A method for preparing a high-precision gel-injection pressureless sintered silicon carbide ceramic water jet sand pipe

Abstract

The application relates to a preparation method of a high-precision gel injection pressureless sintering silicon carbide ceramic water jet sand pipe, which comprises the following steps: pouring a premixed solution into a mold to obtain a blank body through solidification; taking out the solidified blank body from the inner mold, then placing the outer mold and the blank body into a polyethylene glycol solution for drying, the blank body shrinks during drying in the polyethylene glycol solution, and demolding is completed; drying the demolded blank body on a drying device, vacuum heating, and obtaining a dried blank body; pressureless sintering the dried blank body, and obtaining a product silicon carbide ceramic water jet sand pipe after sintering; the premixed solution comprises monomers, a crosslinking agent, a dispersing agent, a defoaming agent, modified silicon carbide powder, a sintering aid and tetramethylammonium hydroxide; the modified silicon carbide powder comprises graphene composite silicon carbide and modified carbon nanotubes. The application has the effect of improving the product quality of the prepared water jet sand pipe.

Description

TECHNICAL FIELD

[0001] The application relates to the field of ceramic materials, in particular to a preparation method of a high-precision gel-injection pressureless-sintering silicon carbide ceramic water jet abrasive tube. BACKGROUND

[0002] The abrasive tube is the key to form the abrasive jet. For a long time, the high-pressure abrasive jet abrasive tube has been a problem in the water jet field in China. So far, the service life of the abrasive tube for cutting and the front mixed abrasive jet nozzle has not reached a satisfactory level.

[0003] The abrasive tube on the market is generally made of composite tungsten carbide material. However, compared with tungsten carbide material, silicon carbide ceramic material not only has excellent corrosion resistance, high wear resistance and low friction coefficient, but also has the best high-temperature mechanical properties (strength, creep resistance, etc.) among known ceramic materials, and has a lower price, so it is more suitable for preparing the abrasive tube.

[0004] However, there is almost no silicon carbide ceramic water jet abrasive tube on the market, and the few existing ones are basically first prepared into the external shape of the water jet abrasive tube by a pressing forming method, and then further processed by a mechanical processing method. However, this method has many defects such as low yield, subsequent mechanical processing difficulty, low economic benefit, energy waste and the like. How to use a suitable forming method to prepare a high-performance silicon carbide ceramic water jet abrasive tube, improve its yield, ensure its precision and help its batch production is a problem to be solved in the market. SUMMARY

[0005] In order to improve the product quality of the prepared silicon carbide ceramic water jet abrasive tube, the application provides a preparation method of a high-precision gel-injection pressureless-sintering silicon carbide ceramic water jet abrasive tube.

[0006] The preparation method of the high-precision gel-injection pressureless-sintering silicon carbide ceramic water jet abrasive tube provided by the application adopts the following technical scheme:

[0007] A preparation method of a high-precision gel-injection pressureless-sintering silicon carbide ceramic water jet abrasive tube, comprising the following steps:

[0008] S1, pouring the premixed liquid into the mold to obtain a green body by solidification;

[0009] S2, taking out the solidified green body from the inner mold, and then placing the outer mold and the green body into a polyethylene glycol solution for drying. The green body shrinks when dried in the polyethylene glycol liquid, and the demolding is completed;

[0010] S3, drying the demolded green body on a drying device, vacuum heating, to obtain a dried green body;

[0011] S4, the dried embryo body is subjected to pressureless sintering, and after sintering, a product, a silicon carbide ceramic water jet sand pipe, is obtained;

[0012] The premix liquid comprises monomers, cross-linking agents, dispersants, defoaming agents, modified silicon carbide powder, sintering aids, and tetramethylammonium hydroxide.

