A high-precision silicon carbide combined guide rail preparation method

Abstract

The application relates to a high-precision silicon carbide combined guide rail preparation method and belongs to the technical field of ceramic guide rail preparation. The method comprises the following steps: mixing modified reinforced silicon carbide powder, a compounded dispersant and deionized water, then performing ball milling to obtain a suspension; adding pretreated composite gel into the suspension, uniformly stirring and then obtaining ceramic slurry; coating a release agent on the inner side wall of a mold, pouring the ceramic slurry into the mold, standing for forming, demolding and drying to obtain a green body, performing reaction sintering, then performing fine grinding and polishing to obtain a high-precision silicon carbide combined guide rail. In the technical scheme, the modified reinforced silicon carbide powder is prepared by mixing hydroxylated silicon carbide powder and polydopamine-coated carbon black, and then grafting a silane coupling agent, so that the mechanical properties and thermal stability of the combined guide rail are effectively improved; the composite gel improves the compactness and size stability of the combined guide rail, and the comprehensive performance of the combined guide rail is overall improved.

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 the present application is to provide a high-precision silicon carbide combined guide rail preparation method, which comprises the following steps: mixing modified reinforced silicon carbide powder, compounded dispersant and deionized water, then ball milling to obtain a suspension; adding a pretreated composite gel agent to the suspension in step S1, stirring uniformly to obtain a ceramic slurry; coating a release agent on the inner side wall of the mold, then pouring the ceramic slurry in step S2 into the mold, standing and forming, demolding and drying to obtain a green body, then reaction sintering, fine grinding and polishing to obtain a high-precision silicon carbide combined guide rail; the modified silicon carbide powder and the compounded dispersant can improve the mechanical properties of the combined guide rail, improve the purity and density of the green body, and the composite gel agent helps the ceramic slurry in the mold to quickly and uniformly transform into a three-dimensional network structure with sufficient strength to obtain a green body with high dimensional precision, thereby improving the overall performance of the silicon carbide combined guide rail.

[0005] The technical problem to be solved by the present application is that in the prior art, high-precision silicon carbide combined guide rails mostly use sintering additives (such as Al2O3, Y2O3, etc.) to modify silicon carbide, but impurities are easily introduced, affecting the purity and density of the material, and causing size deformation and mechanical property degradation; and the modification of silicon carbide by nanomaterials (such as silicon dioxide, graphene, etc.) has problems such as weak interfacial bonding force and uneven dispersion, resulting in low green body strength and easy deformation, affecting the final accuracy of the material.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] A high-precision silicon carbide combined guide rail preparation method, comprising the following steps:

[0008] S1: mixing modified reinforced silicon carbide powder, compounded dispersant and deionized water, then ball milling to obtain a suspension;

[0009] S2: adding a pretreated composite gel agent to the suspension in step S1, stirring uniformly to obtain a ceramic slurry;

[0010] S3: coating a release agent on the inner side wall of the mold, then pouring the ceramic slurry in step S2 into the mold, standing and forming, demolding and drying to obtain a green body, then reaction sintering, fine grinding and polishing to obtain a high-precision silicon carbide combined guide rail.

[0011] Further, in step S1, the mass ratio of the modified reinforced silicon carbide powder, the compounded dispersant and the deionized water is 0.9-1.1:0.008-0.015:0.3-0.4.

[0012] 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.

[0013] Further, in step S1, the compound dispersant is composed of tetramethylammonium hydroxide and sodium polyacrylate mixed in a mass ratio of 1:2-3.

[0014] Further, in step S1, the method for preparing the modified and reinforced silicon carbide powder includes the following steps:

[0015] 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.

[0016] 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.

[0017] 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.

[0018] Furthermore, the silane coupling agent is N-aminoethyl-γ-aminopropyltrimethoxysilane.

[0019] 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.

[0020] Furthermore, the stirring reaction is carried out at a temperature of 60-70°C for 4-6 hours.

[0021] Furthermore, the preparation method of the hydroxylated silicon carbide powder includes the following steps:

[0022] 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.

[0023] Further, the mass ratio of the pre-oxidized silicon carbide powder, ethanol, deionized water, and concentrated hydrochloric acid is 1:0.2:1:0.1.

[0024] Further, the preparation method of the polydopamine-coated carbon black comprises the following steps:

[0025] The carbon black is added to the Tris-HCl buffer solution and ultrasonically dispersed, then hydrochloric acid dopamine is added, and then stirring reaction is performed in a water bath. After the reaction is completed, centrifugation is performed, deionized water is used for washing, and finally vacuum drying is performed to obtain the polydopamine-coated carbon black.

