Preparation method of high-precision silicon carbide combined guide rail

Abstract

The invention relates to a preparation method of a high-precision silicon carbide combined guide rail, and belongs to the technical field of ceramic guide rail preparation, and the preparation method comprises the following steps: mixing modified reinforced silicon carbide powder, a compound dispersant and deionized water, and then carrying out ball milling to obtain a suspended matter; adding the pretreated composite gel into the suspended matter, and uniformly stirring to obtain ceramic slurry; after the inner side wall of a mold is coated with a release agent, ceramic slurry is injected into the mold, a green body is obtained after standing forming and demolding drying, and the high-precision silicon carbide combined guide rail is obtained through reactive sintering, accurate grinding and polishing. According to the technical scheme, hydroxylated silicon carbide powder and polydopamine coated carbon black are mixed to form enhanced silicon carbide powder, then the silane coupling agent is grafted, modified enhanced silicon carbide powder is prepared, and the mechanical performance and thermal stability of the combined guide rail are effectively improved; the composite gel improves the compactness and the dimensional stability of the combined guide rail, and overall improves the comprehensive performance of the combined guide rail.

Description

Technical Field

[0001] This invention belongs to the field of ceramic guide rail manufacturing technology, specifically, it relates to a method for manufacturing high-precision silicon carbide composite guide rails. Background Technology

[0002] With the development of semiconductor manufacturing, high-end optical processing, and ultra-precision measurement, ultra-precision equipment places higher demands on the accuracy, thermal stability, and long-term durability of moving parts. Traditional precision guideways are mostly made of metal materials (such as aluminum alloys and stainless steel), but metal materials have high coefficients of thermal expansion and are easily deformed by temperature, making it difficult to meet sub-micron or even nanometer-level precision requirements. In contrast, silicon carbide (SiC) ceramics, due to their low coefficient of thermal expansion, high hardness, excellent wear resistance, and good chemical stability, have become ideal materials for manufacturing high-precision guideways. Currently, silicon carbide composite guideways mainly employ processes such as cold isostatic pressing, slip casting, and pressure filtration molding, but these methods suffer from high equipment costs, low raw material utilization, and difficulties in molding complex structures. While gel casting, as a low-cost technology that can achieve near-net-shape molding of complex structures, has development potential, traditional systems use toxic monomers (such as acrylamide), have complex processes, and are prone to cracking and deformation during debinding, limiting their widespread application.

[0003] In existing technologies, high-precision silicon carbide composite guide rails are mostly modified by adding sintering aids (such as Al2O3, Y2O3, etc.) to silicon carbide. However, this easily introduces impurity phases, affecting the purity and density of the material, which in turn causes dimensional deformation and a decrease in mechanical properties. Furthermore, modifying silicon carbide with nanomaterials (such as silicon dioxide, graphene, etc.) results in problems such as weak interfacial bonding and uneven dispersion, leading to low green strength, easy deformation, and affecting the final precision of the material. Therefore, there is an urgent need to develop a composite guide rail with high precision, high mechanical strength, and excellent dimensional stability to overcome the bottlenecks in materials, processes, and performance of existing technologies and meet the stringent requirements of high-end equipment for core components. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing high-precision silicon carbide composite guide rails. The method involves mixing modified and reinforced silicon carbide powder, a compound dispersant, and deionized water, followed by ball milling to obtain a suspension. A pre-treated composite gelling agent is added to the suspension in step S1, and after stirring evenly, a ceramic slurry is obtained. A release agent is coated onto the inner wall of a mold, and the ceramic slurry from step S2 is injected into the mold. After static molding, demolding, and drying, a green body is obtained. This green body is then subjected to reaction sintering, followed by fine grinding and polishing to obtain a high-precision silicon carbide composite guide rail. The modified silicon carbide powder and compound dispersant can effectively improve the mechanical properties of the composite guide rail, increase the purity and density of the green body, and the composite gelling agent helps the ceramic slurry to quickly and uniformly transform into a three-dimensional network structure with sufficient strength in the mold, thereby obtaining a green body with high dimensional accuracy and improving the overall performance of the silicon carbide composite guide rail.

[0005] The technical problem to be solved by this invention is as follows: In the prior art, most high-precision silicon carbide composite guide rails are modified by adding sintering aids (such as Al2O3, Y2O3, etc.), but this easily introduces impurity phases, affecting the purity and density of the material, and thus causing dimensional deformation and a decrease in mechanical properties; and modifying silicon carbide with nanomaterials (such as silicon dioxide, graphene, etc.) has problems such as weak interfacial bonding and uneven dispersion, resulting in low green strength, easy deformation, and affecting the final precision of the material.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for manufacturing a high-precision silicon carbide composite guide rail includes the following steps: S1: Mix modified and reinforced silicon carbide powder, compound dispersant and deionized water, and then ball mill to obtain a suspension; S2: Add the pretreated composite gel to the suspension in step S1, stir evenly, and obtain ceramic slurry; S3: After coating the inner wall of the mold with a release agent, the ceramic slurry from step S2 is injected into the mold, allowed to stand and form, and then demolded and dried to obtain a green body. After reaction sintering, it is then subjected to fine grinding and polishing to obtain a high-precision silicon carbide composite guide rail.