[0013] By adopting the above technical solution, the silicon carbide ceramic water jet sand pipe is prepared by adopting the gel injection molding process, the modified silicon carbide powder in the premix liquid is prepared by graphene composite silicon carbide, modified carbon nanotubes, and a binder, silicon carbide is a strong covalent compound, and the crystal boundary can be strengthened after sintering, and the grain is refined, thereby improving the toughness of the prepared silicon carbide ceramic, so that the mechanical strength of the material is improved, and the toughness of the silicon carbide ceramic water jet sand pipe can be further improved after the silicon carbide is improved by graphene, thereby improving the bonding capacity, further improving the quality of the prepared product, and at the same time, the modified carbon nanotubes are added, the carbon nanotubes have good mechanical properties and a very high aspect ratio, which can significantly improve the strength and toughness of the product, also improve the bonding performance of each component, and improve the deformation phenomenon caused by shrinkage, thereby further improving the stability of the prepared product.

[0014] Preferably, the modified carbon nanotubes comprise carbon nanotubes, white carbon black, methacrylic acid, and zinc oxide.

[0015] By adopting the above technical solution, the carbon nanotubes have a high aspect ratio and strength, and have good mechanical strength, however, because the aspect ratio is too large, there is a nanometer size effect, and the surface active groups of the carbon nanotubes are less, and the compatibility in the system is poor, ordinary carbon nanotubes may agglomerate, after the carbon nanotubes are modified by acrylic acid, the number of surface groups of the carbon nanotubes is increased, the compatibility of the carbon nanotubes in the system is improved, and at the same time, the dispersibility of the carbon nanotubes in the system is improved, thereby further improving the stability of the prepared product.

[0016] Preferably, the modified carbon nanotubes are prepared by the following method:

[0017] The carbon nanotubes and the methacrylic acid are mixed, heated and stirred, then the zinc oxide and the white carbon black are added and continue to be stirred, the methacrylic acid is added during the stirring process, and after the stirring, the modified carbon nanotubes are obtained after washing and drying.

[0018] By adopting the above technical solution, the methacrylic acid and the zinc oxide react in situ to generate zinc methacrylate, and at the same time, the carbon nanotubes are coated, and finally the modified carbon nanotubes are obtained, the dispersibility of the modified carbon nanotubes is improved, thereby further improving the stability of the product.

[0019] As preferred, the mass ratio between the carbon nanotube, white carbon black, methacrylic acid and zinc oxide is 1:0.5:(1.4-1.6):0.5.

[0020] By adopting the above technical solution, the mass ratio between the carbon nanotube, white carbon black, methacrylic acid and zinc oxide is within the above range, which can further improve the stability of the modified carbon nanotube prepared.

[0021] As preferred, the graphene composite silicon carbide is prepared by the following method:

[0022] The silicon carbide nano is mixed with anhydrous ethanol to obtain a silicon carbide dispersion liquid, the silicon carbide dispersion liquid is radiated by a laser, then the silicon carbide dispersion liquid after laser radiation is centrifuged and washed, the washed powder is mixed with hydrofluoric acid and hydrochloric acid, stirred until acidic, centrifuged and washed again, and dried to obtain graphene composite silicon carbide.

[0023] By adopting the above technical solution, after the laser bombardment on the surface of the silicon carbide nano particles, the chemical bonds in the silicon carbide can be broken, the Si atoms can be sublimated, the C atoms can be combined with each other to form graphene, and the graphene can continuously form a coating structure, the generated graphene closely adheres to the surface of the silicon carbide nano particles and continuously extends to form a graphene floating belt, so as to promote the close combination between the graphene composite silicon carbide, and thus the quality of the product is improved.

[0024] As preferred, the mass ratio between the modified carbon nanotube and the graphene composite silicon carbide is (0.085-0.095):1.

[0025] By adopting the above technical solution, the mass ratio between the modified carbon nanotube and the graphene composite silicon carbide is within the above range, which can further improve the stability of the modified silicon carbide powder prepared.

