A binder for forming a BJ silicon carbide ceramic and a preparation method and application thereof

Abstract

The application discloses a kind of BJ silicon carbide ceramic forming binder and its preparation method and application, belong to binder spray forming technical field.The binder includes the following weight parts of raw materials: glycerol 70-90 parts, silane coupling agent 30-50 parts and ethylenediamine 2-5 parts, and solvent 1, solvent 2 and solvent 3;Preparation method: (1) weigh each raw material;(2) preparation solvent 1;(3) preparation solvent 2;(4) preparation solvent 3;(5) solvent 3 is added to solvent 2, stirring cooling, add solvent 1, heating, heat preservation stirring, add ethylenediamine, heat preservation stirring, add silane coupling agent, heat preservation stirring, add glycerol, heat preservation stirring, cooling to room temperature, obtain.The binder of the application can be used for BJ silicon carbide ceramic forming, with high purity, high carbon content and high bonding strength and the like, and simplify process steps, reduce production cost, provide high-quality, high-efficiency silicon carbide ceramic parts for industrial application.

Description

Technical Field

[0001] This invention relates to the field of binder spray molding technology, and more specifically to a binder for molding BJ silicon carbide ceramics, its preparation method, and its application. Background Technology

[0002] In recent years, with the rapid development of science and technology, high-performance ceramics need to meet the requirements of large-size and complex configurations under specific environments. Silicon carbide (SiC) ceramics, as an important thermal structural material, possess unique and excellent properties such as high strength and hardness, good chemical stability, and high thermal conductivity, and are widely used in engineering fields such as aerospace, space exploration, and energy and chemical engineering. However, the traditional forming process for preparing high-performance fine ceramics is difficult to achieve complex, irregularly shaped forming of porous thin-walled structures such as honeycomb and topological structures, resulting in limitations such as long preparation cycles, high production costs, and poor processability, which seriously restricts the further promotion and application of silicon carbide ceramics. The new binder jetting (BJ) forming technology can effectively solve these problems and provide a new solution for the preparation of high-performance ceramics.

[0003] Using BJ to print blanks requires a high-performance binder. Considering factors such as the compatibility, temperature resistance, curing shrinkage, and coefficient of thermal expansion of the binder with silicon carbide ceramics, the binder needs to have excellent adhesion and stability in order to increase the carbon content in the blank, improve the density of the blank, enhance the bonding quality and dimensional stability of the parts, and improve the sintering mechanical properties of silicon carbide ceramics.

[0004] Therefore, how to develop a high-performance binder for molding BJ silicon carbide ceramics is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a binder for molding BJ silicon carbide ceramics, its preparation method and application, so as to overcome the shortcomings of the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A binder for molding BJ silicon carbide ceramics comprises the following raw materials in parts by weight: 70-90 parts glycerol, 30-50 parts silane coupling agent and 2-5 parts ethylenediamine, as well as solvent 1, solvent 2 and solvent 3;

[0008] Solvent 1 comprises the following raw materials in parts by weight: 75-100 parts of ethanol, 50-100 parts of phenolic resin, and 30-60 parts of ethylene glycol or propanol.

[0009] Solvent 2 comprises the following raw materials in parts by weight: 100-150 parts furfuryl alcohol, 10-20 parts formic acid or propionic acid, 5-10 parts urea, 2-5 parts paraformaldehyde (first part), 1-3 parts hydrochloric acid, and 1-2 parts paraformaldehyde (second part).

[0010] Solvent 3 comprises the following raw materials in parts by weight: 50-70 parts furfuryl alcohol and 20-50 parts butyl acetate.

[0011] Furthermore, the aforementioned glycerol is at least one of diglycerol, triglycerol, and pentaglycerol.

[0012] The further beneficial effects of the above-mentioned method are that the glycerin selected in this invention can increase the bonding strength, regulate the drying speed, and extend the usable time.

[0013] Furthermore, the aforementioned silane coupling agent is bis-[3-(triethoxysilane)propyl]tetrasulfide.

[0014] The further beneficial effect of the above-mentioned method is that the silane coupling agent selected in this invention can increase the interaction between solvent 1 and solvents 2 and 3, forming stronger chemical bonds at the bonding interface, ensuring that the final bonding strength is superimposed and not weakened.

