Titanium silicon carbide enhanced reaction sintered silicon carbide ceramic and preparation method thereof

Abstract

The present invention discloses a titanium silicon carbide enhanced reaction sintered silicon carbide ceramic and a preparation method thereof, the method comprising: using 35-55% silicon carbide powder, 30-45% carbon black and 10-20% titanium dioxide powder as main raw materials, mixing with a binder, a dispersant and water to prepare a ceramic slurry; placing the ceramic slurry in a mold, drying and demolding after standing to obtain a porous ceramic body; burying the porous ceramic body with silicon powder, heating to 1300-1400°C in a flowing inert atmosphere, and keeping the temperature; then heating to 1650-1750°C, maintaining a vacuum degree of 1-30Pa, and keeping the temperature to obtain the ceramic material. The present invention obtains Ti by a one-step method combining carbon thermal reduction and reaction infiltration. 3 SiC 2 Enhanced reaction-sintered silicon carbide ceramics by in-situ generation of Ti 3 SiC 2 This reduces the residual Si content in the ceramics, achieves reinforcement and toughening of the reaction-sintered silicon carbide ceramics, and improves the preparation efficiency.

Description

Technical Field

[0001] The invention relates to titanium silicon carbide reinforced reaction sintered silicon carbide ceramic and a preparation method thereof, belonging to the technical field of reaction sintered silicon carbide ceramic preparation. Background Art

[0002] Silicon carbide ceramics (SiC ceramics) not only have good mechanical properties such as high hardness, high stiffness, and wear resistance, but also have excellent thermal properties such as oxidation resistance, thermal shock resistance, high thermal conductivity, and low thermal expansion coefficient, which makes it applicable to precision bearings, compression cylinders, wear-resistant seals, gas rotors, nozzle nuclear reactors, and thermonuclear reactors. At present, the mainstream processes for preparing silicon carbide ceramics are pressureless sintering, hot pressing sintering, hot isostatic pressing sintering, and reaction sintering. Among them, the general process of the reaction sintering method is: mixing silicon carbide powder, carbon powder and binder, sintering, drying, debinding, and finally siliconizing to obtain ceramic products; it usually has the advantages of simple preparation process, low sintering temperature, short sintering time, and can achieve net size sintering. The reaction sintered silicon carbide ceramic material has broad application prospects in high-tech fields such as aerospace, high-temperature structural parts, and wear-resistant components.

[0003] Although reaction-sintered silicon carbide ceramics have many advantages, they are currently rarely used in the field of load-bearing components. This is mainly due to the residual silicon in the ceramic material, which easily amplifies the defects of excessive brittleness and low toughness of the ceramic, resulting in reduced mechanical properties of the sintered body. In addition, the melting point of free silicon is 1410°C, which also limits the use of reaction-sintered silicon carbide in high-temperature environments. With the widespread application of reaction-sintered silicon carbide as a high-tech ceramic, it is particularly important to reduce the residual silicon content in reaction-sintered silicon carbide by optimizing the preparation process, introducing toughening materials, etc., and improving the mechanical properties and reliability of reaction-sintered silicon carbide-based composites. Summary of the invention

[0004] In order to overcome the defects of the prior art, the purpose of the present invention is to provide a titanium silicon carbide enhanced reaction sintered silicon carbide ceramic and a preparation method thereof. Through the preparation process technology of the present invention, the residual silicon content in the reaction sintered silicon carbide ceramic can be reduced, and the enhancement and toughening of the ceramic material can be effectively achieved.

[0005] The present invention provides a method for preparing titanium silicon carbide enhanced reaction sintered silicon carbide ceramics, comprising the following steps:

[0006] S1, using 35-55wt% of silicon carbide powder, 30-45wt% of carbon black and 10-20wt% of titanium dioxide powder as main raw materials, mixing with a binder, a dispersant and water to prepare a ceramic slurry;

[0007] S2, placing the ceramic slurry in a mold, drying and demoulding after standing, to obtain a porous ceramic body;

[0008] S3. The porous ceramic body is buried with silicon powder, heated to 1300-1400°C in a flowing inert atmosphere, kept warm, and subjected to carbon thermal reduction to obtain a SiC / TiC / C porous ceramic preform; then heated to 1650-1750°C, maintained at a vacuum degree of 1-30 Pa, kept warm, and then cooled to obtain Ti3SiC2 enhanced reaction sintered silicon carbide ceramics.