[0026] As preferred, the mass ratio between the monomer and the crosslinking agent is (10-15):1, the defoaming agent accounts for 0.1-0.2% of the ceramic powder, and the sintering aid accounts for 1-2.5% of the ceramic powder.

[0027] As preferred, the mass ratio between the monomer and the crosslinking agent is (10-15):1, the defoaming agent accounts for 0.1-0.2% of the ceramic powder, and the sintering aid accounts for 1-2.5% of the ceramic powder.

[0028] As preferred, the defoaming agent includes n-octanol, the sintering aid includes carbon and silicon carbide, the catalyst includes tetramethyl ethylenediamine, and the initiator includes ammonium persulfate.

[0029] As preferred, the premixed slurry is prepared by the following method:

[0030] The monomer and crosslinking agent are added to water, after stirring and mixing, the dispersant, defoaming agent, silicon carbide powder and sintering aid are added, then the tetramethylammonium hydroxide is added, the ball is mixed for 2h, then vacuum degassing is carried out, to obtain a premix liquid, the catalyst and initiator are added to the premix liquid to obtain a premix slurry.

[0031] In summary, the present application includes at least one of the following beneficial technical effects:

[0032] 1. In the present application, the modified silicon carbide powder prepared by graphene composite silicon carbide and modified carbon nanotubes has good toughness, and the bonding ability between each component in the system is improved, thereby improving the solid content of the prepared green body. The modified carbon nanotube has a high aspect ratio, which improves the strength and toughness of the product, further improves the bonding performance between each component, and improves the shrinkage deformation phenomenon of the product, thereby improving the stability of the prepared product;

[0033] 2. The surface of the carbon nanotube is modified by acrylic acid, which improves the number of groups on the surface of the carbon nanotube, thereby improving the compatibility of the carbon nanotube in the system. The modified carbon nanotube can be uniformly dispersed in the system, thereby improving the stability of the prepared modified silicon carbide powder to improve the product quality;

[0034] 3. After laser bombardment on the surface of the silicon carbide nanoparticles, the chemical bonds in the silicon carbide are broken, the Si atoms are sublimated, the C atoms are combined with each other to form graphene, and the coating structure is continuously formed. The generated graphene closely adheres to the surface of the silicon carbide particles and continuously extends to form a graphene floating belt, which promotes the close combination between graphene and silicon carbide, and further improves the product quality. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is an exploded structure schematic diagram of the mold in the embodiment of the present application.

[0036] Figure 2 is a partial cross-sectional schematic diagram for showing the structure of the drying device in the embodiment of the present application.

[0037] Figure 3 is a sintering tool drawing in the embodiment of the present application.

[0038] BRIEF DESCRIPTION OF DRAWINGS

[0039] 1, sand pipe cover; 11, feed inlet; 2, sand pipe outer mold; 21, first outer mold; 22, second outer mold; 23, pouring groove; 3, sand pipe base; 4, drying equipment; 41, machine body; 42, first rolling shaft; 43, second rolling shaft; 44, protective shell. DETAILED DESCRIPTION

[0040] The following description is made in connection with Figures 1 to 2 The application is further described in detail.

[0041] The application discloses a preparation method of a high-precision gel pressureless sintering silicon carbide ceramic water jet sand pipe.

[0042] Referring to Figure 1 The mold comprises a sand pipe cover 1, a sand pipe outer mold 2 and a sand pipe base 3. The sand pipe outer mold 2 comprises a sand pipe first outer mold 21 and a sand pipe second outer mold 22. The sand pipe first outer mold 21 and the sand pipe second outer mold 22 are fixed by cooperation of positioning pins. The sand pipe outer mold 2 and the sand pipe cover 1 are fixed by cooperation of positioning pins. The sand pipe cover 1 is provided with a feeding port 11. Five pouring grooves 23 are formed in the sand pipe outer mold 2. The slurry is poured into the middlemost pouring groove 23 in the sand pipe outer mold 2 through the feeding port 11. By using the U-shaped pipe principle, all the pouring grooves 23 except the middlemost one are poured from the bottom to the top through the flow-through grooves of the sand pipe base 3. Finally, the pouring is completed.