[0015] A method for preparing a binder for molding BJ silicon carbide ceramics specifically includes the following steps:

[0016] (1) Weigh each raw material according to the above-mentioned BJ silicon carbide ceramic molding binder parts by weight;

[0017] (2) Mix ethanol and phenolic resin, stir, add ethylene glycol or propanol, and cool to room temperature to obtain solvent 1;

[0018] (3) Stir and heat furfuryl alcohol, add formic acid or propionic acid, urea and the first part of paraformaldehyde, keep warm and stir, heat up, add hydrochloric acid and the second part of paraformaldehyde, keep warm and stir again, cool down to obtain solvent 2.

[0019] (4) Stir and heat furfuryl alcohol, add butyl acetate, stir and heat again to obtain solvent 3;

[0020] (5) Add solvent 3 to solvent 2, stir and cool, add solvent 1, heat up, keep warm and stir for the first time, add ethylenediamine, keep warm and stir for the second time, add silane coupling agent, keep warm and stir for the third time, add glycerol, keep warm and stir for the fourth time, cool to room temperature, and you will get BJ silicon carbide ceramic molding binder.

[0021] Furthermore, in step (2) above, the stirring temperature is room temperature or 40°C, and the stirring speed is 230 r / min until the phenolic resin is completely dissolved.

[0022] The further beneficial effect of the above-mentioned method is that the present invention uses ethanol to dilute the phenolic resin obtained by resin transfer molding (RTM) process, which can accelerate the dilution at low temperature, and then adds ethylene glycol or propanol as solvent 1.

[0023] Furthermore, in step (3) above, the stirring speed is 200 r / min, and the temperature is raised to 90°C; the stirring speed for heat preservation is 260 r / min, and the time is 30 min; the temperature is raised to 140°C; the stirring speed for heat preservation again is 300 r / min, and the time is 10 min; and the temperature is lowered to 90°C.

[0024] The further beneficial effect of the above-mentioned method lies in the fact that, in this invention, furfuryl alcohol, urea, and paraformaldehyde are added sequentially, and the reaction is carried out under acidic conditions at 90°C. The reaction utilizes the co-condensation of furfuryl alcohol and hydroxymethylurea, which are linked by ether bonds (-CH2OCH2-), as shown in the following formula:

[0025] ;

[0026] Then add hydrochloric acid and paraformaldehyde, and heat to 140℃, so that the excess furfuryl alcohol and the decomposed formaldehyde form a hemiacetal structure under acidic conditions, as shown in the following formula:

[0027] ;

[0028] Finally, the temperature was lowered to 90°C and used as solvent 2.

[0029] Furthermore, in step (4) above, the stirring speed is 200 r / min, and the temperature is raised to 70°C; the stirring speed is 200 r / min again, and the temperature is raised to 70°C.

[0030] The further beneficial effect of the above-mentioned method is that the present invention treats furfuryl alcohol with butyl acetate as solvent 3.

[0031] Furthermore, in step (5) above, the stirring speed for cooling is 260 r / min, cooling down to 70℃; heating up to 70℃; the first holding stirring speed is 260 r / min, time is 1 h; the second holding stirring temperature is 70℃, stirring speed is 260 r / min, time is 10 min; the third holding stirring temperature is 70℃, stirring speed is 260 r / min, time is 10 min; the fourth holding stirring temperature is 70℃, stirring speed is 260 r / min, time is 30 min.

[0032] The present invention also claims protection for the use of the above-described binder or the binder prepared by the above-described method in the molding of BJ silicon carbide ceramics.

[0033] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. This invention utilizes furfuryl alcohol and hydroxymethylurea to form a co-condensation structure through ether bonds, and furfuryl alcohol and formaldehyde to form a hemiacetal structure. The coexistence of these two structures can serve as a preform. The preform is blended with phenolic resin and furfuryl alcohol to form a highly stable binder. This binder has excellent bonding properties to silicon carbide powder, enabling BJ molding of silicon carbide powder, facilitating debinding and sintering, and facilitating reaction with silicon to generate β-phase silicon carbide during sintering.

[0035] 2. This invention modifies urea-formaldehyde resin obtained by stepwise polymerization, phenolic resin formed by RTM process, and furfural resin obtained by chain polymerization reaction by blending and modifying them, and then performs multi-stage filtration treatment to make it a special binder that can be used for BJ molding of silicon carbide ceramic powder. It has the advantages of high purity, high carbon content and high bonding strength, and simplifies the process steps, reduces production costs, and provides high-quality and high-efficiency silicon carbide ceramic parts for industrial applications.