[0007] Further, in step S1, the mass ratio of the modified and reinforced silicon carbide powder, the compound dispersant, and the deionized water is 0.9-1.1:0.008-0.015:0.3-0.4.

[0008] Further, in step S1, the specific process parameters for ball milling are as follows: using zirconia balls as grinding balls, controlling the mass ratio of zirconia balls to modified reinforced silicon carbide powder to be 4:1 (i.e., ball-to-material ratio of 4:1), the ball milling speed to be 200-300 r / min, and the ball milling time to be 6-8 h.

[0009] Further, in step S1, the compound dispersant is composed of tetramethylammonium hydroxide and sodium polyacrylate mixed in a mass ratio of 1:2-3.

[0010] Further, in step S1, the method for preparing the modified and reinforced silicon carbide powder includes the following steps: The modified silicon carbide powder, silane coupling agent, ethanol and deionized water were mixed evenly and then stirred in a water bath. After the reaction was completed, the mixture was centrifuged, washed with deionized water, and finally vacuum dried to obtain the modified silicon carbide powder.

[0011] During the above reaction process, the surface of the enhanced silicon carbide powder has hydroxyl groups. After the silane coupling agent is hydrolyzed, silanol groups are generated. The silanol groups on the silane coupling agent can react and combine with the hydroxyl groups on the surface of the enhanced silicon carbide powder, grafting the silane coupling agent onto the surface of the enhanced silicon carbide powder, and finally obtaining modified enhanced silicon carbide powder.

[0012] Furthermore, the mass ratio of the mixed solution of the enhanced silicon carbide powder, silane coupling agent, ethanol and deionized water is 9.8-10.2:0.1-0.3:50-60.

[0013] Furthermore, the silane coupling agent is N-aminoethyl-γ-aminopropyltrimethoxysilane.

[0014] Furthermore, the enhanced silicon carbide powder is composed of hydroxylated silicon carbide powder and polydopamine-coated carbon black mixed in a mass ratio of 0.9-1.1:0.3-0.4.

[0015] Furthermore, the stirring reaction is carried out at a temperature of 60-70°C for 4-6 hours.

[0016] Furthermore, the method for preparing the hydroxylated silicon carbide powder includes the following steps: Silicon carbide powder was heated to 950℃ at a heating rate of 5℃ / min and held at that temperature for 2 hours. After oxidation, it was cooled to room temperature to obtain pre-oxidized silicon carbide powder. The pre-oxidized silicon carbide powder, ethanol, deionized water and concentrated hydrochloric acid were mixed and ball-milled at 180 r / min for 6 hours. After ball milling, it was centrifuged at 4000 rpm for 5 minutes, washed three times with deionized water, and finally vacuum dried at 60℃ for 12 hours to obtain hydroxylated silicon carbide powder.

[0017] Furthermore, the mass ratio of the pre-oxidized silicon carbide powder, ethanol, deionized water, and concentrated hydrochloric acid is 1:0.2:1:0.1.

[0018] Furthermore, the preparation method of the polydopamine-coated carbon black includes the following steps: Carbon black was added to a Tris-HCl buffer solution and ultrasonically dispersed. Dopamine hydrochloride was then added, and the mixture was stirred in a water bath. After the reaction was completed, the mixture was centrifuged, washed with deionized water, and finally vacuum dried to obtain polydopamine-coated carbon black.

[0019] During the above reaction, dopamine hydrochloride undergoes an oxidative self-polymerization reaction to generate polydopamine, which can be adsorbed onto the surface of carbon black, finally resulting in polydopamine-coated carbon black.

[0020] Furthermore, the mass ratio of carbon black, Tris-HCl buffer solution, and dopamine hydrochloride is 4.8-5.2:170-190:0.3-0.4.

[0021] Furthermore, the ultrasonic dispersion time is 25-35 minutes.

[0022] Furthermore, the temperature of the stirring reaction is 45-55℃, and the time is 25-35 min.

[0023] Furthermore, the vacuum drying temperature is 50-60℃, and the time is 12 hours.

[0024] Further, in step S2, the mass ratio of the pretreated composite gel agent to the suspension is 1-1.5:10.

[0025] Further, in step S2, the specific steps for the pretreatment of the composite gel agent are as follows: The composite gelling agent is added to a sodium hydroxide solution, and the pH of the system is adjusted to 9-10. Then, it is heated to 65-75℃ and stirred until completely dissolved. Finally, it is cooled to 30-40℃ to obtain the pretreated composite gelling agent.

[0026] Furthermore, the composite gelling agent is composed of poly(isobutylene-alt-maleic anhydride) and gelatin in a mass ratio of 0.7-0.8:0.4-0.5.