[0026] In the above reaction process, the hydrochloric acid dopamine undergoes an oxidation self-polymerization reaction to generate polydopamine, and the polydopamine can be adsorbed on the surface of the carbon black, and finally the polydopamine-coated carbon black is obtained.

[0027] Further, the mass ratio of the carbon black, the Tris-HCl buffer solution, and the hydrochloric acid dopamine is 4.8-5.2:170-190:0.3-0.4.

[0028] Further, the ultrasonic dispersion time is 25-35 min.

[0029] Further, the stirring reaction temperature is 45-55°C, and the time is 25-35 min.

[0030] Further, the vacuum drying temperature is 50-60°C, and the time is 12 h.

[0031] Further, in step S2, the mass ratio of the pretreated composite gel agent to the suspension is 1-1.5:10.

[0032] Further, in step S2, the specific steps of the pretreated composite gel agent are as follows:

[0033] The composite gel agent is added to the sodium hydroxide solution, and the pH value of the system is adjusted to 9-10, then heated to 65-75°C, stirred until completely dissolved, and then cooled to 30-40°C to obtain the pretreated composite gel agent.

[0034] Further, the composite gel agent is composed of poly(isobutylene-alt-maleic anhydride) and gelatin with a mass ratio of 0.7-0.8:0.4-0.5.

[0035] Further, in step S3, the mold is a stainless steel mold with a material of SUS304.

[0036] Further, in step S3, the release agent has a mass of 0.2-0.3% of the mass of the ceramic slurry.

[0037] Further, in step S3, the release agent is dimethyl silicone oil.

[0038] Further, in step S3, the temperature of the release drying is 50-60 DEG C, and the time is 24-28h.

[0039] Further, in step S3, the process of the reaction sintering is as follows: the green body is put into a high-temperature sintering furnace, silicon infiltration reaction sintering is carried out, the mass ratio of the green body and the silicon metal is controlled to be 1:0.6-0.8, the temperature is raised to 1500-1600 DEG C at a temperature rising rate of 10-20 DEG C / min, and the temperature is kept for 3-5h.

[0040] The beneficial effects of the present application are as follows:

[0041] (1) In the technical scheme of the present application, the modified reinforced silicon carbide powder, the compounded dispersant and the deionized water are mixed, and then ball milling is carried out to obtain a suspension; wherein the modified reinforced silicon carbide powder is prepared by grafting the silicon carbide powder with a silane coupling agent, the reinforced silicon carbide powder is composed of hydroxylated silicon carbide powder and polydopamine coated carbon black, and the two have a synergistic effect, which can better improve the mechanical properties and thermal stability of the silicon carbide combined guide rail, and the polydopamine coated carbon black can increase the bonding force between the carbon black and the hydroxylated silicon carbide powder, and improve the dispersity of the silicon carbide powder and the carbon black, further improve the mechanical properties and thermal conductivity of the silicon carbide combined guide rail, and in addition, in the high-temperature sintering process, the surface organic dopamine molecules act as a carbon source and react with molten silicon to form silicon carbide in situ, increasing the purity and density of the combined guide rail; the silane coupling agent not only improves the dispersity of the reinforced silicon carbide powder, but also provides amino groups, which can cross-link with the subsequent added composite gel agent, making the structure of the prepared green body more uniform, further increasing the density, mechanical properties and dimensional stability of the combined guide rail; the composite dispersant is composed of tetramethylammonium hydroxide and sodium polyacrylate, and the two have a synergistic effect, which can effectively improve the dispersity and fluidity of the reinforced silicon carbide powder, prevent its agglomeration, and reduce its viscosity, further improving the dimensional stability and sintering density of the silicon carbide combined guide rail.

[0042] (2) In the technical scheme of the present application, the pretreated composite gelatin is added to the suspension in step S1, stirred uniformly, and then the ceramic slurry is obtained; the composite gelatin is composed of poly(isoprene-alt-maleic anhydride) and gelatin; the two have a synergistic effect, not only can the ceramic slurry be quickly and uniformly converted into a three-dimensional network structure with sufficient strength in the mold to obtain a green body with high dimensional accuracy, but also the green body has high mechanical strength and is not easy to collapse and crack during demolding, facilitating subsequent drying, further improving the mechanical properties and dimensional stability of the silicon carbide combined guide rail, and increasing its density. In addition, poly(isoprene-alt-maleic anhydride) and gelatin are both non-toxic or low-toxic high molecular materials with good environmental friendliness, and do not need to add initiators and crosslinking agents to form a gel network structure, which is conducive to the green manufacturing of the silicon carbide combined guide rail. After coating a release agent on the inner side wall of the mold, the ceramic slurry in step S2 is injected into the mold, and the green body is obtained after static forming, demolding and drying. After reaction sintering, fine grinding and polishing processing, a high-precision silicon carbide combined guide rail is obtained, which improves the overall performance of the combined guide rail.