[0036] 3. The viscosity and surface tension of the binder of this invention meet the corresponding requirements. The solid content of the molded silicon carbide parts is <2%, the tensile strength of the blank is >1MPa, the minimum wall thickness can reach 1mm, the carbon content is increased by more than 45%, and the structural limitations can be ignored. It can form hollow, complex, lattice structures that cannot be achieved by traditional technology, and can process various precision workpieces. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] BJ silicon carbide ceramic molding binder comprises the following raw materials by weight: 70g triglyceride, 30g bis-[3-(triethoxysilane)propyl]tetrasulfide and 2g ethylenediamine, as well as solvent 1, solvent 2 and solvent 3;

[0040] Solvent 1 includes the following raw materials by weight: 80g ethanol, 50g phenolic resin and 30g ethylene glycol;

[0041] Solvent 2 comprises the following raw materials by weight: 100g furfuryl alcohol, 10g formic acid, 6g urea, 2g paraformaldehyde (first part), 1g hydrochloric acid, and 1g paraformaldehyde (second part).

[0042] Solvent 3 comprises the following raw materials by weight: 70g furfuryl alcohol and 40g butyl acetate;

[0043] The preparation method of the above-mentioned binder for molding BJ silicon carbide ceramics specifically includes the following steps:

[0044] (1) Weigh each raw material according to the weight of the binder for BJ silicon carbide ceramic molding mentioned above;

[0045] (2) Mix ethanol and phenolic resin, stir at 230 r / min at 40°C until the phenolic resin is completely dissolved, add ethylene glycol, cool to room temperature, and obtain solvent 1;

[0046] (3) Stir furfuryl alcohol at 200 r / min and heat it to 90°C. Add formic acid, urea and the first part of paraformaldehyde. Stir at 260 r / min for 30 min. Heat it to 140°C. Add hydrochloric acid and the second part of paraformaldehyde. Stir at 300 r / min for 10 min. Cool it to 90°C to obtain solvent 2.

[0047] (4) Stir the furfuryl alcohol at 200 r / min and heat it to 70°C. Add butyl acetate and stir at 200 r / min to heat it to 70°C to obtain solvent 3.

[0048] (5) Add solvent 3 to solvent 2, stir at 260 r / min and cool to 70°C, add solvent 1, heat to 70°C, stir at 260 r / min for 1 h, add ethylenediamine, stir at 260 r / min for 10 min at 70°C, add bis-[3-(triethoxysilane)propyl]tetrasulfide, stir at 260 r / min for 10 min at 70°C, add triglycerides, stir at 260 r / min for 30 min at 70°C, and cool to room temperature to obtain the binder for BJ silicon carbide ceramic molding.

[0049] Example 2

[0050] BJ silicon carbide ceramic molding binder comprises the following raw materials by weight: 90g pentaglycerol, 40g bis-[3-(triethoxysilyl)propyl]tetrasulfide and 4g ethylenediamine, as well as solvent 1, solvent 2 and solvent 3;

[0051] Solvent 1 includes the following raw materials by weight: 100g ethanol, 80g phenolic resin and 40g propanol;

[0052] Solvent 2 comprises the following raw materials by weight: furfuryl alcohol 130g, formic acid 15g, urea 7g, first part paraformaldehyde 5g, hydrochloric acid 2g, and second part paraformaldehyde 2g.

[0053] Solvent 3 comprises the following raw materials by weight: 70g furfuryl alcohol and 40g butyl acetate;

[0054] The preparation method of the above-mentioned binder for molding BJ silicon carbide ceramics specifically includes the following steps:

[0055] (1) Weigh each raw material according to the weight of the binder for BJ silicon carbide ceramic molding mentioned above;

[0056] (2) Mix ethanol and phenolic resin, stir at 230 r / min at 40°C until the phenolic resin is completely dissolved, add propanol, and cool to room temperature to obtain solvent 1;

[0057] (3) Stir furfuryl alcohol at 200 r / min and heat it to 90°C. Add formic acid, urea and the first part of paraformaldehyde. Stir at 260 r / min for 30 min. Heat it to 140°C. Add hydrochloric acid and the second part of paraformaldehyde. Stir at 300 r / min for 10 min. Cool it to 90°C to obtain solvent 2.

[0058] (4) Stir the furfuryl alcohol at 200 r / min and heat it to 70°C. Add butyl acetate and stir at 200 r / min to heat it to 70°C to obtain solvent 3.

