CN112408989A - Silicon nitride powder pretreatment and low-defect blank injection molding method - Google Patents
Silicon nitride powder pretreatment and low-defect blank injection molding method Download PDFInfo
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Abstract
The invention relates to a silicon nitride powder pretreatment and low-defect blank injection molding method. On one hand, a small amount of free silicon contained in the commercially available silicon nitride powder is completely eliminated by a simple silicon nitride powder pretreatment method, and the problem of the air hole defect in the injection molding silicon nitride ceramic blank is effectively solved; on the other hand, the dispersion characteristic of the silicon nitride powder in water is obviously improved, and then the high-performance silicon nitride water-based slurry is prepared. The pretreated silicon nitride powder is subjected to injection molding to obtain a low-defect ceramic blank with a uniform apparent tissue structure. The injection molding method of the invention utilizes the physical characteristics of the hot melt adhesive of the natural macromolecular gel polymer to replace the traditional acrylamide monomer cross-linking polymerization to realize the gel solidification of the ceramic slurry, and has the advantages of no toxicity, environmental protection, strong process controllability, less organic matter consumption, no need of independent degreasing and the like. The invention provides a preparation method of high-performance silicon nitride ceramics by injection molding, which has simple process, is convenient for industrial production and has great popularization value.
Description
Technical Field
The invention relates to silicon nitride powder and a ceramic material thereof, in particular to a pretreatment method of the silicon nitride powder, the obtained silicon nitride powder and a low-defect ceramic blank injection molding method thereof.
Background
The silicon nitride ceramic material has high atomic bonding strength, extremely high temperature resistance, high strength which can be maintained to 1200 ℃ without reduction, can not be melted into a melt after being heated, can not be decomposed until 1900 ℃, has remarkable chemical corrosion resistance, can resist almost all inorganic acids and caustic soda solution with the concentration of less than 30 percent, and can resist corrosion of a plurality of organic acids; meanwhile, the ceramic material has stable dielectric property and is one of the ceramic materials with the best comprehensive property.
In-situ gel casting is an effective method for forming ceramic blanks with large size, complex shape and high uniformity in near net size, has the remarkable advantages of high blank strength, uniform microstructure, low organic matter content and the like compared with the traditional wet forming processes such as grouting, injection, pressure pouring and the like, and is widely applied to various oxide ceramics. However, there are still many problems to be solved in the preparation of high-performance ceramic slurry, the control of gelation uniformity, the control of ceramic body defects, and the like, for non-oxide ceramics with hydrophobicity and hydrolyzability such as silicon nitride. For example, the silicon nitride ceramic body prepared by injection molding method using commercially available silicon nitride powder is easy to generate the air hole defect shown in fig. 1, and the product quality is seriously influenced.
Disclosure of Invention
In order to solve the above technical problems, the present invention aims to provide a method for pretreating silicon nitride powder, the obtained silicon nitride powder and a method for injection molding of a low-defect ceramic blank thereof.
According to one aspect of the present invention, there is provided a method for pretreating silicon nitride powder, comprising the steps of:
mixing silicon nitride with an alkaline aqueous solution to obtain slurry;
and heating, soaking and drying the slurry to obtain the pretreated silicon nitride powder.
Further, the pH value of the alkaline aqueous solution is 9-10, and the silicon nitride powder accounts for 10-25% of the volume fraction of the slurry.
Further, the heating temperature is 60-100 ℃, the heating mode is water bath heating, and the heating soaking time is 4-24 h.
Further, the alkaline aqueous solution is one or more of tetramethylammonium hydroxide, ethylammonium hydroxide, propylammonium hydroxide and butylammonium hydroxide.
According to another aspect of the present invention, there is provided a pretreated silicon nitride powder, prepared by any one of the above methods, wherein the silicon nitride powder is free of free silicon and the surface of the powder is coated with a silicon oxide layer. The silicon nitride powder prepared by the current commercial silicon powder nitriding method generally contains a small amount of free silicon, the initial free silicon content is not more than 1 percent, the existence of the free silicon is easy to cause the problem of air hole defects in a blank body of a silicon nitride ceramic material in the later period of injection molding, the pretreatment completely eliminates the small amount of free silicon in the obtained silicon nitride powder, effectively solves the problem of air hole defects in the silicon nitride ceramic blank body of injection molding, can form a silicon oxide coating layer on the surface of the silicon nitride powder, and obviously improves the dispersion characteristic of the silicon nitride powder in water.