[0043] Referring to Figure 2 The drying device 4 comprises a machine body 41, a first rolling shaft 42 and a second rolling shaft 43. The two ends of the first rolling shaft 42 are connected with the inner wall bearings of the machine body 41. The first rolling shaft 42 and the second rolling shaft 43 are parallel to each other and located at the same height position. The first rolling shaft 42 and the second rolling shaft 43 rotate in the same direction. The first rolling shaft 42 and the second rolling shaft 43 are connected by belt pulleys outside. One end of the first rolling shaft 42 penetrates the machine body 41 and is connected with a rotating motor, so as to drive the first rolling shaft 42 to rotate. The green body after demolding is placed on the rolling shaft to rotate, so as to reduce the deformation of the green body during drying. The drying device 4 is further provided with a protective shell 44. In the embodiment, the protective shell 44 is a transparent glass cover. The protective shell 44 is fixedly connected with the machine body 41, so as to close the whole drying device 4. In other embodiments, the protective shell 44 can be detachably connected with the machine body 41, so that the protective shell 44 can be opened by the staff. The machine body 41 is further provided with a temperature controller capable of adjusting the heating rate, so as to dry the green body.

[0044] The application is further described in detail in connection with the following embodiments:

[0045] Raw material description: all raw materials in the examples can be obtained by market purchase; among them, the crosslinking agent is N,N'-methylene bisacrylamide (CAS number: 110-26-9), the monomer is acrylamide (CAS number: 79-06-1), the dispersing agent is a mixture of dispersing agent CE64 and dispersing agent SOPA (model number: DYSP-270) with a mass ratio of 1:1; the defoaming agent is n-octanol (CAS number: 111-87-5); the sintering aid is a mixture of carbon and boron carbide with a mass ratio of 1:1; the catalyst is tetramethylethylenediamine (CAS number: 110-18-9), and the initiator is ammonium persulfate with a mass fraction of 5%.

[0046] Example 1

[0047] Preparation of graphene composite silicon carbide:

[0048] Silicon carbide nanoparticles and anhydrous ethanol were mixed with a mass ratio of 1:50, ultrasonic dispersion for 0.5h until the bottom of the sediment, to obtain a silicon carbide dispersion, the silicon carbide dispersion was irradiated by a laser for 20min, stirring during the irradiation to prevent the particles from sinking to the bottom, then, the laser-irradiated silicon carbide dispersion was centrifuged and washed with deionized water, the centrifuged powder was mixed with hydrofluoric acid and hydrochloric acid, stirred until acidic, repeated acid washing three times, finally washed with anhydrous ethanol, centrifuged and dried at 60℃ for 12h to obtain graphene composite silicon carbide.

[0049] Preparation of modified carbon nanotubes

[0050] 147.06g of carbon nanotubes were mixed with 154.41g of methacrylic acid (CAS number: 79-41-4), heated to 60℃, stirred at 1500r / min for 5min, then 73.53g of zinc oxide and 73.53g of white carbon black were added, and the stirring was continued, 51.47g of methacrylic acid was added during stirring, and after stirring, ethanol was used for washing, and dried at 80℃ for 6h to obtain modified carbon nanotubes.

[0051] Preparation of modified silicon carbide powder:

[0052] 156.68g of modified carbon nanotubes, 1843.32g of graphene composite silicon carbide were added to 6000mL of N-methylpyrrolidone (CAS number: 872-50-4), then ultrasonic treatment for 10min to make the modified carbon nanotubes and graphene composite silicon carbide fully mixed, after ultrasonic treatment, ethanol was used for washing, and then dried at 70℃ to obtain modified silicon carbide powder.