[0027] Furthermore, in step S3, the mold is a stainless steel mold made of SUS304.

[0028] Further, in step S3, the mass of the release agent is 0.2-0.3% of the mass of the ceramic slurry.

[0029] Furthermore, in step S3, the release agent is dimethyl silicone oil.

[0030] Furthermore, in step S3, the temperature for demolding and drying is 50-60℃, and the time is 24-28h.

[0031] Furthermore, in step S3, the reaction sintering process specifically involves: placing the green blank into a high-temperature sintering furnace for silicon diffusion reaction sintering, controlling the mass ratio of green blank to metallic silicon to be 1:0.6-0.8, heating to 1500-1600℃ at a heating rate of 10-20℃ / min, and holding at that temperature for 3-5 hours.

[0032] The beneficial effects of this invention are: (1) In the technical solution of this invention, modified and reinforced silicon carbide powder, compound dispersant and deionized water are mixed and then ball-milled to obtain a suspension; wherein, the modified and reinforced silicon carbide powder is obtained by grafting and reinforcing silicon carbide powder with silane coupling agent, and the reinforced silicon carbide powder is composed of hydroxylated silicon carbide powder and polydopamine-coated carbon black. The two have a synergistic effect, which can better improve the mechanical properties and thermal stability of silicon carbide composite guide rails. In addition, polydopamine-coated carbon black can increase the bonding force between carbon black and hydroxylated silicon carbide powder, and improve the dispersibility of silicon carbide powder and carbon black, further improving the mechanical properties and thermal conductivity of silicon carbide composite guide rails. In addition, during the high-temperature sintering process, the surface Organic dopamine molecules act as a carbon source, reacting with molten silicon to form silicon carbide in situ, increasing the purity and density of the composite guide rails. Silane coupling agents not only improve the dispersibility of the enhanced silicon carbide powder but also provide amino groups, which can crosslink with the subsequently added composite gelling agent, making the prepared green body structure more uniform and further increasing the density, mechanical properties, and dimensional stability of the composite guide rails. The composite dispersant is composed of a mixture of tetramethylammonium hydroxide and sodium polyacrylate, which work synergistically to effectively improve the dispersibility and flowability of the enhanced silicon carbide powder, prevent its agglomeration, and reduce its viscosity, further improving the dimensional stability and sintering density of the silicon carbide composite guide rails.

[0033] (2) In the technical solution of the present invention, a ceramic slurry is obtained by adding the pretreated composite gelling agent to the suspension in step S1 and stirring it evenly; the composite gelling agent is composed of poly(isobutylene-alt-maleic anhydride) and gelatin; the two play a synergistic role, which not only enables the ceramic slurry to be quickly and evenly transformed into a three-dimensional network structure with sufficient strength in the mold to obtain a green body with high dimensional accuracy, but also makes the green body have high mechanical strength, which makes it less prone to collapse and cracking during demolding, and facilitates subsequent drying, further improving the mechanical properties and dimensions of the silicon carbide composite guide rail. The stability and density are increased. In addition, poly(isobutylene-alt-maleic anhydride) and gelatin are both non-toxic or low-toxic polymer materials with good environmental protection properties. They can form a gel network structure without the need for initiators and crosslinking agents, which is conducive to the green manufacturing of silicon carbide composite guide rails. After coating the inner wall of the mold with a release agent, the ceramic slurry in step S2 is injected into the mold. After static molding, demolding and drying, a green body is obtained. After reaction sintering, fine grinding and polishing are performed to obtain a high-precision silicon carbide composite guide rail, which improves the overall performance of the composite guide rail.

[0034] (3) In the technical solution of the present invention, modified and enhanced silicon carbide powder, compound dispersant and deionized water are mixed and ball-milled, then pretreated composite gel agent is added, stirred evenly, injected into a mold coated with release agent, allowed to stand to form, demolded and dried, sintered by reaction, and then finely ground and polished to finally obtain high-precision silicon carbide composite guide rail; the high-precision silicon carbide composite guide rail has good mechanical properties, thermal conductivity and thermal stability, and high density and purity, and good overall comprehensive performance. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] The specific parameters of the raw materials used in this invention are as follows: Silicon carbide powder, particle size / mesh: 1250 mesh, provided by Nangong Jiuxin New Material Technology Co., Ltd.; Carbon black, particle diameter: 20nm, provided by Chengdu Jingyi New Material Co., Ltd.; Sodium polyacrylate, CAS No.: 9003-04-7, product number: 016546589, provided by Shanghai Titan Technology Co., Ltd.; Poly(isobutylene-alt-maleic anhydride), CAS No.: 26426-80-2, product number: P922142, provided by Shanghai Maclean Biochemical Technology Co., Ltd.; Gelatin, CAS No.: 9000-70-8, product number: G810472, provided by Shanghai Maclean Biochemical Technology Co., Ltd.; Dimethyl silicone oil, CAS No.: 63148-62-9, product number: D817599, provided by Shanghai Maclean Biochemical Technology Co., Ltd.