According to another aspect of the present invention, there is provided a method of gel injection molding a low defect ceramic body, comprising the steps of:
(1) dissolving a dispersing agent in deionized water to prepare a premixed solution with a certain solubility;
further, the dispersant is one or more of ammonium citrate, triethanolamine, ammonium polyacrylate and tetramethylammonium hydroxide.
(2) Ball milling and mixing the pretreated silicon nitride powder and the sintering aid in the premixed liquid to prepare ceramic slurry, heating in a water bath, preserving heat, and continuously stirring;
furthermore, the ceramic powder solid phase volume fraction in the ceramic slurry is 45-55%, the dispersant accounts for 0.5-3.0% of the mass of the ceramic powder, the sintering aid is one or more of silicon dioxide, aluminum oxide, magnesium oxide, tin oxide, lanthanum oxide and strontium oxide, and the water bath temperature is 40-80 ℃.
(3) Dissolving a natural macromolecular gel polymer with the physical characteristics of a hot melt adhesive in deionized water, heating in a water bath, and dissolving to obtain a polymer solution;
furthermore, the natural macromolecular gel polymer is one of agarose, gelatin, pectin, agar or carrageenan, the water bath temperature is 60-100 ℃, and the polymer solution solubility is 10-20%.
(4) Adding the polymer solution into the ceramic slurry heated and insulated in water bath, stirring until the mixture is uniformly mixed, and performing vacuum stirring and degassing to obtain injection molding slurry;
furthermore, the natural macromolecular gel polymer in the injection molding slurry accounts for 0.3-1.5% of the mass of the ceramic powder.
(5) Injecting the injection molding slurry into a preheated forming mold, and curing and forming at normal temperature or low temperature to obtain a ceramic blank;
further, the curing temperature is 0-30 ℃.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the pretreatment method of the silicon nitride powder and the pretreated silicon nitride powder product, disclosed by the invention, a reaction is generated between the silicon nitride powder and an alkaline aqueous solution, so that a small amount of free silicon contained in the silicon nitride powder is completely eliminated by the reaction, and a silicon oxide coating layer is formed on the surface of the silicon nitride powder. Compared with the commercial silicon nitride powder, the silicon nitride powder after pretreatment can effectively solve the problem of air hole defects in the silicon nitride ceramic blank formed by injection molding, and simultaneously, the dispersion characteristic of the silicon nitride powder in water is obviously improved, so that the high-performance silicon nitride water-based slurry is prepared.
2. According to the injection molding method of the low-defect ceramic body, silicon nitride powder after simple pretreatment is adopted, the problem that the commercially available silicon nitride powder is easy to generate air hole defects in the injection molded body is effectively solved, as shown in figure 2, the obtained ceramic body is homogeneous in appearance and free of defects, and the method is low in cost, good in repeatability and convenient for industrial production; the forming method of the invention utilizes the physical characteristics of the hot melt adhesive of the natural macromolecular gel polymer to replace the traditional acrylamide monomer cross-linking polymerization to realize the gel solidification of the ceramic slurry, has the advantages of no toxicity, environmental protection, strong process controllability, less organic matter consumption, no need of independent degreasing and the like, and has great popularization value.
Drawings
FIG. 1 is a picture of a ceramic body obtained by injection molding commercially available silicon nitride powder;
FIG. 2 is a picture of a ceramic blank obtained by injection molding of pretreated silicon nitride powder.
Detailed Description
In order to better understand the technical scheme of the invention, the invention is further explained by combining the drawings and the specific embodiments in the specification.
The first embodiment is as follows:
the embodiment provides a pretreatment method of silicon nitride powder, which comprises the following steps:
s1, mixing silicon nitride powder with an alkaline aqueous solution to obtain slurry, wherein the pH of the alkaline aqueous solution is 9-10, and the silicon nitride powder accounts for 10% of the volume of the slurry;
the alkaline aqueous solution is an aqueous solution of tetramethylammonium hydroxide.
And S2, heating, soaking and drying the slurry to obtain pretreated silicon nitride powder, wherein the heating temperature is 70-75 ℃, the heating mode is water bath heating, and the heating soaking time is 24 hours.
