of raw material slurry is coated in the pore structure of the mesh porous template; the roller spacing of the double-roller machine is 8 to 20% of the thickness of the mesh porous template;

[0076] The mesh porous template with the second layer of raw material slurry is dried by blowing hot air at 40 to 60° C. for 1 to 5 minutes to obtain a second preform;

[0077] The third slurry:

[0078] The second preform is immersed in the raw material slurry for a third set time;

[0079] The mesh porous template impregnated with the raw material slurry is squeezed by a double-roller machine to squeeze out the excess raw material slurry and hang a third layer of raw material slurry in the pore structure of the mesh porous template; the roller spacing of the double-roller machine is 8 to 20% of the thickness of the mesh porous template;

[0080] The mesh porous template with the third layer of raw material slurry is hung and naturally dried in the shade to obtain a green body.

[0081] In some embodiments, the preferred roller spacing is 12% of the thickness of the porous mesh template.

[0082] Some embodiments disclose a method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting, further comprising pre-treating the mesh porous template, specifically comprising: soaking in a sodium hydroxide aqueous solution with a mass concentration of no more than 30% for a soaking time of no more than 120 minutes.

[0083] In some embodiments, the concentration of the sodium hydroxide aqueous solution is preferably 20%, and the soaking time is preferably 45 minutes.

[0084] In some embodiments of the present invention, the method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting disclosed in step S3 specifically includes:

[0085] The green body is heated to 1450-1750° C. at a heating rate of 1-10° C. / min in an air atmosphere and kept at this temperature for 1-5 hours, and then cooled to obtain a novel ceramic filter.

[0086] In some embodiments of the present invention, the method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting disclosed in step S3 specifically includes:

[0087] The green body is heated to 300-700°C at a heating rate of 1-3°C / min in air atmosphere and kept warm for 1-2 hours, then heated to 1550-1700°C at a heating rate of 3-5°C / min and kept warm for 1-2 hours, and then cooled to obtain a new ceramic filter.

[0088] Some embodiments disclose a method for preparing a novel ceramic filter for casting a nickel-based high-temperature alloy melt, Ca2Mg2Al 28 O 46 The raw material powder is mixed with a dispersant, a thickener, a binder and a sintering promoter, and stirred evenly for the first time at a stirring speed of 200 to 400 r / min and a stirring time of 4 to 5 minutes; water is added and stirred evenly for a second time at a stirring speed of 800 to 1500 r / min and a stirring time of 20 to 30 minutes to obtain a raw material slurry.

[0089] In some embodiments, the stirring speed for the first stirring is preferably 300 r / min, and the stirring time is preferably 5 min.

[0090] In some embodiments, the stirring speed for the second stirring is preferably 1000 r / min, and the stirring time is preferably 30 min.

[0091] Some embodiments disclose novel ceramic filters for casting nickel-based superalloy melts, obtained by the preparation method of the novel ceramic filter for casting nickel-based superalloy melts disclosed in the embodiments of the present invention. The novel ceramic filter has a three-dimensional interconnected network structure. Typically, the pores in the three-dimensional interconnected network structure within the novel porous ceramic are interconnected curved pores forming a network skeleton structure, with an open porosity of up to 80-90%. This filter can effectively remove large and microscopic suspended inclusions from the alloy liquid through mechanisms such as physical interception, deep adsorption, and scum rectification. It can be applied to the purification of inclusions in nickel-based superalloys, thereby reducing production costs and improving product performance.