[0037] The preparation method of hydroxylated silicon carbide powder includes the following steps: Silicon carbide powder was heated to 950℃ at a heating rate of 5℃ / min and held at that temperature for 2 hours. After oxidation, it was cooled to room temperature to obtain pre-oxidized silicon carbide powder. The pre-oxidized silicon carbide powder, ethanol, deionized water and concentrated hydrochloric acid were mixed in a mass ratio of 1:0.2:1:0.1 and ball-milled at 180 r / min for 6 hours. Zirconia balls were used as grinding balls, and the mass ratio of zirconia balls to pre-oxidized silicon carbide powder was controlled at 3:1 (i.e., ball-to-powder ratio of 3:1). After ball milling, it was centrifuged at 4000 rpm for 5 minutes and washed three times with deionized water (each time the mass of deionized water was 3 times the mass of the above deionized water). Finally, it was vacuum dried at 60℃ for 12 hours to obtain hydroxylated silicon carbide powder.

[0038] Example 1 A method for manufacturing a high-precision silicon carbide composite guide rail includes the following steps: S1: The modified reinforced silicon carbide powder, the compound dispersant, and deionized water were mixed in a mass ratio of 0.9:0.008:0.3, and then ball-milled. Zirconia balls were used as grinding balls, and the mass ratio of zirconia balls to modified reinforced silicon carbide powder was controlled at 4:1 (i.e., ball-to-material ratio of 4:1). The ball milling speed was 200 r / min, and the ball milling time was 8 h. After the ball milling was completed, a suspension was obtained. The compound dispersant was composed of tetramethylammonium hydroxide and sodium polyacrylate mixed in a mass ratio of 1:2. The preparation method of modified and reinforced silicon carbide powder includes the following steps: The modified reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyltrimethoxysilane, ethanol, and deionized water were mixed in a mass ratio of 9.8:0.1:50. The mixture was stirred at 400 rpm for 6 hours in a water bath at 60°C. After the reaction, the mixture was centrifuged at 3000 rpm for 10 minutes and washed three times with deionized water (each time the mass of deionized water was 30% of the mass of the ethanol and deionized water mixture). Finally, the mixture was vacuum dried at 55°C for 12 hours to obtain the modified reinforced silicon carbide powder. The modified reinforced silicon carbide powder was composed of hydroxylated silicon carbide powder and polydopamine-coated carbon black mixed in a mass ratio of 0.9:0.3. The preparation method of polydopamine-coated carbon black includes the following steps: The carbon black, Tris-HCl buffer solution, and dopamine hydrochloride were mixed in a mass ratio of 4.8:170:0.3. The carbon black was added to 0.05M Tris-HCl buffer solution (pH=8.5) and ultrasonically dispersed for 25 min (ultrasonic power 100W, ultrasonic frequency 40kHz). Then, dopamine hydrochloride was added, and the mixture was stirred at 300 rpm for 35 min in a water bath at 45℃. After the reaction was completed, the mixture was centrifuged at 3000 rpm for 10 min, washed three times with deionized water (each time the mass of deionized water was 20% of the mass of Tris-HCl buffer solution), and finally vacuum dried at 50℃ for 12 h to obtain polydopamine-coated carbon black. S2: According to the mass ratio of pretreated composite gel agent to suspension of 1:10, add pretreated composite gel agent to suspension of step S1, stir evenly, and obtain ceramic slurry; The specific steps for pretreatment of the composite gel are as follows: The composite gelling agent was added to a 0.01M sodium hydroxide solution (the mass of the composite gelling agent was 5% of the mass of the sodium hydroxide solution), and the pH of the system was adjusted to 9. Then, the solution was heated to 65°C and stirred until completely dissolved. The solution was then cooled to 30°C to obtain a pretreated composite gelling agent. The composite gelling agent was composed of poly(isobutylene-alt-maleic anhydride) and gelatin in a mass ratio of 0.7:0.4. S3: After coating the inner wall of the mold (SUS304 stainless steel mold) with dimethyl silicone oil (the mass of dimethyl silicone oil is 0.2% of the mass of ceramic slurry), the ceramic slurry from step S2 is injected into the mold (SUS304 stainless steel mold), and the mold is allowed to stand and form. After demolding and drying, the demolding and drying temperature is 50℃ and the time is 28h to obtain a green body. The green body is then subjected to reaction sintering. The reaction sintering process is as follows: the green body is placed in a high-temperature sintering furnace for silicon diffusion reaction sintering. The mass ratio of green body to metallic silicon is controlled at 1:0.6. The temperature is raised to 1500℃ at a heating rate of 10℃ / min and held for 5h. Then, fine grinding and polishing are performed to obtain a high-precision silicon carbide composite guide rail.