The pretreatment process of the silicon nitride powder comprises the following specific steps:
(1) mechanically stirring and uniformly mixing silicon nitride powder and a tetramethylammonium hydroxide aqueous solution with the pH value of 9-10 to prepare slurry, wherein the silicon nitride powder accounts for 10% of the volume of the slurry;
(2) carrying out water bath treatment on the slurry at 70-75 ℃, heating and soaking for 24h, and carrying out the following reaction between silicon nitride powder and an alkaline aqueous solution, wherein on one hand, a small amount of free silicon contained in the silicon nitride powder is completely eliminated by reaction, and on the other hand, a silicon oxide coating layer is formed on the surface of the silicon nitride powder;
Si3N4+6H2O→3SiO2+4NH3↑
Si3N4+6S2O8 2-+12OH-→3SiO2+2N2↑+12SO4 2-+6H2O
Si+4H2O→H4SiO4+2H2↑
(3) drying the slurry at 70-100 ℃ to obtain pretreated silicon nitride powder;
this example provides a pretreated silicon nitride powder, in which the residual free silicon in the powder is completely eliminated by reaction, and an oxide coating layer is formed on the surface of the powder, and the oxygen content of the silicon nitride powder is 5 wt%.
The embodiment provides a gel injection molding method of a low-defect ceramic body, which comprises the following steps:
(1) dissolving a dispersing agent in deionized water to prepare a premixed solution with a certain solubility;
the dispersant is ammonium citrate.
(2) Ball milling and mixing the pretreated silicon nitride powder and the sintering aid in the premixed liquid to prepare ceramic slurry, heating in a water bath, preserving heat, and continuously stirring;
the volume fraction of the solid phase of the ceramic powder in the ceramic slurry is 45%, the dispersant accounts for 2.0% of the mass of the ceramic powder, the sintering aid is preferably silicon dioxide and lanthanum oxide, and the water bath temperature is 60-65 ℃.
(3) Dissolving a natural macromolecular gel polymer with the physical characteristics of a hot melt adhesive in deionized water, heating in a water bath, and dissolving to obtain a polymer solution;
the natural macromolecular gel polymer is agarose, the water bath temperature is 90-95 ℃, and the solubility of the polymer solution is 15%.
(4) Adding the polymer solution into the ceramic slurry heated and insulated in water bath, stirring until the mixture is uniformly mixed, and performing vacuum stirring and degassing to obtain injection molding slurry;
agarose in the injection molding slurry accounts for 1.0 percent of the mass of the ceramic powder, and the vacuum stirring degassing time is 30 min;
(5) injecting the injection molding slurry into a molding die preheated at 50 ℃, and curing and molding at normal temperature or low temperature to obtain a ceramic blank;
the curing temperature is 20-25 ℃.
The gel injection molding process of the low-defect ceramic body comprises the following specific steps:
(1) ceramic slurry preparation
Dissolving a proper amount of ammonium citrate in a certain amount of deionized water to prepare a premixed solution; ball-milling and mixing the premixed liquid with pretreated silicon nitride powder, sintering aid and other ceramic powder for 12 hours to prepare ceramic slurry, wherein the solid-phase volume fraction of the ceramic powder in the ceramic slurry is 45%, and the mass of ammonium citrate is 2.0% of that of the ceramic powder;
heating the ceramic slurry in water bath at 60-65 deg.C, sealing, and mechanically stirring.
(2) Injection molding slurry preparation
Adding agarose into deionized water, heating in water bath at 90-95 deg.C for 30min to dissolve, and preparing 15% solubility polymer solution;
adding the agarose solution into the ceramic slurry heated and insulated by the water bath in the step (1), sealing, mechanically stirring for 5min, uniformly mixing, and carrying out vacuum stirring and degassing for 30min to obtain injection molding slurry, wherein the agarose in the injection molding slurry is 1.0 percent of the mass of the ceramic powder;
(3) injection molding and curing
Injecting the injection molding slurry into a preheated metal mold at 50 ℃, and curing and molding at the room temperature of 20-25 ℃ to obtain a low-defect ceramic blank with certain strength and slight elasticity.
Example two:
the embodiment provides a pretreatment method of silicon nitride powder, which comprises the following steps:
s1, mixing silicon nitride powder with an alkaline aqueous solution to obtain slurry, wherein the pH of the alkaline aqueous solution is 9-10, and the silicon nitride powder accounts for 25% of the volume of the slurry;
the alkaline aqueous solution is an aqueous solution of propyl ammonium hydroxide.