[0043] (3) In the technical scheme of the present application, the modified reinforced silicon carbide powder, the compounded dispersant and the deionized water are mixed, ball milled, and then the pretreated composite gelatin is added and stirred uniformly, and then injected into the mold coated with a release agent, and the green body is obtained after static forming, demolding and drying. After reaction sintering, fine grinding and polishing processing, a high-precision silicon carbide combined guide rail is obtained; the prepared high-precision silicon carbide combined guide rail has good mechanical properties, thermal conductivity and thermal stability, and high density and purity, and good overall performance. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0045] The specific parameters of the raw materials used in the present application are as follows:

[0046] Silicon carbide powder, particle size / mesh: 1250 mesh, provided by Nangong City Juxin New Material Technology Co., Ltd.; carbon black, particle diameter: 20 nm, provided by Chengdu Jingyi New Material Co., Ltd.; sodium polyacrylate, CAS No. 9003-04-7, product code: 016546589, Shanghai Titan Science and Technology Co., Ltd.; poly(isobutylene-alt-maleic anhydride), CAS No. 26426-80-2, product code: P922142, provided by Shanghai Macklin Biochemical Technology Co., Ltd.; gelatin, CAS No. 9000-70-8, product code: G810472, provided by Shanghai Macklin Biochemical Technology Co., Ltd.; dimethyl silicone oil, CAS No. 63148-62-9, product code: D817599, provided by Shanghai Macklin Biochemical Technology Co., Ltd.

[0047] The preparation method of the hydroxylated silicon carbide powder comprises the following steps:

[0048] The silicon carbide powder is heated to 950℃ at a heating rate of 5℃ / min and is kept for 2h of oxidation. After the end, it is cooled to room temperature to obtain the pre-oxidized silicon carbide powder. According to the mass ratio of pre-oxidized silicon carbide powder, ethanol, deionized water and concentrated hydrochloric acid is 1:0.2:1:0.1, the pre-oxidized silicon carbide powder, ethanol, deionized water and 37wt% concentrated hydrochloric acid are mixed, and ball milling is carried out at a speed of 180r / min for 6h, using zirconia balls as grinding balls, the mass ratio of zirconia balls to pre-oxidized silicon carbide powder is controlled to be 3:1 (i.e. the ball-to-material ratio is 3:1), after ball milling, centrifugation is carried out at a speed of 4000rpm for 5min, washing is carried out with deionized water for 3 times (each time the mass of deionized water is 3 times the mass of the above deionized water), and finally vacuum drying is carried out at 60℃ for 12h to obtain the hydroxylated silicon carbide powder.

[0049] Example 1

[0050] A high-precision silicon carbide combined guide rail preparation method comprises the following steps:

[0051] S1: according to the mass ratio of modified reinforced silicon carbide powder, compounded dispersant and deionized water is 0.9:0.008:0.3, the modified reinforced silicon carbide powder, compounded dispersant and deionized water are mixed, and then ball milling is carried out, using zirconia balls as grinding balls, the mass ratio of zirconia balls to modified reinforced silicon carbide powder is controlled to be 4:1 (i.e. the ball-to-material ratio is 4:1), the ball milling speed is 200r / min, the ball milling time is 8h, and after ball milling, the suspension is obtained, wherein the compounded dispersant is composed of tetramethylammonium hydroxide and sodium polyacrylate according to the mass ratio of 1:2;

[0052] The preparation method of the modified reinforced silicon carbide powder comprises the following steps:

[0053] According to the mass ratio of the reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyl trimethoxysilane, ethanol and deionized water mixed solution is 9.8:0.1:50, the reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyl trimethoxysilane, ethanol and deionized water mixed solution (the volume ratio of ethanol and deionized water is 5:1) is uniformly mixed, then stirred at 400 rpm in a water bath at 60°C for 6h, after the reaction is completed, centrifuged at 3000 rpm for 10 min, washed with deionized water for 3 times (each time the mass of deionized water is 30% of the mass of the ethanol and deionized water mixed solution), and finally vacuum dried at 55°C for 12h, to obtain the modified reinforced silicon carbide powder, wherein the reinforced silicon carbide powder is composed of hydroxylated silicon carbide powder and polydopamine coated carbon black with a mass ratio of 0.9:0.3;