[0092] The invention discloses a method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting, using Ca2Mg2Al 28 O 46 The new ceramic filter is prepared from raw material powder by adopting a one-step batching, multiple slurry coating process and one-step sintering method. It does not require multi-stage batching and secondary sintering, and the process is simple and the cost is low. The obtained new ceramic filter has a three-dimensional interconnected network structure and a volume density of 0.3-0.8g / cm 3 , the porosity is 70-90%, the compressive strength at room temperature is 0.4-5.0MPa, and the thermal shock retention rate after 1100℃ insulation for 30min is 30-70%; Ca2Mg2Al 28 O 46 The new ceramic filter has high strength at room temperature, high porosity, low pressure drop, high surface roughness and specific surface area of ​​the pore skeleton, and excellent resistance to molten metal penetration and thermal shock. It can be used in molten metal filtration environments above 1300°C and has good application prospects in the field of nickel-based high-temperature alloy filtration.

[0093] The technical details are further illustrated below with reference to embodiments.

[0094] Example 1

[0095] In Example 1, the preparation method of the novel ceramic filter for nickel-based high-temperature alloy melt casting includes:

[0096] S101, take 72 parts of the sieve undersize Ca2Mg2Al obtained by sieving with a 200 mesh sieve 28 O 46 The fine powder was added with 0.3 wt% of polycarboxylate, 0.5 wt% of carboxymethyl cellulose, 1.0 wt% of ammonium lignin sulfonate and 10 wt% of aluminum sol as the raw material slurry, and mechanically stirred and mixed at a speed of 300 r / min for 5 min to obtain powder A;

[0097] S102, adding 28 parts of water to powder A and continuing mechanical stirring at a speed of 1000 r / min, mixing for 30 minutes to obtain a raw material slurry;

[0098] S103, soaking the pretreated polyurethane mesh porous template in a 20% by mass NaOH solution for 45 minutes;

[0099] S104, after the raw material slurry is immersed in the pretreated polyurethane mesh porous template, the template is squeezed to remove air, allowing the slurry to be completely filled and fully coated; the slurry is squeezed using a double-roller machine, with the roller spacing being 12% of the height of the polyurethane mesh porous template; the surface is slightly dried using hot air at 40-60°C for 2-4 minutes to obtain a first preform;

[0100] S105, according to the process conditions of step S104, the first preform is again subjected to impregnation-squeezing-drying to obtain a second preform;

[0101] S106, referring to the process conditions of step S104, the second preform is impregnated and squeezed, and then naturally dried in the shade for 24 hours to obtain a green body;

[0102] S107, the obtained green body is heated from room temperature to 650℃ at 1℃ / min in air atmosphere and kept at this temperature for 1h, then heated to 1600℃ at 5℃ / min and kept at this temperature for 2h, and then cooled in the furnace to obtain the raw material powder Ca2Mg2Al 28 O 46 The new ceramic filter prepared is Ca2Mg2Al 28 O 46 New ceramic filter.

[0103] After testing, the Ca2Mg2Al prepared in Example 1 28 O 46 The volume density of the new ceramic filter is 0.51g / cm 3 , the porosity is 85%, the compressive strength at room temperature is 1.87MPa, and the thermal shock retention rate after 1100℃ insulation for 30min is 40.1%. Under the same test conditions, Ca2Mg2Al 28 O 46 The surface roughness of the new ceramic filter is Ra = 0.253 μm, and the surface roughness of the Al2O3 mesh porous ceramic is Ra = 0.100 μm.

[0104] Example 2

[0105] In Example 2, the preparation method of the novel ceramic filter for nickel-based high-temperature alloy melt casting includes:

[0106] S101, take 72 parts of the sieve undersize Ca2Mg2Al obtained by sieving with a 200 mesh sieve28 O 46 Add 0.3 wt% of polycarboxylate, 0.5 wt% of carboxymethyl cellulose, 1.0 wt% of ammonium lignin sulfonate and 10 wt% of silica sol to the raw material slurry, and mechanically stir and mix at a speed of 300 r / min for 5 min to obtain powder A;

[0107] S102, adding 28 parts of water to powder A and continuing mechanical stirring at a speed of 1000 r / min, mixing for 30 minutes to obtain a raw material slurry;

[0108] S103, soaking the pretreated polyurethane mesh porous template in a 20% by mass NaOH solution for 45 minutes;