[0059] (5) Add solvent 3 to solvent 2, stir at 260 r / min and cool to 70°C, add solvent 1, heat to 70°C, stir at 260 r / min for 1 h, add ethylenediamine, stir at 260 r / min for 10 min at 70°C, add bis-[3-(triethoxysilane)propyl]tetrasulfide, stir at 260 r / min for 10 min at 70°C, add pentaglycerol, stir at 260 r / min for 30 min at 70°C, and cool to room temperature to obtain the binder for BJ silicon carbide ceramic molding.

[0060] Example 3

[0061] BJ silicon carbide ceramic molding binder comprises the following raw materials by weight: 90g diglycerol, 50g bis-[3-(triethoxysilane)propyl]tetrasulfide and 5g ethylenediamine, as well as solvent 1, solvent 2 and solvent 3;

[0062] Solvent 1 includes the following raw materials by weight: 100g ethanol, 100g phenolic resin and 60g ethylene glycol;

[0063] Solvent 2 comprises the following raw materials by weight: 150g furfuryl alcohol, 20g propionic acid, 10g urea, 5g paraformaldehyde (first part), 3g hydrochloric acid, and 2g paraformaldehyde (second part).

[0064] Solvent 3 comprises the following raw materials by weight: 70g furfuryl alcohol and 50g butyl acetate;

[0065] The preparation method of the above-mentioned binder for molding BJ silicon carbide ceramics specifically includes the following steps:

[0066] (1) Weigh each raw material according to the weight of the binder for BJ silicon carbide ceramic molding mentioned above;

[0067] (2) Mix ethanol and phenolic resin, stir at 230 r / min at 40°C until the phenolic resin is completely dissolved, add ethylene glycol, cool to room temperature, and obtain solvent 1;

[0068] (3) Stir furfuryl alcohol at 200 r / min and heat to 90°C, add propionic acid, urea and the first part of paraformaldehyde, keep warm and stir at 260 r / min for 30 min, heat to 140°C, add hydrochloric acid and the second part of paraformaldehyde, keep warm and stir at 300 r / min for 10 min, cool to 90°C to obtain solvent 2;

[0069] (4) Stir the furfuryl alcohol at 200 r / min and heat it to 70°C. Add butyl acetate and stir at 200 r / min to heat it to 70°C to obtain solvent 3.

[0070] (5) Add solvent 3 to solvent 2, stir at 260 r / min and cool to 70°C, add solvent 1, heat to 70°C, stir at 260 r / min for 1 h, add ethylenediamine, stir at 260 r / min for 10 min at 70°C, add bis-[3-(triethoxysilane)propyl]tetrasulfide, stir at 260 r / min for 10 min at 70°C, add diglycerol, stir at 260 r / min for 30 min at 70°C, and cool to room temperature to obtain the binder for BJ silicon carbide ceramic molding.

[0071] Example 4

[0072] BJ silicon carbide ceramic molding binder comprises the following raw materials by weight: 80g of triglycerides, 35g of bis-[3-(triethoxysilane)propyl]tetrasulfide and 4g of ethylenediamine, as well as solvent 1, solvent 2 and solvent 3;

[0073] Solvent 1 includes the following raw materials by weight: 75g ethanol, 50g phenolic resin and 35g propanol;

[0074] Solvent 2 comprises the following raw materials by weight: furfuryl alcohol 130g, propionic acid 15g, urea 8g, first part paraformaldehyde 4g, hydrochloric acid 3g, and second part paraformaldehyde 2g.

[0075] Solvent 3 comprises the following raw materials by weight: 60g furfuryl alcohol and 40g butyl acetate;

[0076] The preparation method of the above-mentioned binder for molding BJ silicon carbide ceramics specifically includes the following steps:

[0077] (1) Weigh each raw material according to the weight of the binder for BJ silicon carbide ceramic molding mentioned above;

[0078] (2) Mix ethanol and phenolic resin, stir at 230 r / min at 40°C until the phenolic resin is completely dissolved, add propanol, and cool to room temperature to obtain solvent 1;

[0079] (3) Stir furfuryl alcohol at 200 r / min and heat to 90°C, add propionic acid, urea and the first part of paraformaldehyde, keep warm and stir at 260 r / min for 30 min, heat to 140°C, add hydrochloric acid and the second part of paraformaldehyde, keep warm and stir at 300 r / min for 10 min, cool to 90°C to obtain solvent 2;

[0080] (4) Stir the furfuryl alcohol at 200 r / min and heat it to 70°C. Add butyl acetate and stir at 200 r / min to heat it to 70°C to obtain solvent 3.