[0054] The preparation method of the polydopamine coated carbon black comprises the following steps:

[0055] According to the mass ratio of carbon black, Tris-HCl buffer solution and dopamine hydrochloride is 4.8:170:0.3, the carbon black is added into 0.05M Tris-HCl buffer solution (pH=8.5) and ultrasonically dispersed for 25min (ultrasonic power is 100W, ultrasonic frequency is 40kHz), then dopamine hydrochloride is added, and then stirred at 300rpm in a water bath at 45°C for 35min, after the reaction is completed, centrifuged at 3000rpm for 10min, washed with deionized water for 3 times (each time the mass of deionized water is 20% of the mass of the Tris-HCl buffer solution), and finally vacuum dried at 50°C for 12h, to obtain the polydopamine coated carbon black;

[0056] S2: according to the mass ratio of the pretreated composite gel agent and the suspension is 1:10, the pretreated composite gel agent is added into the suspension in step S1, and stirred uniformly to obtain a ceramic slurry;

[0057] The specific steps of the pretreated composite gel agent are:

[0058] The composite gel agent is added into 0.01M sodium hydroxide solution (the mass of the composite gel agent is 5% of the mass of the sodium hydroxide solution), and the pH value of the system is adjusted to 9, then heated to 65°C and stirred until completely dissolved, and then cooled to 30°C to obtain the pretreated composite gel agent, wherein the composite gel agent is composed of poly(isobutylene-alt-maleic anhydride) and gelatin with a mass ratio of 0.7:0.4;

[0059] S3: After coating dimethyl silicone oil (the mass of dimethyl silicone oil is 0.2% of the mass of the ceramic slurry) on the inner wall of a mold (SUS304 stainless steel mold), the ceramic slurry in step S2 is injected into the mold (SUS304 stainless steel mold), and then static forming is performed. After demolding and drying, the temperature for demolding and drying is 50℃, and the time is 28h. A green body is obtained. After reaction sintering, the process of reaction sintering is as follows: the green body is placed in a high-temperature sintering furnace, siliconizing reaction sintering is performed, the mass ratio of the green body to silicon metal is controlled to be 1:0.6, the temperature is raised to 1500℃ at a temperature rising rate of 10℃ / min, and then the temperature is kept for 5h. After that, fine grinding and polishing are performed, and a high-precision silicon carbide combined guide rail is obtained.

[0060] Example 2

[0061] A method for preparing a high-precision silicon carbide combined guide rail, comprising the following steps:

[0062] S1: According to the mass ratio of modified reinforced silicon carbide powder, compounded dispersant and deionized water 1:0.012:0.35, the modified reinforced silicon carbide powder, the compounded dispersant and the deionized water are mixed, and then ball milling is performed. Zirconia balls are used as grinding balls. The mass ratio of zirconia balls to modified reinforced silicon carbide powder is controlled to be 4:1 (i.e. the ball-to-material ratio is 4:1). The ball milling speed is 250r / min. The ball milling time is 7h. After ball milling, a suspension is obtained. The compounded dispersant is composed of tetramethylammonium hydroxide and sodium polyacrylate according to the mass ratio of 1:2.5.

[0063] A method for preparing modified reinforced silicon carbide powder comprises the following steps:

[0064] According to the mass ratio of reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyl trimethoxysilane, ethanol and deionized water mixed solution 10:0.2:55, the reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyl trimethoxysilane, ethanol and deionized water mixed solution (the volume ratio of ethanol and deionized water is 5:1) are uniformly mixed, and then stirred at 500rpm in a water bath at 65℃ for 5h. After the reaction, centrifugation is performed at 3500rpm for 8min. The solution is washed with deionized water for 3 times (each time the mass of deionized water is 30% of the mass of the ethanol and deionized water mixed solution). Finally, vacuum drying is performed at 60℃ for 12h. Modified reinforced silicon carbide powder is obtained. The reinforced silicon carbide powder is composed of hydroxylated silicon carbide powder and polydopamine coated carbon black according to the mass ratio of 1:0.35.