[0039] Example 2 A method for manufacturing a high-precision silicon carbide composite guide rail includes the following steps: S1: The modified reinforced silicon carbide powder, the compound dispersant, and deionized water were mixed in a mass ratio of 1:0.012:0.35, and then ball-milled. Zirconia balls were used as grinding balls, and the mass ratio of zirconia balls to modified reinforced silicon carbide powder was controlled at 4:1 (i.e., ball-to-material ratio of 4:1). The ball milling speed was 250 r / min, and the ball milling time was 7 h. After the ball milling was completed, a suspension was obtained. The compound dispersant was composed of tetramethylammonium hydroxide and sodium polyacrylate mixed in a mass ratio of 1:2.5. The preparation method of modified and reinforced silicon carbide powder includes the following steps: The modified reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyltrimethoxysilane, ethanol, and deionized water were mixed in a mass ratio of 10:0.2:55. The mixture was stirred at 500 rpm for 5 hours in a water bath at 65°C. After the reaction, the mixture was centrifuged at 3500 rpm for 8 minutes and washed three times with deionized water (each time the mass of deionized water was 30% of the mass of the ethanol and deionized water mixture). Finally, the mixture was vacuum dried at 60°C for 12 hours to obtain the modified reinforced silicon carbide powder. The modified reinforced silicon carbide powder was composed of hydroxylated silicon carbide powder and polydopamine-coated carbon black mixed in a mass ratio of 1:0.35. The preparation method of polydopamine-coated carbon black includes the following steps: The carbon black, Tris-HCl buffer solution, and dopamine hydrochloride were mixed in a mass ratio of 5:180:0.35. The carbon black was added to 0.05M Tris-HCl buffer solution (pH=8.5) and ultrasonically dispersed for 30 min (ultrasonic power 100W, ultrasonic frequency 40kHz). Then, dopamine hydrochloride was added, and the mixture was stirred at 400 rpm in a 50℃ water bath for 30 min. After the reaction was completed, the mixture was centrifuged at 3500 rpm for 8 min, washed three times with deionized water (each time the mass of deionized water was 20% of the mass of Tris-HCl buffer solution), and finally vacuum dried at 55℃ for 12 h to obtain polydopamine-coated carbon black. S2: According to the mass ratio of pretreated composite gel agent to suspension of 1.2:10, add the pretreated composite gel agent to the suspension of step S1, stir evenly, and then obtain ceramic slurry; The specific steps for pretreatment of the composite gel are as follows: The composite gelling agent was added to a 0.01M sodium hydroxide solution (the mass of the composite gelling agent was 8% of the mass of the sodium hydroxide solution), and the pH of the system was adjusted to 9.5. Then, the solution was heated to 70°C and stirred until completely dissolved. The solution was then cooled to 35°C to obtain a pretreated composite gelling agent. The composite gelling agent was composed of poly(isobutylene-alt-maleic anhydride) and gelatin in a mass ratio of 0.75:0.45. S3: After coating the inner wall of the mold (SUS304 stainless steel mold) with dimethyl silicone oil (the mass of dimethyl silicone oil is 0.25% of the mass of ceramic slurry), the ceramic slurry from step S2 is injected into the mold (SUS304 stainless steel mold), and the mold is allowed to stand and form. After demolding and drying, the demolding and drying temperature is 55℃ and the time is 26h to obtain a green body. The green body is then subjected to reaction sintering. The reaction sintering process is as follows: the green body is placed in a high-temperature sintering furnace for silicon diffusion reaction sintering. The mass ratio of green body to metallic silicon is controlled at 1:0.7. The temperature is raised to 1550℃ at a heating rate of 15℃ / min and held for 4h. Then, fine grinding and polishing are performed to obtain a high-precision silicon carbide composite guide rail.