[0009] Preferably, in step S1, the purity of the silicon carbide powder is 85-99.9% and the particle size is 5-40 μm.

[0010] Preferably, in step S1, the purity of the titanium dioxide powder is 90-99.9% and the particle size is 1-10 μm.

[0011] Preferably, in step S1, the purity of the carbon black is 95-99.9% and the particle size is 1-20 μm.

[0012] Preferably, in step S1, the binder is sodium hydroxymethyl cellulose and / or hydroxyethyl cellulose; the amount of the binder is 1 to 5 wt % of the total weight of the main raw material.

[0013] Preferably, in step S1, the dispersant is one or more of ethanol, methylpentanol, polyethylene glycol and fatty acid polyethylene glycol ester; the amount of the dispersant is 1 to 5 wt% of the total weight of the main raw material.

[0014] Preferably, step S1 comprises: firstly ball-milling and mixing silicon carbide powder, carbon black and titanium dioxide powder in proportion, then adding a binder and a dispersant, and then adding 80 to 100 wt % of water in terms of the total weight of the main raw materials, stirring and mixing, and obtaining a ceramic slurry.

[0015] Preferably, step S2 comprises: pouring the ceramic slurry into a mold, leaving it to stand for 7 to 9 hours, and demolding after freeze drying or blast drying to obtain a porous ceramic body.

[0016] Preferably, in step S3, the amount of silicon powder used is twice the weight of the porous ceramic blank; the insulation time under the inert atmosphere is 2 to 10 hours, and the vacuum insulation time is 30 to 120 minutes, followed by natural cooling to obtain Ti3SiC2 enhanced reaction sintered silicon carbide ceramics.

[0017] The present invention provides a Ti3SiC2 enhanced reaction sintered silicon carbide ceramic prepared by the preparation method as described above.

[0018] Compared with the prior art, the present invention provides a technology for preparing reaction-sintered silicon carbide ceramic materials with a simple process and easy-to-control process. The present invention uses a one-step method combining carbon thermal reduction with reaction infiltration, mainly using excess carbon black to ensure the complete reaction of titanium dioxide to generate TiC, and as a carbon source for reaction infiltration, and the residual Si in the reaction-sintered silicon carbide ceramics at high temperature can also react with TiC to generate a high-strength phase Ti3SiC2, thereby obtaining Ti3SiC2-reinforced reaction-sintered silicon carbide ceramics. The present invention reduces the residual Si content in the ceramics through the in-situ generated Ti3SiC2, achieves the enhancement and toughening of the reaction-sintered silicon carbide ceramics, simplifies the process, improves the preparation efficiency of the ceramic material, and is suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention or the core of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings under the premise of continuous creative work.

[0020] Figure 1 The XRD pattern of TiC / C composite porous ceramics prepared by carbothermal reduction is explored before the implementation of the present invention;

[0021] Figure 2 This is an SEM image of TiC / C composite porous ceramics prepared by carbothermal reduction before the implementation of the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. Unless otherwise defined, all professional terms used hereinafter have the same meaning as those skilled in the art generally understand. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0023] In order to solve the above technical problems, the present invention provides a method for preparing titanium silicon carbide enhanced reaction sintered silicon carbide ceramics, comprising the following steps:

[0024] 35-55wt% of silicon carbide powder, 30-45wt% of carbon black and 10-20wt% of titanium dioxide powder are used as main raw materials, mixed with a binder, a dispersant and water to prepare a ceramic slurry;

[0025] S2, placing the ceramic slurry in a mold, drying and demoulding after standing, to obtain a porous ceramic body;

[0026] S3. The porous ceramic body is buried with silicon powder, heated to 1300-1400°C in a flowing inert atmosphere, kept warm, and subjected to carbon thermal reduction to obtain a SiC / TiC / C porous ceramic preform; then heated to 1650-1750°C, maintained at a vacuum degree of 1-30 Pa, kept warm, and then cooled to obtain Ti3SiC2 enhanced reaction sintered silicon carbide ceramics.