And S2, heating, soaking and drying the slurry to obtain pretreated silicon nitride powder, wherein the heating temperature is 90-95 ℃, the heating mode is water bath heating, and the heating soaking time is 12 hours.
The pretreatment process of the silicon nitride powder comprises the following specific steps:
(1) mechanically stirring and uniformly mixing silicon nitride powder and a water solution of propyl ammonium hydroxide with the pH value of 9-10 to prepare slurry, wherein the silicon nitride powder accounts for 25% of the volume of the slurry;
(2) treating the slurry in water bath at 90-95 ℃, heating and soaking for 12h, and reacting the silicon nitride powder with alkaline aqueous solution to completely eliminate a small amount of free silicon contained in the silicon nitride powder and form a silicon oxide coating layer on the surface of the silicon nitride powder;
Si3N4+6H2O→3SiO2+4NH3↑
Si3N4+6S2O8 2-+12OH-→3SiO2+2N2↑+12SO4 2-+6H2O
Si+4H2O→H4SiO4+2H2↑
(3) drying the slurry at 70-100 ℃ to obtain pretreated silicon nitride powder;
this example provides a pretreated silicon nitride powder, in which the residual free silicon in the powder is completely eliminated by reaction, and an oxide coating layer is formed on the surface of the powder, and the oxygen content of the silicon nitride powder is 8 wt%.
The embodiment provides a gel injection molding method of a low-defect ceramic body, which comprises the following steps:
(1) dissolving a dispersing agent in deionized water to prepare a premixed solution with a certain solubility;
the dispersant is ammonium polyacrylate.
(2) Ball milling and mixing the pretreated silicon nitride powder and the sintering aid in the premixed liquid to prepare ceramic slurry, heating in a water bath, preserving heat, and continuously stirring;
the ceramic powder solid volume fraction in the ceramic slurry is 54%, the dispersant is 1.0% of the ceramic powder mass, the sintering aid is preferably alumina and magnesia, and the water bath temperature is 40-45 ℃.
(3) Dissolving a natural macromolecular gel polymer with the physical characteristics of a hot melt adhesive in deionized water, heating in a water bath, and dissolving to obtain a polymer solution;
the natural macromolecular gel polymer is gelatin, the water bath temperature is 60-65 ℃, and the solubility of the polymer solution is 10%.
(4) Adding the polymer solution into the ceramic slurry heated and insulated in water bath, stirring until the mixture is uniformly mixed, and performing vacuum stirring and degassing to obtain injection molding slurry;
gelatin in the injection molding slurry accounts for 1.5% of the mass of the ceramic powder, and the vacuum stirring degassing time is 40 min;
(5) injecting the injection molding slurry into a preheating molding die at 30 ℃, and curing and molding at normal temperature or low temperature to obtain a ceramic blank;
the curing temperature is 10-15 ℃.
The gel injection molding process of the low-defect ceramic body comprises the following specific steps:
(1) ceramic slurry preparation
Dissolving a proper amount of ammonium citrate in a certain amount of deionized water to prepare a premixed solution; ball-milling and mixing the premixed liquid with pretreated silicon nitride powder, sintering aid and other ceramic powder for 12 hours to prepare ceramic slurry, wherein the solid-phase volume fraction of the ceramic powder in the ceramic slurry is 54%, and the mass of ammonium polyacrylate in the ceramic slurry is 1.0% of that of the ceramic powder;
heating the ceramic slurry in 40-45 deg.C water bath, sealing, and mechanically stirring.
(2) Injection molding slurry preparation
Adding gelatin into deionized water, heating in water bath at 60-65 deg.C for 30min to dissolve, and preparing 10% solubility polymer solution;
adding gelatin solution into the ceramic slurry heated and insulated by the water bath in the step (1), sealing, mechanically stirring for 5min, uniformly mixing, and carrying out vacuum stirring and degassing for 40min to obtain injection molding slurry, wherein the mass of agarose in the injection molding slurry is 1.5% of that of the ceramic powder;
(3) injection molding and curing
And injecting the injection molding slurry into a preheated metal mold at the temperature of 30 ℃, and curing and molding at the room temperature of 10-15 ℃ to obtain a low-defect ceramic blank with higher strength and slight elasticity.