[0065] A method for preparing polydopamine coated carbon black comprises the following steps:

[0066] According to the mass ratio of carbon black, Tris-HCl buffer solution, dopamine hydrochloride is 5:180:0.35, carbon black is added to 0.05M Tris-HCl buffer solution (pH=8.5), and ultrasonic dispersion is carried out for 30min (ultrasonic power is 100W, ultrasonic frequency is 40kHz), then dopamine hydrochloride is added, then stirring reaction is carried out at 400rpm in water bath at 50℃ for 30min, after reaction, centrifugation is carried out at 3500rpm for 8min, washing is carried out with deionized water for 3 times (each time deionized water is 20% of the mass of Tris-HCl buffer solution), and finally vacuum drying is carried out at 55℃ for 12h, to obtain polydopamine coated carbon black;

[0067] S2: According to the mass ratio of pretreated composite gel agent to suspension is 1.2:10, the pretreated composite gel agent is added to the suspension in step S1, and after stirring uniformly, the ceramic slurry is obtained;

[0068] The specific steps of the pretreated composite gel agent are as follows:

[0069] The composite gel agent is added to 0.01M sodium hydroxide solution (the mass of the composite gel agent is 8% of the mass of the sodium hydroxide solution), and the pH value of the system is adjusted to 9.5, then heated to 70℃, stirred until completely dissolved, then cooled to 35℃, to obtain the pretreated composite gel agent, wherein the composite gel agent is composed of poly(isobutylene-alt-maleic anhydride) and gelatin with a mass ratio of 0.75:0.45;

[0070] S3: After coating dimethyl silicone oil (the mass of the dimethyl silicone oil is 0.25% of the mass of the ceramic slurry) on the inner wall of the mold (SUS304 stainless steel mold), the ceramic slurry in step S2 is injected into the mold (SUS304 stainless steel mold), and the ceramic slurry is placed and formed, after demolding and drying, the temperature of the demolding and drying is 55℃, and the time is 26h, to obtain the green body, after reaction sintering, the process of reaction sintering is as follows: the green body is put into a high-temperature sintering furnace for silicon infiltration reaction sintering, the mass ratio of the green body and silicon is controlled to be 1:0.7, the temperature is raised to 1550℃ at a temperature rising rate of 15℃ / min, and the temperature is kept for 4h, then fine grinding and polishing are carried out, to obtain the high-precision silicon carbide combined guide rail.

[0071] Example 3

[0072] A high-precision silicon carbide combined guide rail preparation method, comprising the following steps:

[0073] S1: according to the mass ratio of modified reinforced silicon carbide powder, compounded dispersant and deionized water is 1.1:0.015:0.4, the modified reinforced silicon carbide powder, compounded dispersant and deionized water are mixed, then ball milling, using zirconia ball as grinding ball, control the mass ratio of zirconia ball and modified reinforced silicon carbide powder is 4:1 (i.e. ball to material ratio is 4:1), ball milling speed is 300r / min, ball milling time is 6h, after ball milling, get the suspension, wherein, the compounded dispersant is composed of tetramethylammonium hydroxide and sodium polyacrylate according to the mass ratio of 1:3;

[0074] The preparation method of the modified reinforced silicon carbide powder comprises the following steps:

[0075] According to the mass ratio of reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyl trimethoxysilane, ethanol and deionized water mixed solution is 10.2:0.3:60, the reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyl trimethoxysilane, ethanol and deionized water mixed solution (the volume ratio of ethanol and deionized water is 5:1) are uniformly mixed, then stirred at 600rpm in 70℃ water bath for 4h, after reaction, centrifuged at 4000rpm for 5min, washed with deionized water for 3 times (each time deionized water mass is 30% of the mass of ethanol and deionized water mixed solution), finally vacuum dried at 65℃ for 12h, get the modified reinforced silicon carbide powder, wherein, the reinforced silicon carbide powder is composed of hydroxylated silicon carbide powder and polydopamine coated carbon black according to the mass ratio of 1.1:0.4;

[0076] The preparation method of the polydopamine coated carbon black comprises the following steps:

[0077] According to the mass ratio of carbon black, Tris-HCl buffer solution and dopamine hydrochloride is 5.2:190:0.4, carbon black is added into 0.05M Tris-HCl buffer solution (pH=8.5), and ultrasonic dispersion for 35min (ultrasonic power is 100W, ultrasonic frequency is 40kHz), then add dopamine hydrochloride, then stirred at 500rpm in 55℃ water bath for 25min, after reaction, centrifuged at 4000rpm for 5min, washed with deionized water for 3 times (each time deionized water mass is 20% of the mass of Tris-HCl buffer solution), finally vacuum dried at 60℃ for 12h, get the polydopamine coated carbon black;