[0027] The method for preparing reaction-sintered silicon carbide ceramic material provided by the present invention can reduce the residual Si content in the reaction-sintered silicon carbide ceramic, effectively realize the strengthening and toughening of the ceramic material, and the preparation method is simple in process and easy to control.

[0028] The technical solution adopted in the embodiment of the present invention is as follows:

[0029] The main raw materials in the embodiment of the present invention include: 35-55wt% silicon carbide powder, 30-45wt% carbon black and 10-20wt% titanium dioxide powder. Among them, the weight proportion of the silicon carbide powder is preferably 45-55wt%, and its powder purity can be 85-99.9%, and further more than 90%. The silicon carbide powder can be a conventional SiC powder available on the market, and its particle size is specifically 5-40μm, such as 5μm, 10μm, 20μm, 25μm, 40μm. The weight proportion of the carbon black is 30-45wt%, which is relatively excessive. In some embodiments, the purity of the carbon black is 95-99.9%, and the particle size is 1-20μm, specifically 1μm, 5μm, 10μm, 15μm, 20μm.

[0030] In addition, the embodiment of the present invention uses 10-20wt% titanium dioxide powder, preferably 15-20wt%, so that the subsequent reaction forms a reinforced and toughened silicon carbide ceramic composite material. The purity of the titanium dioxide powder can be 90-99.9%, and the particle size is preferably 1-10μm, more preferably 1-7μm, specifically 1μm, 2μm, 3μm, 4μm, 5μm.

[0031] According to the preferred embodiment of the present invention, SiC powder, titanium dioxide powder and carbon black can be ball-milled for 1-3 hours according to the above-mentioned weight ratio to make them fully mixed; the main raw materials after ball milling are placed in a stirring tank, and further 1-5wt% of the total weight of the main raw materials The binder and 1-5wt% of the total weight of the main raw materials are added. The dispersant is then added with 80% to 100% of the total weight of the main raw materials. Water (deionized water is generally used in the laboratory) is added, and stirring is continued for 30 to 60 minutes to obtain a ceramic slurry.

[0032] Wherein, the binder is mainly a cellulose binder, preferably one or more of sodium hydroxymethyl cellulose and hydroxyethyl cellulose.

[0033] Preferably, the dispersant is one or more of ethanol, methylpentanol, polyethylene glycol and fatty acid polyethylene glycol ester, and further ethanol, methylpentanol or polyethylene glycol, which can improve the wetting and suspension of powder particles. The polymers in the dispersant are all commonly used additives in the art, and there is no special restriction on their molecular weight.

[0034] In the embodiment of the present invention, the ceramic slurry obtained in the above steps is poured into a mold, preferably left to stand for 7 to 9 hours, and can be freeze-dried or forced-dried for at least 24 hours, and then demolded to obtain a porous ceramic body. After obtaining the porous ceramic body, in the embodiment of the present invention, silicon powder of the same weight as the porous ceramic body can be weighed, poured into a graphite crucible and spread, the porous ceramic body can be placed on the spread silicon powder, and then the same weight of silicon powder can be weighed and spread on the porous ceramic body, so that the porous ceramic body is buried in the silicon powder. The purity and particle size of the silicon powder are conventional and there are no special restrictions. Specifically, the embodiment of the present invention places the above-mentioned graphite crucible into a vacuum carbon tube furnace, raises the temperature to 1300-1400°C (the reaction temperature of carbon thermal reduction here can be 1300°C, 1350°C, 1400°C, etc.) under an inert atmosphere such as flowing argon, and keeps it warm for 2-10 hours, such as 3 hours, 4 hours, 5 hours, 6 hours, and 8 hours, to obtain a SiC / TiC / C porous ceramic preform through carbon thermal reduction.