[0081] (5) Add solvent 3 to solvent 2, stir at 260 r / min and cool to 70°C, add solvent 1, heat to 70°C, stir at 260 r / min for 1 h, add ethylenediamine, stir at 260 r / min for 10 min at 70°C, add bis-[3-(triethoxysilane)propyl]tetrasulfide, stir at 260 r / min for 10 min at 70°C, add triglycerides, stir at 260 r / min for 30 min at 70°C, and cool to room temperature to obtain the binder for BJ silicon carbide ceramic molding.

[0082] Example 5

[0083] BJ silicon carbide ceramic molding binder comprises the following raw materials by weight: 75g triglyceride, 35g bis-[3-(triethoxysilane)propyl]tetrasulfide and 2g ethylenediamine, as well as solvent 1, solvent 2 and solvent 3;

[0084] Solvent 1 includes the following raw materials by weight: 80g ethanol, 65g phenolic resin and 60g ethylene glycol;

[0085] Solvent 2 comprises the following raw materials by weight: furfuryl alcohol 100g, formic acid 13g, urea 6g, first part paraformaldehyde 3g, hydrochloric acid 1g, and second part paraformaldehyde 1g;

[0086] Solvent 3 comprises the following raw materials by weight: 60g furfuryl alcohol and 25g butyl acetate;

[0087] The preparation method of the above-mentioned binder for molding BJ silicon carbide ceramics specifically includes the following steps:

[0088] (1) Weigh each raw material according to the weight of the binder for BJ silicon carbide ceramic molding mentioned above;

[0089] (2) Mix ethanol and phenolic resin, stir at 230 r / min at 40°C until the phenolic resin is completely dissolved, add ethylene glycol, cool to room temperature, and obtain solvent 1;

[0090] (3) Stir furfuryl alcohol at 200 r / min and heat it to 90°C. Add formic acid, urea and the first part of paraformaldehyde. Stir at 260 r / min for 30 min. Heat it to 140°C. Add hydrochloric acid and the second part of paraformaldehyde. Stir at 300 r / min for 10 min. Cool it to 90°C to obtain solvent 2.

[0091] (4) Stir the furfuryl alcohol at 200 r / min and heat it to 70°C. Add butyl acetate and stir at 200 r / min to heat it to 70°C to obtain solvent 3.

[0092] (5) Add solvent 3 to solvent 2, stir at 260 r / min and cool to 70°C, add solvent 1, heat to 70°C, stir at 260 r / min for 1 h, add ethylenediamine, stir at 260 r / min for 10 min at 70°C, add bis-[3-(triethoxysilane)propyl]tetrasulfide, stir at 260 r / min for 10 min at 70°C, add triglycerides, stir at 260 r / min for 30 min at 70°C, and cool to room temperature to obtain the binder for BJ silicon carbide ceramic molding.

[0093] Performance testing

[0094] The adhesives prepared in Examples 1-5 were used to test their viscosity and surface tension, as well as the solid content, tensile strength, wall thickness, and carbon content of the silicon carbide parts molded with the adhesives.

[0095] The testing method is as follows:

[0096] 1. Viscosity

[0097] After the adhesive has cooled to room temperature, use a viscometer and a No. 0 rotor to test the viscosity of the adhesive. The viscosity range should be 7-9 cps.

[0098] 2. Surface tension

[0099] Use a surface tension meter to test the surface tension of the adhesive; the surface tension should be between 15-30 mN / m.

[0100] 3. Solid content

[0101] The binder is fed into a BJ molding machine for silicon carbide powder molding, using powder particles <50μm and a molding layer thickness of 0.1mm. After molding, it is placed in an oven at 200℃ for 4 hours for enhanced curing. During the molding process, the binder consumption for different structures is monitored using a flow meter, which indicates the solid content in the molded silicon carbide parts.

[0102] 4. Tensile strength

[0103] After curing, the tensile strength of the green blank was tested using an intelligent strength tester.

[0104] 5. Wall thickness

[0105] Use vernier calipers to measure the wall thickness of the green blank.