[0109] S104, after the raw material slurry is immersed in the pretreated polyurethane mesh porous template, the template is squeezed to remove air, allowing the slurry to be completely filled and fully coated; the slurry is squeezed using a double-roller machine, with the roller spacing being 12% of the height of the polyurethane mesh porous template; the surface is slightly dried using hot air at 40-60°C for 2-4 minutes to obtain a first preform;

[0110] S105, according to the process conditions of step S104, the first preform is again subjected to impregnation-squeezing-drying to obtain a second preform;

[0111] S106, referring to the process conditions of step S104, the second preform is impregnated and squeezed, and then naturally dried in the shade for 24 hours to obtain a green body;

[0112] S107, the obtained green body is heated from room temperature to 650℃ at 1℃ / min in air atmosphere and kept at this temperature for 1h, then heated to 1600℃ at 5℃ / min and kept at this temperature for 2h, and then cooled in the furnace to obtain the raw material powder Ca2Mg2Al 28 O 46 The new ceramic filter prepared is Ca2Mg2Al 28 O 46 New ceramic filter.

[0113] After testing, the Ca2Mg2Al prepared in Example 2 28 O 46 The volume density of the new ceramic filter is 0.48g / cm 3 , the porosity is 78%, the compressive strength at room temperature is 1.51MPa, and the thermal shock retention rate after 1100℃ insulation for 30min is 37%. Under the same test conditions, Ca2Mg2Al 28 O 46 The surface roughness of the new ceramic filter is Ra = 0.201 μm, and the surface roughness of the Al2O3 mesh porous ceramic is Ra = 0.100 μm.

[0114] The invention discloses a method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting, using Ca2Mg2Al 28 O 46 The raw material powder is prepared by one-step batching, multiple slurry coating process and one-step sintering method to prepare a new type of ceramic filter, which does not require multi-stage batching and secondary sintering, with simple process and low cost. 28 O 46 The new ceramic filter has high strength at room temperature, high porosity, low pressure drop, high surface roughness and specific surface area of ​​the pore skeleton, and excellent resistance to molten metal penetration and thermal shock. It can be used in molten metal filtration environments above 1300°C and has good application prospects in the field of nickel-based high-temperature alloy filtration.

[0115] The technical solutions and technical details disclosed in the embodiments of the present invention are merely illustrative of the inventive concept of the present invention and do not constitute a limitation on the technical solutions of the embodiments of the present invention. Any conventional changes, replacements or combinations of the technical details disclosed in the embodiments of the present invention have the same inventive concept as the present invention and are within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a new ceramic filter for nickel-based high-temperature alloy melt casting, characterized in that: Including steps: S1, Ca2Mg2Al 28 O 46 The raw material powder is mixed with a dispersant, a thickener, a binder, and a sintering agent, and water is added to the mixture to obtain a raw material slurry; wherein the raw material slurry comprises 0.1 to 1.0 wt% of the dispersant, 0.1 to 1.0 wt% of the thickener, 0.5 to 3.0 wt% of the binder, 5 to 15 wt% of the sintering agent, and 20 to 40 wt% of the water; S2, the raw material slurry is repeatedly coated in a mesh-like porous template to obtain a green body; the mesh-like porous template has a three-dimensional interconnected mesh pore structure; S3. The green body is sintered under set conditions to obtain a novel ceramic filter; the novel ceramic filter has a three-dimensional interconnected mesh pore structure inside.

2. The method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting according to claim 1, characterized in that: The dispersant is one of polycarboxylate, sodium citrate, and polyethylene glycol; the thickener is one of carboxymethyl cellulose and polyvinyl alcohol; the binder is one of ammonium lignin sulfonate, polyvinyl alcohol, and carboxymethyl cellulose; the sintering promoter is one of aluminum sol, silica sol, and zirconium sol, with a solid content of 10 to 30 wt%.