[0078] S2: according to the mass ratio of pretreated composite gel agent and suspension is 1.5:10, the pretreated composite gel agent is added into the suspension in step S1, after stirring uniformly, get the ceramic slurry;

[0079] The specific steps of the pretreated composite gel agent are:

[0080] The composite gel is added into 0.01M sodium hydroxide solution (the mass of the composite gel is 10% of the mass of the sodium hydroxide solution), and the pH value of the system is adjusted to 10, then heated to 75℃, stirred until completely dissolved, then cooled to 40℃, to obtain a pretreated composite gel, wherein the composite gel is composed of poly(isobutylene-alt-maleic anhydride) and gelatin in a mass ratio of 0.8:0.5;

[0081] S3: After coating dimethyl silicone oil (the mass of the dimethyl silicone oil is 0.3% of the mass of the ceramic slurry) on the inner wall of a mold (SUS304 stainless steel mold), the ceramic slurry in step S2 is injected into the mold (SUS304 stainless steel mold), and the ceramic slurry is left to form, and after demolding and drying, the temperature for demolding and drying is 60℃, and the time is 24h, to obtain a green body, which is subjected to reaction sintering, and the process of reaction sintering is as follows: the green body is placed in a high-temperature sintering furnace, and siliconizing reaction sintering is performed, the mass ratio of the green body and silicon metal is controlled to be 1:0.8, the temperature is raised to 1600℃ at a temperature rising rate of 20℃ / min, and the temperature is kept for 3h, and then fine grinding and polishing are performed, to obtain a high-precision silicon carbide combined guide rail.

[0082] Comparative Example 1

[0083] The difference between this comparative example and Example 3 is that, in the preparation of the high-precision silicon carbide combined guide rail, in step S1, the equal mass of the complex dispersant is replaced by tetramethylammonium hydroxide, and the remaining steps and raw materials are implemented synchronously with Example 3.

[0084] S1: The modified reinforced silicon carbide powder, tetramethylammonium hydroxide and deionized water are mixed according to a mass ratio of 1.1:0.015:0.4, and then ball milling is performed, zirconia balls are used as grinding balls, the mass ratio of the zirconia balls and the modified reinforced silicon carbide powder is controlled to be 4:1 (i.e. the ball-to-material ratio is 4:1), the ball milling speed is 300r / min, and the ball milling time is 6h, after the ball milling is completed, a suspension is obtained.

[0085] Comparative Example 2

[0086] The difference between this comparative example and Example 3 is that, in the preparation of the high-precision silicon carbide combined guide rail, in step S1, the equal mass of the complex dispersant is replaced by sodium polyacrylate, and the remaining steps and raw materials are implemented synchronously with Example 3.

[0087] S1: according to the mass ratio of modified reinforced silicon carbide powder, sodium polyacrylate and deionized water is 1.1:0.015:0.4, the modified reinforced silicon carbide powder, sodium polyacrylate and deionized water are mixed, and then ball milling is carried out, zirconia balls are used as grinding balls, the mass ratio of zirconia balls to modified reinforced silicon carbide powder is controlled to be 4:1 (i.e. the ball-to-material ratio is 4:1), the ball milling speed is 300 r / min, the ball milling time is 6 h, and after the ball milling is completed, the suspension is obtained.

[0088] Comparative Example 3

[0089] The difference between the present comparative example and Example 3 is that in the preparation of the high-precision silicon carbide combined guide rail, in step S1, the reinforced silicon carbide powder is composed of hydroxylated silicon carbide powder and carbon black, and the remaining steps and raw materials are the same as in Example 3.

[0090] The preparation method of the modified reinforced silicon carbide powder comprises the following steps:

[0091] According to the mass ratio of the reinforced silicon carbide powder, N-aminoethyl-γ-aminopropyl trimethoxysilane, ethanol and deionized water mixed solution is 10.2:0.3:60, the silicon carbide powder, N-aminoethyl-γ-aminopropyl trimethoxysilane, ethanol and deionized water mixed solution (the volume ratio of ethanol and deionized water is 5:1) are mixed uniformly, then stirred at 600 rpm in a water bath at 70°C for 4 h, after the reaction, centrifuged at 4000 rpm for 5 min, washed with deionized water for 3 times (each time the mass of deionized water is 30% of the mass of the ethanol and deionized water mixed solution), and finally vacuum dried at 65°C for 12 h, to obtain the modified reinforced silicon carbide powder, wherein the reinforced silicon carbide powder is composed of hydroxylated silicon carbide powder and carbon black with a mass ratio of 1.1:0.4.