[0053] Preparation of premix liquid:

[0054] 65g of monomer and 6.5g of crosslinking agent were added to 300g of deionized water, after stirring and mixing, 13g of dispersant, 1.3g of defoaming agent, 1300g of silicon carbide powder and 13g of sintering aid were added, then 0.085g of tetramethylammonium hydroxide was added, ball mixing for 2h, then vacuum degassing, adding 0.1g of catalyst and 0.1g of initiator to obtain a premix.

[0055] Preparation of high-precision pressureless sintering silicon carbide ceramic water jet sand pipe:

[0056] S1, pouring the premix into the mold, keeping 16℃ to solidify to obtain a blank;

[0057] S2, taking out the cured blank from the inner mold, then putting the outer mold and the blank into the polyethylene glycol solution for drying for 2h, the blank shrinks when drying in the polyethylene glycol liquid, and the demolding is completed;

[0058] S3, drying the demolded blank on the drying equipment, and heating to 100℃ under vacuum to obtain a dried blank; S4, placing the dried blank on the sintering tool for pressureless sintering, and after sintering, obtaining the product silicon carbide ceramic water jet sand pipe.

[0059] In step S4, the temperature rising curve is referred to Table 1.

[0060] Example 2

[0061] Preparation of graphene composite silicon carbide:

[0062] Mixing silicon carbide nanoparticles and anhydrous ethanol with a mass ratio of 1:50, ultrasonic dispersion for 0.5h until the bottom of the sediment, to obtain a silicon carbide dispersion, the silicon carbide dispersion is irradiated by a laser for 20min, stirring during the irradiation to prevent the particles from sinking to the bottom, then, the silicon carbide dispersion after laser irradiation is centrifuged and washed with deionized water, the centrifuged powder is mixed with hydrofluoric acid and hydrochloric acid, stirred until acidic, and the acid washing is repeated three times, finally washed with anhydrous ethanol, centrifuged and dried at 60℃ for 12h to obtain graphene composite silicon carbide.

[0063] Preparation of modified carbon nanotubes

[0064] Mixing 138.89g of carbon nanotubes with 166.68g of methacrylic acid, heating to 60℃, stirring at 1500r / min for 5min, then adding 69.44g of zinc oxide and 69.44g of white carbon black, continuing to stir, adding 55.56g of methacrylic acid during stirring, stirring and washing with ethanol, drying at 80℃ for 6h to obtain modified carbon nanotubes.

[0065] Preparation of modified silicon carbide powder:

[0066] Add 173.52 g of modified carbon nanotubes, 1826.48 g of graphene composite silicon carbide into 6000 mL of N-methyl pyrrolidone, then ultrasonic treatment for 10 min, so that the modified carbon nanotubes and graphene composite silicon carbide are fully mixed, after ultrasonic, washed with ethanol, then dried at a temperature of 70℃, to obtain modified silicon carbide powder.

[0067] Prepare a premix solution:

[0068] Add 75 g of monomer and 7.5 g of crosslinking agent to 350 g of deionized water, after stirring and mixing, add 30 g of dispersing agent, 3 g of defoaming agent, 1500 g of silicon carbide powder and 37.5 g of sintering aid, then add 0.2 g of tetramethylammonium hydroxide, ball mix for 2 h, then vacuum degassing, add 0.2 g of catalyst and 0.2 g of initiator, to obtain the premix solution.

[0069] Preparation of high-precision pressureless sintered silicon carbide ceramic water jet sand pipe:

[0070] S1, pour the premix solution into the mold, keep it at 16℃ to solidify to obtain a green body;

[0071] S2, take out the solidified green body from the inner mold, then put the outer mold and the green body into the polyethylene glycol solution for drying for 3 h, the green body shrinks when drying in the polyethylene glycol liquid, and the demolding is completed;

[0072] S3, dry the demolded green body on the drying equipment, and heat it to 100℃ under vacuum, to obtain the dried green body; S4, place the dried green body on the sintering tool for pressureless sintering, after sintering, obtain the product silicon carbide ceramic water jet sand pipe.