[0040] Example 3 A method for manufacturing a high-precision silicon carbide composite guide rail includes the following steps: S1: The modified reinforced silicon carbide powder, the compound dispersant, and deionized water were mixed in a mass ratio of 1.1:0.015:0.4, and then ball-milled. Zirconia balls were used as grinding balls, and the mass ratio of zirconia balls to modified reinforced silicon carbide powder was controlled at 4:1 (i.e., ball-to-material ratio of 4:1). The ball milling speed was 300 r / min, and the ball milling time was 6 h. After the ball milling was completed, a suspension was obtained. The compound dispersant was composed of tetramethylammonium hydroxide and sodium polyacrylate mixed in a mass ratio of 1:3. The preparation method of modified and reinforced silicon carbide powder includes the following steps: The modified reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyltrimethoxysilane, ethanol, and deionized water were mixed in a mass ratio of 10.2:0.3:60. The mixture was stirred at 600 rpm for 4 hours in a water bath at 70°C. After the reaction, the mixture was centrifuged at 4000 rpm for 5 minutes and washed three times with deionized water (each time the mass of deionized water was 30% of the mass of the ethanol and deionized water mixture). Finally, the mixture was vacuum dried at 65°C for 12 hours to obtain the modified reinforced silicon carbide powder. The modified reinforced silicon carbide powder was composed of hydroxylated silicon carbide powder and polydopamine-coated carbon black mixed in a mass ratio of 1.1:0.4. The preparation method of polydopamine-coated carbon black includes the following steps: The carbon black, Tris-HCl buffer solution, and dopamine hydrochloride were mixed in a mass ratio of 5.2:190:0.4. The carbon black was added to 0.05M Tris-HCl buffer solution (pH=8.5) and ultrasonically dispersed for 35 min (ultrasonic power 100W, ultrasonic frequency 40kHz). Then, dopamine hydrochloride was added, and the mixture was stirred at 500 rpm for 25 min in a water bath at 55℃. After the reaction was completed, the mixture was centrifuged at 4000 rpm for 5 min, washed three times with deionized water (each time the mass of deionized water was 20% of the mass of Tris-HCl buffer solution), and finally vacuum dried at 60℃ for 12 h to obtain polydopamine-coated carbon black. S2: According to the mass ratio of pretreated composite gel agent to suspension of 1.5:10, add pretreated composite gel agent to suspension of step S1, stir evenly, and then obtain ceramic slurry. The specific steps for pretreatment of the composite gel are as follows: The composite gelling agent was added to a 0.01M sodium hydroxide solution (the mass of the composite gelling agent was 10% of the mass of the sodium hydroxide solution), and the pH of the system was adjusted to 10. Then, the solution was heated to 75°C and stirred until completely dissolved. Finally, the solution was cooled to 40°C to obtain a pretreated composite gelling agent. The composite gelling agent was composed of poly(isobutylene-alt-maleic anhydride) and gelatin mixed in a mass ratio of 0.8:0.5. S3: After coating the inner wall of the mold (SUS304 stainless steel mold) with dimethyl silicone oil (the mass of dimethyl silicone oil is 0.3% of the mass of ceramic slurry), the ceramic slurry from step S2 is injected into the mold (SUS304 stainless steel mold), and the mold is allowed to stand and form. After demolding and drying, the demolding and drying temperature is 60℃ and the time is 24h to obtain a green body. The green body is then subjected to reaction sintering. The reaction sintering process is as follows: the green body is placed in a high-temperature sintering furnace for silicon diffusion reaction sintering. The mass ratio of green body to metallic silicon is controlled at 1:0.8. The temperature is raised to 1600℃ at a heating rate of 20℃ / min and held for 3h. Then, fine grinding and polishing are performed to obtain a high-precision silicon carbide composite guide rail.

[0041] Comparative Example 1 The difference between this comparative example and Example 3 is that, in the preparation of the high-precision silicon carbide composite guide rail, in step S1, the compound dispersant is replaced by tetramethylammonium hydroxide in equal mass, while the remaining steps and raw materials are the same as in Example 3. S1: The modified reinforced silicon carbide powder, tetramethylammonium hydroxide and deionized water were mixed in a mass ratio of 1.1:0.015:0.4, and then ball-milled. Zirconia balls were used as grinding balls, and the mass ratio of zirconia balls to modified reinforced silicon carbide powder was controlled at 4:1 (i.e. ball-to-material ratio of 4:1). The ball milling speed was 300 r / min and the ball milling time was 6 h. After the ball milling was completed, a suspension was obtained.

[0042] Comparative Example 2 The difference between this comparative example and Example 3 is that, in the preparation of the high-precision silicon carbide composite guide rail, in step S1, the compound dispersant is replaced by sodium polyacrylate in equal mass, while the remaining steps and raw materials are the same as in Example 3. S1: The modified reinforced silicon carbide powder, sodium polyacrylate and deionized water were mixed according to the mass ratio of 1.1:0.015:0.4, and then ball-milled. Zirconia balls were used as grinding balls, and the mass ratio of zirconia balls to modified reinforced silicon carbide powder was controlled at 4:1 (i.e. ball-to-material ratio of 4:1). The ball milling speed was 300 r / min and the ball milling time was 6 h. After the ball milling was completed, the suspension was obtained.

[0043] Comparative Example 3 The difference between this comparative example and Example 3 is that, in the preparation of the high-precision silicon carbide composite guide rail, in step S1, the reinforcing silicon carbide powder is composed of a mixture of hydroxylated silicon carbide powder and carbon black, while the remaining steps and raw materials are the same as in Example 3. The preparation method of modified and reinforced silicon carbide powder includes the following steps: The modified reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyltrimethoxysilane, ethanol, and deionized water were mixed in a mass ratio of 10.2:0.3:60. The mixture was stirred at 600 rpm for 4 hours in a water bath at 70°C. After the reaction, the mixture was centrifuged at 4000 rpm for 5 minutes and washed three times with deionized water (each time the mass of deionized water was 30% of the mass of the ethanol and deionized water mixture). Finally, the mixture was vacuum dried at 65°C for 12 hours to obtain the modified reinforced silicon carbide powder. The modified reinforced silicon carbide powder was composed of hydroxylated silicon carbide powder and carbon black mixed in a mass ratio of 1.1:0.4.