[0092] Comparative Example 4

[0093] The difference between the present comparative example and Example 3 is that in the preparation of the high-precision silicon carbide combined guide rail, in step S1, the reinforced silicon carbide powder is replaced by hydroxylated silicon carbide powder with the same mass, and the remaining steps and raw materials are the same as in Example 3.

[0094] The preparation method of the modified reinforced silicon carbide powder comprises the following steps:

[0095] According to the mass ratio of the hydroxylated silicon carbide powder, N-aminoethyl-γ-aminopropyl trimethoxysilane, ethanol and deionized water mixed solution is 10.2:0.3:60, the hydroxylated silicon carbide powder, N-aminoethyl-γ-aminopropyl trimethoxysilane, ethanol and deionized water mixed solution (the volume ratio of ethanol and deionized water is 5:1) is uniformly mixed, then stirred at 600 rpm in a water bath at 70°C for 4h, after the reaction is completed, centrifuged at 4000 rpm for 5 min, washed with deionized water for 3 times (each time the mass of deionized water is 30% of the mass of the ethanol and deionized water mixed solution), and finally vacuum dried at 65°C for 12h to obtain the modified reinforced silicon carbide powder.

[0096] Comparative Example 5

[0097] The difference between this comparative example and Example 3 is that in the preparation of the high-precision silicon carbide combined guide rail, the composite gel agent in step S2 is replaced by poly(isobutylene-alt-maleic anhydride) with the same mass, and the remaining steps and raw materials are the same as in Example 3.

[0098] S2: According to the mass ratio of the pretreated poly(isobutylene-alt-maleic anhydride) to the suspension is 1.5:10, the pretreated poly(isobutylene-alt-maleic anhydride) is added to the suspension in step S1, and after stirring uniformly, the ceramic slurry is obtained.

[0099] The specific steps of the pretreated composite gel agent are as follows:

[0100] The poly(isobutylene-alt-maleic anhydride) is added to the 0.01M sodium hydroxide solution (the mass of the poly(isobutylene-alt-maleic anhydride) is 10% of the mass of the sodium hydroxide solution), and the pH value of the system is adjusted to 10, then heated to 75°C, stirred until completely dissolved, then cooled to 40°C, and the pretreated poly(isobutylene-alt-maleic anhydride) is obtained.

[0101] Comparative Example 6

[0102] The difference between this comparative example and Example 3 is that in the preparation of the high-precision silicon carbide combined guide rail, the composite gel agent in step S2 is replaced by gelatin with the same mass, and the remaining steps and raw materials are the same as in Example 3.

[0103] S2: According to the mass ratio of the pretreated gelatin to the suspension is 1.5:10, the gelatin is added to the suspension in step S1, and after stirring uniformly, the ceramic slurry is obtained.

[0104] The specific steps of the pretreated composite gel agent are as follows:

[0105] The gelatin was added into 0.01M sodium hydroxide solution (the mass of gelatin was 10% of the mass of sodium hydroxide solution), and the pH value of the system was adjusted to 10, then heated to 75℃, stirred until completely dissolved, then cooled to 40℃, to obtain the pretreated gelatin.

[0106] The high-precision silicon carbide combined guide rails prepared in Examples 1-3 and Comparative Examples 1-6 were tested for volume density, density, bending strength and thermal conductivity. The density test was performed according to the standard GB / T 25995-2010; the density test was performed by a density analyzer; the bending strength test was performed according to the standard GB / T 6569-2006; and the thermal conductivity test was performed according to the standard GB / T 22588-2008. The test results are shown in Table 1 below:

[0107] Table 1 Performance parameters of high-precision silicon carbide combined guide rails

[0108]

[0109] From the data in Table 1 above, it can be seen that, by comparing Comparative Examples 1-4 and Example 3, it is found that, when the compound dispersant is replaced by tetramethylammonium hydroxide or sodium polyacrylate in equal mass, or when the reinforcing silicon carbide powder is composed of hydroxylated silicon carbide powder and carbon black, or when the reinforcing silicon carbide powder is replaced by hydroxylated silicon carbide powder in equal mass, the test results of the finally prepared high-precision silicon carbide combined guide rails are poorer than those of Example 3, indicating that the compound dispersant composed of tetramethylammonium hydroxide and sodium polyacrylate has a synergistic effect, which not only can better improve the dispersibility and stability of the modified reinforcing silicon carbide powder, but also can further improve the mechanical properties and density of the combined 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 properties and thermal conductivity of the silicon carbide combined guide rail, and increase its density;

[0110] From the comparison between Comparative Examples 5-6 and Example 3, it can be seen that, when the compound gel agent is replaced by poly(isobutylene-alt-maleic anhydride) or gelatin in equal mass, the test results of the finally prepared high-precision silicon carbide combined guide rails are poorer than those of Example 3, indicating that the compound gel agent composed of poly(isobutylene-alt-maleic anhydride) and gelatin can have a synergistic effect, which can convert the ceramic slurry into a three-dimensional cross-linked network, improve the mechanical strength and dimensional accuracy of the green body, further improve the mechanical properties and dimensional stability of the combined guide rail, and increase its density.