[0073] In step S3, the temperature rising curve is referred to Table 1.

[0074] Example 3

[0075] Preparation of graphene composite silicon carbide:

[0076] Mix the silicon carbide nanoparticles with anhydrous ethanol at a mass ratio of 1:50, ultrasonic dispersion for 0.5 h until the bottom of the sediment, to obtain a silicon carbide dispersion, irradiate the silicon carbide dispersion with a laser for 20 min, stir during the irradiation to prevent the particles from sinking to the bottom, then centrifuge the laser-irradiated silicon carbide dispersion and wash with deionized water, mix the centrifuged powder with hydrofluoric acid and hydrochloric acid, stir until acidic, repeat the acid washing three times, finally wash with anhydrous ethanol, centrifuge and dry at a temperature of 60℃ for 12 h, to obtain graphene composite silicon carbide.

[0077] Preparation of modified carbon nanotubes

[0078] Mix 142.86 g of carbon nanotubes with 214.28 g of methacrylic acid, heat to 60°C, stir at 1500 r / min for 5 min, then add 71.43 g of zinc oxide and 71.43 g of white carbon black, continue to stir, and add 53.57 g of methacrylic acid during stirring. After stirring, wash with ethanol, and dry at 80°C for 6 h to obtain modified carbon nanotubes.

[0079] Preparation of modified silicon carbide powder:

[0080] Add 148.15 g of modified carbon nanotubes, 1851.85 g of graphene composite silicon carbide to 6000 mL of N-methyl pyrrolidone, then ultrasonic treat for 10 min to fully mix the modified carbon nanotubes and graphene composite silicon carbide. After ultrasonic treatment, wash with ethanol, and then dry at 70°C to obtain modified silicon carbide powder.

[0081] Preparation of premix:

[0082] Add 70 g of monomer and 7 g of crosslinking agent to 320 g of deionized water, stir and mix, then add 21 g of dispersing agent, 2.1 g of defoaming agent, 1400 g of silicon carbide powder, and 25.3 g of sintering aid. Then add 0.143 g of tetramethylammonium hydroxide, ball mix for 2 h, then vacuum degassing. Add 0.15 g of catalyst and 0.15 g of initiator to obtain the premix.

[0083] Preparation of high-precision pressureless sintered silicon carbide ceramic water jet sand pipe:

[0084] S1, pour the premix into the mold, and keep at 16°C to obtain a green body;

[0085] S2, take out the inner mold of the cured green body, then place the outer mold and the green body in a polyethylene glycol solution for drying for 2.5 h. The green body shrinks during drying in the polyethylene glycol solution and is demolded;

[0086] S3, dry the demolded green body on a drying device, and vacuum heat to 100°C to obtain a dried green body; S4, place the dried green body on a sintering tool for pressureless sintering. After sintering, a product silicon carbide ceramic water jet sand pipe is obtained.

[0087] In step S3, the temperature rising curve is referred to Table 1.

[0088] Example 4

[0089] Example 4 is based on Example 3, and the difference between Example 4 and Example 3 is that in Example 4, when preparing the modified carbon nanotubes, the carbon nanotubes used are 156.25 g, the white carbon black is 78.125 g, the methacrylic acid is 187.5 g, and the zinc oxide is 78.125 g.

[0090] Example 5

[0091] Example 5 is based on Example 3, and the difference between Example 5 and Example 3 is that in Example 5, when preparing the modified carbon nanotubes, the carbon nanotubes used are 131.58 g, the white carbon black is 65.79 g, the methacrylic acid is 236.84 g, and the zinc oxide is 65.79 g.

[0092] Example 6

[0093] Example 6 is based on Example 3, and the difference between Example 6 and Example 3 is that in Example 6, when preparing the modified silicon carbide powder, the modified carbon nanotubes used are 113.21 g, and the graphene composite silicon carbide is 1886.79 g.