[0044] Comparative Example 4 The difference between this comparative example and Example 3 is that, in the preparation of the high-precision silicon carbide composite guide rail, in step S1, the reinforcing silicon carbide powder is replaced with hydroxylated silicon carbide powder, while the remaining steps and raw materials are the same as in Example 3. The preparation method of modified and reinforced silicon carbide powder includes the following steps: The modified and reinforced silicon carbide powder was prepared by mixing hydroxylated silicon carbide powder, N-aminoethyl-γ-aminopropyltrimethoxysilane, ethanol, and deionized water in a mass ratio of 10.2:0.3:60. The mixture was stirred at 600 rpm for 4 hours in a water bath at 70°C. After the reaction was completed, the mixture was centrifuged at 4000 rpm for 5 minutes and washed three times with deionized water (each time the mass of deionized water was 30% of the mass of the ethanol and deionized water mixture). Finally, the mixture was vacuum dried at 65°C for 12 hours to obtain the modified and reinforced silicon carbide powder.

[0045] Comparative Example 5 The difference between this comparative example and Example 3 is that, in the preparation of the high-precision silicon carbide composite guide rail, in step S2, the composite gelling agent is replaced by poly(isobutylene-alt-maleic anhydride) by the same mass, while the remaining steps and raw materials are the same as in Example 3. S2: According to the mass ratio of pretreated poly(isobutylene-alt-maleic anhydride) to suspension of 1.5:10, add pretreated poly(isobutylene-alt-maleic anhydride) to suspension of step S1, stir evenly, and obtain ceramic slurry; The specific steps for pretreatment of the composite gel are as follows: Poly(isobutylene-alt-maleic anhydride) was added to a 0.01M sodium hydroxide solution (the mass of poly(isobutylene-alt-maleic anhydride) was 10% of the mass of the sodium hydroxide solution), and the pH of the system was adjusted to 10. Then the mixture was heated to 75°C and stirred until completely dissolved. Finally, it was cooled to 40°C to obtain pretreated poly(isobutylene-alt-maleic anhydride).

[0046] Comparative Example 6 The difference between this comparative example and Example 3 is that, in the preparation of the high-precision silicon carbide composite guide rail, in step S2, the composite gelling agent is replaced with gelatin by the same mass, while the remaining steps and raw materials are the same as in Example 3. S2: According to the mass ratio of pretreated gelatin to suspension of 1.5:10, add gelatin to suspension of 1, stir evenly to obtain ceramic slurry; The specific steps for pretreatment of the composite gel are as follows: Gelatin was added to a 0.01M sodium hydroxide solution (the mass of gelatin was 10% of the mass of sodium hydroxide solution), and the pH of the system was adjusted to 10. The solution was then heated to 75°C and stirred until completely dissolved. Finally, it was cooled to 40°C to obtain pretreated gelatin.

[0047] The high-precision silicon carbide composite guide rails prepared in Examples 1-3 and Comparative Examples 1-6 were tested for bulk density, compactness, flexural strength, and thermal conductivity. Density testing was performed according to GB / T 25995-2010 standard; compactness testing was conducted using a density analyzer; flexural strength testing was performed according to GB / T 6569-2006 standard; and thermal conductivity testing was performed according to GB / T 22588-2008 standard. The test results are shown in Table 1 below. Table 1 Performance parameters of high-precision silicon carbide composite guide rails As shown in Table 1 above, comparing Comparative Examples 1-4 and Example 3, it can be seen that replacing the compound dispersant with tetramethylammonium hydroxide or sodium polyacrylate, or using a mixture of hydroxylated silicon carbide powder and carbon black as the reinforcing silicon carbide powder, or replacing the reinforcing silicon carbide powder with hydroxylated silicon carbide powder as the reinforcing silicon carbide powder, resulted in a lower test result for the high-precision silicon carbide composite guide rail compared to Example 3. This indicates that the compound dispersant composed of tetramethylammonium hydroxide and sodium polyacrylate has a synergistic effect, which can not only improve the dispersibility and stability of the modified reinforcing silicon carbide powder, but also further improve the mechanical properties and density of the composite guide rail. The reinforcing silicon carbide powder composed of hydroxylated silicon carbide powder and polydopamine-coated carbon black can effectively enhance the dispersibility of silicon carbide powder and carbon black, further improve the mechanical and thermal properties of the silicon carbide composite guide rail, and increase its density. Comparison of Comparative Examples 5-6 and Example 3 shows that when the composite gelling agent is replaced by an equal mass of poly(isobutylene-alt-maleic anhydride) or gelatin, the test results of the high-precision silicon carbide composite guide rail are worse than those of Example 3. This indicates that the composite gelling agent composed of poly(isobutylene-alt-maleic anhydride) and gelatin can play a synergistic role, transforming the ceramic slurry into a three-dimensional cross-linked network, improving the mechanical strength and dimensional accuracy of the green body, further improving the mechanical properties and dimensional stability of the composite guide rail, and increasing its density.