[0106] 6. Increase carbon content

[0107] The carbon content in the molded silicon carbide parts was detected by infrared spectroscopy. By calculating and removing the carbon content from the silicon carbide powder, the increased carbon content of the binder was obtained.

[0108] The results are shown in Table 1.

[0109] Table 1 Performance test results of adhesives in Examples 1-5

[0110]

[0111] As shown in Table 1, the viscosity and surface tension of the binders in Examples 1-5 all meet the corresponding requirements, the solid content of the molded silicon carbide parts is <2%, the tensile strength of the blank is >1MPa, the minimum wall thickness can reach 1mm, and the carbon content is increased by more than 45%.

[0112] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for producing a binder for BJ silicon carbide ceramics molding, characterized by, Specifically comprising the following steps: (1) the following raw materials are weighed by weight fraction: glycerol 70-90 parts, silane coupling agent 30-50 parts and ethylenediamine 2-5 parts, and solvent 1, solvent 2 and solvent 3; The glycerol is at least one of dipolyglycerol, tri-polyglycerol and penta-polyglycerol; The silane coupling agent is bis-[3-(triethoxysil) propyl] tetrasulfide; The solvent 1 includes the following raw materials by weight fraction: ethanol 75-100 parts, phenolic resin 50-100 parts and ethylene glycol or propyl alcohol 30-60 parts; The solvent 2 includes the following raw materials by weight fraction: furfuryl alcohol 100-150 parts, formic acid or propionic acid 10-20 parts, urea 5-10 parts, first part of paraformaldehyde 2-5 parts, hydrochloric acid 1-3 parts and second part of paraformaldehyde 1-2 parts; The solvent 3 includes the following raw materials by weight fraction: furfuryl alcohol 50-70 parts and butyl acetate 20-50 parts; (2) ethanol and phenolic resin are mixed, stirred, ethylene glycol or propyl alcohol is added, and cooled to room temperature to obtain solvent 1; (3) furfuryl alcohol is stirred and heated to 90℃, formic acid or propionic acid, urea and first part of paraformaldehyde are added, and heated and stirred, heated to 140℃, hydrochloric acid and second part of paraformaldehyde are added, and heated and stirred again, and cooled to obtain solvent 2; (4) furfuryl alcohol is stirred and heated, butyl acetate is added, and heated and stirred again to obtain solvent 3; (5) solvent 3 is added to solvent 2, stirred and cooled, solvent 1 is added, heated, first heated and stirred, ethylenediamine is added, second heated and stirred, silane coupling agent is added, third heated and stirred, glycerol is added, fourth heated and stirred, and cooled to room temperature to obtain the BJ silicon carbide ceramic forming binder.

2. The method for preparing a binder for molding BJ silicon carbide ceramics according to claim 1, characterized in that, In step (2), the stirring temperature is room temperature or 40℃, and the rotating speed is 230r / min until the phenolic resin is completely dissolved.

3. The method for preparing a binder for molding BJ silicon carbide ceramics according to claim 1, characterized in that, In step (3), the rotating speed of the stirring and heating is 200r / min; the rotating speed of the heated and stirred is 260r / min, and the time is 30min; the rotating speed of the again heated and stirred is 300r / min, and the time is 10min; and the temperature is cooled to 90℃.

4. The method of claim 1, wherein the binder for forming a BJ silicon carbide ceramic is prepared by adding 0.5 to 5 parts by weight of the dispersant to 100 parts by weight of the binder. In step (4), the rotating speed of the stirring and heating is 200r / min, and the temperature is heated to 70℃; the rotating speed of the again stirring and heating is 200r / min, and the temperature is heated to 70℃.

5. The method for preparing a binder for molding BJ silicon carbide ceramics according to claim 1, characterized in that, In step (5), the rotating speed of the stirring and cooling is 260r / min, and the temperature is cooled to 70℃; and the temperature is heated to 70℃.

6. The method for preparing a binder for molding BJ silicon carbide ceramics according to claim 1, characterized in that, In step (5), the rotating speed of the first heated and stirred is 260r / min, and the time is 1h; the temperature of the second heated and stirred is 70℃, the rotating speed is 260r / min, and the time is 10min; the temperature of the third heated and stirred is 70℃, the rotating speed is 260r / min, and the time is 10min; the temperature of the fourth heated and stirred is 70℃, the rotating speed is 260r / min, and the time is 30min.

7. The application of the binder prepared by the preparation method of claim 1 in BJ silicon carbide ceramic forming.

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