3. The method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting according to claim 1, characterized in that: The mesh porous template is a polyurethane mesh porous template with a pore size of 9, 15 or 20 ppi.

4. The method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting according to claim 1, characterized in that: The process of slurrying the raw material in the mesh porous template includes: The mesh porous template is immersed in the raw material slurry for a set time; The mesh porous template impregnated with the raw material slurry is squeezed to squeeze out the excess raw material slurry, and a layer of raw material slurry is hung in the pore structure of the mesh porous template.

5. The method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting according to claim 4, characterized in that: In step S2, three slurry coatings are performed in the mesh porous template, specifically including: First time slurrying: The mesh porous template is immersed in the raw material slurry for a first set time; The mesh porous template impregnated with the raw material slurry is squeezed by a double-roller machine to remove the excess raw material slurry and hang a first layer of raw material slurry in the pore structure of the mesh porous template; the roller spacing of the double-roller machine is 8 to 20% of the thickness of the mesh porous template; The mesh porous template with the first layer of raw material slurry is dried by blowing hot air at 40 to 60° C. for 1 to 5 minutes to obtain a first preform; Second slurrying: The first preform is immersed in the raw material slurry for a second set time; The first preform impregnated with the raw material slurry is squeezed by a double-roller machine to squeeze out the excess raw material slurry, and a second layer of raw material slurry is hung in the pore structure of the mesh porous template; the roller spacing of the double-roller machine is 8 to 20% of the thickness of the mesh porous template; The mesh porous template with the second layer of raw material slurry is dried by blowing hot air at 40 to 60° C. for 1 to 5 minutes to obtain a second preform; The third slurry: The second preform is immersed in the raw material slurry for a third set time; The mesh porous template impregnated with the raw material slurry is squeezed by a double-roller machine to squeeze out the excess raw material slurry and hang a third layer of raw material slurry in the pore structure of the mesh porous template; the roller spacing of the double-roller machine is 8 to 20% of the thickness of the mesh porous template; The mesh porous template with the third layer of raw material slurry is hung and naturally dried in the shade to obtain a green body.

6. The method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting according to claim 4, characterized in that: The method further includes pre-treating the mesh porous template, specifically including: soaking in a sodium hydroxide aqueous solution with a mass concentration of no more than 30% for a soaking time of no more than 120 minutes.

7. The method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting according to claim 1, characterized in that: Step S3 specifically includes: The green body is heated to 1450-1750° C. at a heating rate of 1-10° C. / min in an air atmosphere and kept at this temperature for 1-5 hours, and then cooled to obtain a novel ceramic filter.

8. The method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting according to claim 1, characterized in that: Step S3 specifically includes: The green body is heated to 300-700°C at a heating rate of 1-3°C / min in air atmosphere and kept warm for 1-2 hours, then heated to 1550-1700°C at a heating rate of 3-5°C / min and kept warm for 1-2 hours, and then cooled to obtain a new ceramic filter.

9. The method for preparing a novel ceramic filter for nickel-based high-temperature alloy melt casting according to claim 1, characterized in that: Ca2Mg2Al 28 O 46 The raw material powder is mixed with a dispersant, a thickener, a binder, and a sintering promoter, and stirred evenly at a stirring speed of 200 to 400 r / min and a stirring time of 4 to 5 minutes; water is added and further stirred evenly at a stirring speed of 800 to 1500 r / min and a stirring time of 20 to 30 minutes to obtain a raw material slurry.

10. A new type of ceramic filter for nickel-based high-temperature alloy melt casting, characterized in that: The novel ceramic filter is obtained by the preparation method according to any one of claims 1 to 9, and has a three-dimensional interconnected network structure and a volume density of 0.3 to 0.8 g / cm 3 The porosity is 70-90%, the compressive strength at room temperature is 0.4-5.0 MPa, and the water-cooled thermal shock retention rate after 30 minutes of insulation at 1100°C is 30-70%.

Images