[0048] As shown in Table 1 above, the high-precision silicon carbide composite guide rails prepared in Examples 1-3, compared to those prepared in Comparative Examples 1-6, achieved better performance. This was achieved by mixing modified and reinforced silicon carbide powder, a compound dispersant, and deionized water, ball milling to obtain a suspension, adding a pre-treated composite gelling agent to the suspension, stirring until homogeneous, obtaining a ceramic slurry, coating a mold with a release agent, injecting the ceramic slurry, allowing it to stand and form, demolding and drying to obtain a green body, followed by reaction sintering, fine grinding, and polishing. The high-precision silicon carbide composite guide rails prepared in Examples 1-3 met the performance requirements, while those prepared in Comparative Examples 1-6 did not. This indicates that the high-precision silicon carbide composite guide rails prepared in this invention have higher mechanical strength, purity, density, thermal stability, and dimensional stability, exhibiting better overall performance.

[0049] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0050] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined by the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for manufacturing high-precision silicon carbide composite guide rails, characterized in that, Includes the following steps: S1: Mix modified and reinforced silicon carbide powder, compound dispersant and deionized water, and then ball mill to obtain a suspension; S2: Add the pretreated composite gel to the suspension in step S1, stir evenly, and obtain ceramic slurry; S3: After coating the inner wall of the mold with a release agent, the ceramic slurry from step S2 is injected into the mold, allowed to stand and form, and then demolded and dried to obtain a green body. After reaction sintering, it is then subjected to fine grinding and polishing to obtain a high-precision silicon carbide composite guide rail.

2. The method for manufacturing a high-precision silicon carbide composite guide rail according to claim 1, characterized in that, In step S1, the mass ratio of the modified and reinforced silicon carbide powder, the compound dispersant, and the deionized water is 0.9-1.1:0.008-0.015:0.3-0.

4.

3. The method for manufacturing a high-precision silicon carbide composite guide rail according to claim 1, characterized in that, In step S1, the compound dispersant is composed of tetramethylammonium hydroxide and sodium polyacrylate mixed in a mass ratio of 1:2-3.

4. The method for manufacturing a high-precision silicon carbide composite guide rail according to claim 1, characterized in that, In step S1, the method for preparing the modified and reinforced silicon carbide powder includes the following steps: The modified silicon carbide powder, silane coupling agent, ethanol and deionized water were mixed evenly and then stirred in a water bath. After the reaction was completed, the mixture was centrifuged, washed with deionized water, and finally vacuum dried to obtain the modified silicon carbide powder.

5. The method for manufacturing a high-precision silicon carbide composite guide rail according to claim 4, characterized in that, The silane coupling agent is N-aminoethyl-γ-aminopropyltrimethoxysilane.

6. The method for manufacturing a high-precision silicon carbide composite guide rail according to claim 4, characterized in that, The enhanced silicon carbide powder is composed of hydroxylated silicon carbide powder and polydopamine-coated carbon black mixed in a mass ratio of 0.9-1.1:0.3-0.

4.

7. The method for manufacturing a high-precision silicon carbide composite guide rail according to claim 6, characterized in that, The preparation method of the polydopamine-coated carbon black includes the following steps: Carbon black was added to a Tris-HCl buffer solution and ultrasonically dispersed. Dopamine hydrochloride was then added, and the mixture was stirred in a water bath. After the reaction was completed, the mixture was centrifuged, washed with deionized water, and finally vacuum dried to obtain polydopamine-coated carbon black.

8. The method for manufacturing a high-precision silicon carbide composite guide rail according to claim 1, characterized in that, In step S2, the specific steps for the pretreatment of the composite gel agent are as follows: The composite gelling agent is added to a sodium hydroxide solution, and the pH of the system is adjusted to 9-10. Then, it is heated to 65-75℃ and stirred until completely dissolved. Finally, it is cooled to 30-40℃ to obtain the pretreated composite gelling agent.

9. The method for manufacturing a high-precision silicon carbide composite guide rail according to claim 8, characterized in that, The composite gelling agent is composed of poly(isobutylene-alt-maleic anhydride) and gelatin in a mass ratio of 0.7-0.8:0.4-0.

5.

10. The method for manufacturing a high-precision silicon carbide composite guide rail according to claim 1, characterized in that, In step S3, the reaction sintering process specifically involves: placing the green blank into a high-temperature sintering furnace for silicon diffusion reaction sintering, controlling the mass ratio of green blank to metallic silicon to be 1:0.6-0.8, heating to 1500-1600℃ at a heating rate of 10-20℃ / min, and holding at that temperature for 3-5 hours.

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