Example three:
the embodiment provides a pretreatment method of silicon nitride powder, which comprises the following steps:
s1, mixing silicon nitride powder with an alkaline aqueous solution to obtain slurry, wherein the pH of the alkaline aqueous solution is 9-10, and the silicon nitride powder accounts for 20% of the volume of the slurry;
the alkaline aqueous solution is an aqueous solution of ethyl ammonium hydroxide.
And S2, heating, soaking and drying the slurry to obtain pretreated silicon nitride powder, wherein the heating temperature is 80-85 ℃, the heating mode is water bath heating, and the heating soaking time is 18 h.
The pretreatment process of the silicon nitride powder comprises the following specific steps:
(1) mechanically stirring and uniformly mixing silicon nitride powder and an aqueous solution of ethyl ammonium hydroxide with the pH value of 9-10 to prepare slurry, wherein the silicon nitride powder accounts for 20% of the volume of the slurry;
(2) treating the slurry in water bath at 80-85 ℃, heating and soaking for 18h, and reacting the silicon nitride powder with alkaline aqueous solution to completely eliminate a small amount of free silicon contained in the silicon nitride powder and form a silicon oxide coating layer on the surface of the silicon nitride powder;
Si3N4+6H2O→3SiO2+4NH3↑
Si3N4+6S2O8 2-+12OH-→3SiO2+2N2↑+12SO4 2-+6H2O
Si+4H2O→H4SiO4+2H2↑
(3) drying the slurry at 70-100 ℃ to obtain pretreated silicon nitride powder;
this example provides a pretreated silicon nitride powder, in which the residual free silicon in the powder is completely eliminated by reaction, and an oxide coating layer is formed on the surface of the powder, and the oxygen content of the silicon nitride powder is 6 wt%.
The embodiment provides a gel injection molding method of a low-defect ceramic body, which comprises the following steps:
(1) dissolving a dispersing agent in deionized water to prepare a premixed solution with a certain solubility;
the dispersing agent is ammonium polyacrylate and tetramethyl ammonium hydroxide.
(2) Ball milling and mixing the pretreated silicon nitride powder and the sintering aid in the premixed liquid to prepare ceramic slurry, heating in a water bath, preserving heat, and continuously stirring;
the ceramic powder solid phase volume fraction in the ceramic slurry is 48%, the dispersant accounts for 1.2% of the mass of the ceramic powder, the sintering aid is preferably lanthanum oxide and strontium oxide, and the water bath temperature is 50-55 ℃.
(3) Dissolving a natural macromolecular gel polymer with the physical characteristics of a hot melt adhesive in deionized water, heating in a water bath, and dissolving to obtain a polymer solution;
the natural macromolecular gel polymer is agar, the water bath temperature is 85-90 ℃, and the solubility of the polymer solution is 10%.
(4) Adding the polymer solution into the ceramic slurry heated and insulated in water bath, stirring until the mixture is uniformly mixed, and performing vacuum stirring and degassing to obtain injection molding slurry;
the agar in the injection molding slurry accounts for 0.5 percent of the mass of the ceramic powder, and the vacuum stirring degassing time is 35 min;
(5) injecting the injection molding slurry into a preheating molding die at 45 ℃, and curing and molding at normal temperature or low temperature to obtain a ceramic blank;
the curing temperature is 15-20 ℃.
The gel injection molding process of the low-defect ceramic body comprises the following specific steps:
(1) ceramic slurry preparation
Dissolving a proper amount of ammonium polyacrylate and tetramethylammonium hydroxide in a certain amount of deionized water to prepare a premixed solution; ball-milling and mixing the premixed liquid with pretreated silicon nitride powder, sintering aid and other ceramic powder for 12 hours to prepare ceramic slurry, wherein the solid phase volume fraction of the ceramic powder in the ceramic slurry is 48%, and the mass of ammonium polyacrylate and tetramethylammonium hydroxide is 1.2% of that of the ceramic powder;
heating the ceramic slurry in 50-55 deg.C water bath, sealing, and mechanically stirring.