[0111] From the above table 1, the high-precision silicon carbide combined guide rail prepared by examples 1-3, compared with the high-precision silicon carbide combined guide rail prepared by comparative examples 1-6, by mixing modified reinforced silicon carbide powder, compound dispersing agent and deionized water, ball milling to obtain suspension, adding pretreated composite gel agent into the suspension, stirring uniformly to obtain ceramic slurry, coating release agent in the mold, injecting ceramic slurry, standing forming, demolding and drying to obtain green body, after reaction sintering, fine grinding and polishing processing, finally obtaining high-precision silicon carbide combined guide rail, meeting the requirements of test performance, while the high-precision silicon carbide combined guide rail prepared by comparative examples 1-6 does not meet the performance requirements, which shows that the high-precision silicon carbide combined guide rail prepared by the application has high mechanical strength, purity, density, thermal stability and dimensional stability, and good overall comprehensive performance.

[0112] In the description of the specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0113] The above is only an example and description of the application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace, as long as it does not deviate from the application or exceed the scope defined by the application, which shall belong to the protection scope of the application.

Claims

1. A method for manufacturing a high-precision silicon carbide composite guide rail, characterized by, The method comprises the following steps: S1: mixing modified reinforced silicon carbide powder, compound dispersant and deionized water, then ball milling to obtain a suspension; S2: adding pretreated composite gel to the suspension in step S1, stirring uniformly to obtain a ceramic slurry; S3: coating a release agent on the inner side wall of a mold, injecting the ceramic slurry in step S2 into the mold, standing for forming, demolding and drying to obtain a green body, then performing reaction sintering, fine grinding and polishing to obtain a high-precision silicon carbide combined guide rail; The compound dispersant is composed of tetramethylammonium hydroxide and sodium polyacrylate with a mass ratio of 1:2-3; The preparation method of the modified reinforced silicon carbide powder comprises the following steps: Mixing a mixed solution of reinforced silicon carbide powder, silane coupling agent, ethanol and deionized water uniformly, then stirring and reacting in a water bath, after the reaction, centrifuging, washing with deionized water, and finally vacuum drying to obtain the modified reinforced silicon carbide powder; The silane coupling agent is N-aminoethyl-gamma-aminopropyltrimethoxysilane; The reinforced silicon carbide powder is composed of hydroxylated silicon carbide powder and polydopamine-coated carbon black with a mass ratio of 0.9-1.1:0.3-0.4; The composite gel is composed of poly(isobutylene-alt-maleic anhydride) and gelatin with a mass ratio of 0.7-0.8:0.4-0.

5.

2. The method of claim 1, wherein the high-precision SiC composite guide rail is prepared by the steps of: In step S1, the mass ratio of the modified 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 of claim 1, wherein the high-precision SiC composite guide rail is prepared by the steps of: The preparation method of the polydopamine-coated carbon black comprises the following steps: ​ Adding carbon black into a Tris-HCl buffer solution and ultrasonic dispersing, then adding hydrochloric acid dopamine, stirring and reacting in a water bath, after the reaction, centrifuging, washing with deionized water, and finally vacuum drying to obtain the polydopamine-coated carbon black.

4. 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 of the pretreated composite gel are as follows: Adding the composite gel into a sodium hydroxide solution, adjusting the pH value of the system to 9-10, then heating to 65-75℃, stirring until completely dissolved, then cooling to 30-40℃ to obtain the pretreated composite gel.

5. The method of claim 1, wherein the high-precision SiC composite guide rail is prepared by the steps of: In step S3, the process of reaction sintering is as follows: placing the green body into a high-temperature sintering furnace, performing silicon infiltration reaction sintering, controlling the mass ratio of the green body and metallic silicon to be 1:0.6-0.8, heating to 1500-1600℃ at a heating rate of 10-20℃ / min, and keeping the temperature for 3-5h. ​

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