[0094] Example 7

[0095] Example 7 is based on Example 3, and the difference between Example 7 and Example 3 is that in Example 7, when preparing the modified silicon carbide powder, the modified carbon nanotubes used are 214.29 g, and the graphene composite silicon carbide is 1785.71 g.

[0096] Example 8

[0097] Example 8 is based on Example 3, and the difference between Example 8 and Example 3 is that in Example 8, when preparing the modified silicon carbide powder, only silicon carbide and graphene are mixed in a mass ratio of 1:0.1 to obtain.

[0098] Example 9

[0099] Example 9 is based on Example 3, and the difference between Example 9 and Example 3 is that in Example 9, when preparing the modified silicon carbide composite powder, the modified carbon nanotubes are replaced by ordinary carbon nanotubes.

[0100] Comparative Example 1

[0101] Comparative Example 1 is based on Example 3, and the difference between Comparative Example 1 and Example 3 is that in Comparative Example 1, the modified silicon carbide powder is replaced by ordinary silicon carbide powder.

[0102] Table 1 Vacuum drying temperature curve in step (3)

[0103]

[0104] Performance test

[0105] The samples of Examples 1-9 and Comparative Example 1 were sampled and subjected to the following performance tests:

[0106] (1) Surface condition after drying

[0107] The wet blanks were subjected to drying treatment, and the condition of the dry blanks after drying was observed and recorded, and the results are recorded in Table 2.

[0108] (2) Bending strength

[0109] The bending strength of the samples was tested according to the detection standard of GB / T 6569-2006 Fine Ceramic Bending Strength Test Method, and the test was performed three times at room temperature for each sample, and the average value was taken, and the test results were filled in Table 2.

[0110] (3) Hardness

[0111] The detection was performed using a Vickers hardness tester according to the standard of GB 16534-2009 Fine Ceramic Room Temperature Hardness Test Method, the Vickers hardness of the sample was calculated, each sample was tested three times, and the average value was taken after measurement, and the results are recorded in Table 2.

[0112] Table 2 Test results of samples of Examples 1-9 and Comparative Example 1

[0113]

[0114]

[0115] As can be seen from Table 1, the surfaces of the samples of Examples 1-3 are free of cracking, the bending strength is 360 MPa or more, and the hardness is 25 or more, indicating that the silicon carbide ceramic water jet sand pipe prepared by the application has good stability and strength.

[0116] In the preparation of modified carbon nanotubes of Example 4 and Example 5, the carbon nanotubes, white carbon black, methacrylic acid and zinc oxide are not within the scope defined by the application. When the content of methacrylic acid is too low, the content of active groups connected to the surface of the carbon nanotubes is low, making it difficult to further improve the dispersion performance of the carbon nanotubes. At the same time, the etching effect on the surface of the carbon nanotubes is difficult to further improve, making it difficult to further improve the roughness of the carbon nanotubes, and the combination ability in the system decreases, affecting the product quality; when the content of methacrylic acid is too high, the etching of the carbon nanotubes is too large, affecting the stability of the carbon nanotubes, so the overall stability of the system decreases, therefore, the performance of Example 4 and Example 5 decreases.

[0117] The mass ratio between the modified carbon nanotubes and the graphene composite silicon carbide in the preparation of the modified silicon carbide powder in Example 6 and Example 7 is not within the range defined in the present application. When the content of the modified carbon nanotubes is too high or too low, the stability of the prepared premix solution is affected, thereby causing the quality of the prepared product to decrease, and thus the performance of Example 6 and Example 7 is decreased.

[0118] The modified silicon carbide powder in Example 8 is obtained by mixing silicon carbide and graphene. The combination between the ordinary mixed silicon carbide and graphene is poor, and the graphene is aggregated in the system, thereby causing the stability to decrease. Therefore, the quality of the prepared water jet sand pipe product is also decreased, and thus the performance of Example 8 is decreased.