(2) Injection molding slurry preparation
Adding agar into deionized water, heating in water bath at 85-90 deg.C for 30min to dissolve, and preparing 10% solubility polymer solution;
adding the agar solution into the ceramic slurry heated and insulated by the water bath in the step (1), sealing, mechanically stirring for 5min, uniformly mixing, and carrying out vacuum stirring and degassing for 35min to obtain injection molding slurry, wherein the mass of agarose in the injection molding slurry is 0.5% of that of the ceramic powder;
(3) injection molding and curing
Injecting the injection molding slurry into a metal mold preheated at 45 ℃, and curing and molding at the room temperature of 15-20 ℃ to obtain a low-defect ceramic blank with certain strength and certain elasticity.
Example four:
FIG. 1 is a picture of a ceramic body obtained by injection molding;
FIG. 2 is a picture of a ceramic blank obtained by injection molding of pretreated silicon nitride powder.
The picture of the ceramic body obtained by adopting the commercial silicon nitride powder to perform injection molding is compared with the picture of the ceramic body obtained by adopting the silicon nitride powder which is subjected to simple pretreatment to perform injection molding in the embodiment:
as can be seen from fig. 1, the ceramic body obtained by injection molding of commercially available silicon nitride powder has a large number of pore defects, which are obvious.
As can be seen from FIG. 2, the ceramic blank obtained by injection molding of the silicon nitride powder after simple pretreatment has a uniform apparent structure and no problem of macroscopic pore defects, and has an obvious effect compared with FIG. 1.
The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.
Claims (10)
1. A pretreatment method of silicon nitride powder is characterized by comprising the following steps:
mixing silicon nitride with an alkaline aqueous solution to obtain slurry;
and heating, soaking and drying the slurry to obtain the pretreated silicon nitride powder.
2. The method for pretreating silicon nitride powder according to claim 1, wherein the pH of the alkaline aqueous solution is 9 to 10, and the silicon nitride powder accounts for 10 to 25 volume percent of the slurry.
3. The method for pretreating silicon nitride powder according to claim 1, wherein the heating temperature is 60-100 ℃, the heating mode is water bath heating, and the heating soaking time is 4-24 h.
4. The method for pretreating a silicon nitride powder according to any one of claims 1 to 3, wherein the alkaline aqueous solution is an aqueous solution of one or more of tetramethylammonium hydroxide, ethylammonium hydroxide, propylammonium hydroxide, and butylammonium hydroxide.
5. A pretreated silicon nitride powder, characterized in that it is obtained by the process according to any one of claims 1 to 4, the silicon nitride powder obtained has no free silicon therein and the surface of the powder is coated with a silicon oxide layer.
6. A method for injection molding a low defect green body, comprising the steps of:
(1) dissolving a dispersing agent in deionized water to prepare a premixed solution with a certain solubility;
(2) ball milling and mixing the pretreated silicon nitride powder and the sintering aid in the pre-mixed liquid according to claim 5 to prepare ceramic slurry, heating in a water bath, keeping the temperature, and continuously stirring;
(3) dissolving a natural macromolecular gel polymer with the physical characteristics of a hot melt adhesive in deionized water, heating in a water bath, and dissolving to obtain a polymer solution;
(4) adding the polymer solution into the ceramic slurry heated and insulated in water bath, stirring until the mixture is uniformly mixed, and performing vacuum stirring and degassing to obtain injection molding slurry;
(5) and injecting the injection molding slurry into a preheated forming mold, and curing and forming at normal temperature or low temperature to obtain a ceramic blank.
7. The method of claim 6, wherein the dispersant of step (1) is one or more of ammonium citrate, triethanolamine, ammonium polyacrylate, and tetramethylammonium hydroxide.
8. The injection molding method of a low-defect ceramic body according to claim 6, wherein the ceramic slurry in the step (2) has a solid phase volume fraction of 45-55% of ceramic powder, a dispersant of 0.5-3.0% of the mass of the ceramic powder, a sintering aid of one or more of silica, alumina, magnesia, tin oxide, lanthanum oxide and strontium oxide, and a water bath temperature of 40-80 ℃.
9. The injection molding method of a low-defect ceramic body according to claim 6, wherein the natural macromolecular gel polymer of step (3) is one of agarose, gelatin, pectin, agar or carrageenan, the water bath temperature is 80-100 ℃, and the polymer solution solubility is 10-20%.
10. The method for injection molding of a ceramic body with low defects according to claim 6, wherein the natural macromolecular gel polymer in the injection molding slurry of step (4) is 0.3 to 1.5% by mass of the ceramic powder, and the curing temperature of step (5) is 0 to 30 ℃.
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