[0035] After the insulation of the embodiment of the present invention is completed, the temperature is raised to 1650-1750°C, and the vacuum degree in the carbon tube furnace is maintained at 1-30Pa, preferably for 30-120min. After the insulation is completed, it can be cooled naturally to obtain Ti3SiC2 enhanced reaction sintered silicon carbide ceramics. Among them, the temperature of the vacuum reaction infiltration of the embodiment of the present invention can be 1650°C, 1700°C, 1750°C, etc. In the embodiment of the present invention, TiC is first generated in situ in the porous ceramic body by carbon thermal reduction of titanium dioxide powder and carbon black, and then the molten Si and carbon black are reacted to generate SiC by reaction infiltration, and the residual Si in the reaction sintered silicon carbide ceramic at high temperature can contact and react with TiC to generate high-strength Ti3SiC2, thereby achieving the enhancement of the reaction sintered silicon carbide ceramic material. The embodiment of the present invention mainly adopts a one-step method of carbon thermal reduction combined with reaction infiltration to obtain Ti3SiC2 enhanced reaction sintered silicon carbide ceramics, which has a simple process and is easy to control. No secondary treatment is required after one-step synthesis, and the preparation efficiency is high.

[0036] Accordingly, the present invention provides a Ti3SiC2 enhanced reaction-sintered silicon carbide ceramic prepared by the preparation method as described above.

[0037] In some embodiments, the bending strength of the Ti3SiC2 enhanced reaction-sintered silicon carbide ceramic is 356-410 MPa, and the fracture toughness can reach 5.5 MPa·m 1 / 2The Ti3SiC2 reinforced reaction-sintered silicon carbide ceramics described in the embodiment of the present invention have a Ti3SiC2 reinforcement phase, which reduces the residual carbon content in the reaction-sintered silicon carbide ceramics and introduces a second phase to achieve reinforcement, thereby improving the strength and toughness of the ceramics; at the same time, it is prepared by a one-step method, which is easy to operate and has the advantages of reducing costs and increasing efficiency.

[0038] In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples. Unless otherwise specified, the various reagents and raw materials used in the present invention are all commodities that can be purchased from the market or products that can be prepared by recognized methods.

[0039] Example 1

[0040] In each of the following examples, the steps of the method for preparing Ti3SiC2 enhanced reaction sintered silicon carbide ceramics include:

[0041] Step 1: Using 55wt% of silicon carbide powder, 30wt% of carbon black and 15wt% of titanium dioxide powder as main raw materials, ball-milling the silicon carbide powder, titanium dioxide powder and carbon black for 3h to fully mix them, placing the ball-milled main raw materials in a stirring tank, adding 5wt% of the total weight of the main raw materials, a binder and a dispersant of 5wt% of the total weight of the main raw materials, and then adding 100% of the total weight of the main raw materials, deionized water, and stirring for 30min to obtain a ceramic slurry;

[0042] Step 2: pour the ceramic slurry into a mold, let it stand for 8 hours, and then air dry it for 24 hours before demolding to obtain a porous ceramic body.

[0043] Step 3, weighing silicon powder of the same weight as the porous ceramic body, pouring it into a graphite crucible and spreading it, placing the porous ceramic body on the spread silicon powder, and then weighing the same weight of silicon powder and spreading it on the porous ceramic body, so that the porous ceramic body is buried in the silicon powder; placing the crucible in a vacuum carbon tube furnace, heating it to 1300° C. under a flowing argon atmosphere, keeping it warm for 5 hours, and obtaining a SiC / TiC / C porous ceramic preform by carbon thermal reduction;

[0044] Step 4: After the heat preservation is completed, the temperature is raised to 1650°C, the vacuum degree in the carbon tube furnace is maintained at 30Pa, and the heat preservation is carried out for 120 minutes. After the heat preservation is completed, it is naturally cooled to obtain Ti3SiC2 enhanced reaction sintered silicon carbide ceramics.