[0119] In Example 9, the modified carbon nanotubes are replaced by ordinary carbon nanotubes in the preparation of the modified silicon carbide composite powder. The surface of the unmodified carbon nanotubes has no more active groups, and the compatibility in the system is difficult to improve. At the same time, the surface is not etched, and the roughness is difficult to improve. The combination in the system is decreased, thereby affecting the quality of the product, and thus the performance of Example 9 is decreased.

[0120] In Comparative Example 1, the modified silicon carbide powder is replaced by ordinary silicon carbide powder. The compatibility and connection strength of the ordinary silicon carbide powder are difficult to improve, and thus the quality of the prepared product is difficult to improve. Therefore, the performance of Comparative Example 1 is decreased.

[0121] The specific embodiments are merely an explanation of the present application, and are not a limitation of the present application. Through the above description, relevant personnel can make various changes and modifications without deviating from the technical concept of the present application. The technical scope of the present application is not limited to the content in the specification, and must be determined according to the scope of the claims.

Claims

1. A method for preparing a high-precision gel-cast pressureless sintered silicon carbide ceramic waterjet abrasive tube, characterized in that: It comprises the following steps: S1, pouring the premixed liquid into the mold to obtain a blank after curing; S2, taking out the cured blank from the inner mold, then placing the outer mold and the blank into the polyethylene glycol solution for drying, the blank shrinks when drying in the polyethylene glycol liquid, and the demolding is completed; S3, drying the demolded blank in a drying device under vacuum heating to obtain a dried blank; S4, pressureless sintering the dried blank, and obtaining a product of silicon carbide ceramic water jet sand pipe after sintering; The premixed liquid comprises monomers, cross-linking agents, dispersants, defoaming agents, modified silicon carbide powder, sintering aids and tetramethylammonium hydroxide, and the modified silicon carbide powder comprises graphene composite silicon carbide and modified carbon nanotubes; The raw materials for preparing the modified carbon nanotubes comprise carbon nanotubes, white carbon black, methacrylic acid and zinc oxide; The modified carbon nanotubes are prepared by the following method: Mix the carbon nanotubes and methacrylic acid, stir after heating, then add zinc oxide and white carbon black, continue to stir, add methacrylic acid during stirring, wash and dry after stirring to obtain modified carbon nanotubes; The mass ratio between the carbon nanotubes, white carbon black, methacrylic acid and zinc oxide is 1:0.5:(1.4-1.6):0.5; The graphene composite silicon carbide is prepared by the following method: Mix nano silicon carbide and anhydrous ethanol to obtain a silicon carbide dispersion liquid, irradiate the silicon carbide dispersion liquid by a laser, then centrifuge and wash the silicon carbide dispersion liquid after laser irradiation, mix the washed powder with hydrofluoric acid and hydrochloric acid, stir until acidic, centrifuge and wash again, and dry to obtain graphene composite silicon carbide; The mass ratio between the modified carbon nanotubes and the graphene composite silicon carbide is (0.085-0.095):

1.

2. The method according to claim 1, wherein the method is characterized by: The mass ratio between the monomers and the cross-linking agent is (10-15):1, the defoaming agent accounts for 0.1-0.2wt% of the modified silicon carbide powder, and the sintering aid accounts for 1-2.5wt% of the modified silicon carbide powder.

3. The method according to claim 1, wherein the method is characterized by: The defoaming agent comprises n-octanol, and the sintering aid comprises carbon and silicon carbide.

4. The method according to claim 1, wherein the method is characterized by: The premixed liquid is prepared by the following method: Add the monomers and cross-linking agents to water, mix after stirring, then add the dispersants, defoaming agents, modified silicon carbide powder and sintering aids, then add tetramethylammonium hydroxide, ball mix for 2h, then vacuum defoam to obtain the premixed liquid, then add the catalyst and initiator to obtain the premixed liquid.

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