[0045] The purity of the silicon carbide powder is 95% and the particle size is 5 μm; the purity of the titanium dioxide powder is 99% and the particle size is 5 μm; the purity of the carbon black is 98% and the particle size is 15 μm. The binder is sodium hydroxymethyl cellulose and the dispersant is polyethylene glycol.

[0046] According to the national standard test method, the bending strength of the Ti3SiC2 reinforced reaction sintered silicon carbide ceramics is 396MPa and the fracture toughness is 5.3MPa·m 1 / 2 .

[0047] Example 2

[0048] Same as Example 1, except that the carbon thermal reduction temperature is 1400°C.

[0049] The bending strength of the Ti3SiC2 reinforced reaction sintered silicon carbide ceramics is 418MPa and the fracture toughness is 5.5MPa·m 1 / 2 .

[0050] Example 3

[0051] Same as Example 1, except that the vacuum reaction infiltration temperature is 1700°C.

[0052] The bending strength of the Ti3SiC2 reinforced reaction sintered silicon carbide ceramics is 406MPa and the fracture toughness is 5.1MPa·m 1 / 2 .

[0053] Example 4

[0054] Step 1: Using 50wt% of silicon carbide powder, 35wt% of carbon black and 15wt% of titanium dioxide powder as main raw materials, ball-milling the silicon carbide powder, titanium dioxide powder and carbon black for 3h to fully mix them, placing the ball-milled raw materials in a stirring tank, adding 3wt% of a binder and 3wt% of a dispersant based on the total weight of the main raw materials, and then adding 80% of deionized water based on the total weight of the main raw materials, stirring continuously for 60min to obtain a ceramic slurry;

[0055] Step 2: pour the ceramic slurry into a mold, let it stand for 8 hours, and then air dry it for 24 hours before demoulding to obtain a porous ceramic body;

[0056] Step 3, weighing silicon powder of the same weight as the porous ceramic body, pouring it into a graphite crucible and spreading it, placing the porous ceramic body on the spread silicon powder, and then weighing the same weight of silicon powder and spreading it on the porous ceramic body, so that the porous ceramic body is buried in the silicon powder; placing the crucible in a vacuum carbon tube furnace, heating it to 1350° C. under a flowing argon atmosphere, keeping it warm for 3 hours, and obtaining a SiC / TiC / C porous ceramic preform by carbon thermal reduction;

[0057] Step 4: After the heat preservation is completed, the temperature is raised to 1750°C, the vacuum degree in the carbon tube furnace is maintained at 30Pa, and the heat preservation is carried out for 30 minutes. After the heat preservation is completed, it is naturally cooled to obtain Ti3SiC2 enhanced reaction sintered silicon carbide ceramics.

[0058] The purity of the silicon carbide powder is 99% and the particle size is 40 μm; the purity of the titanium dioxide powder is 96% and the particle size is 3 μm; the purity of the carbon black is 99% and the particle size is 20 μm. The binder is hydroxyethyl cellulose and the dispersant is methyl amyl alcohol.

[0059] The bending strength of the Ti3SiC2 reinforced reaction-sintered silicon carbide ceramics is 387MPa and the fracture toughness is 4.5MPa·m 1 / 2 .

[0060] Example 5

[0061] Same as Example 4, except that the carbon thermal reduction temperature is 1400°C.

[0062] The bending strength of the Ti3SiC2 reinforced reaction-sintered silicon carbide ceramics is 408MPa and the fracture toughness is 5.2MPa·m 1 / 2 .

[0063] Example 6

[0064] Same as Example 4, the only difference is that the vacuum reaction infiltration temperature is 1700°C.

[0065] The bending strength of the Ti3SiC2 reinforced reaction-sintered silicon carbide ceramics is 392MPa and the fracture toughness is 5.1MPa·m 1 / 2 .

[0066] Example 7

[0067] Step 1: Using 45wt% of silicon carbide powder, 45wt% of carbon black and 10wt% of titanium dioxide powder as main raw materials, ball-milling the silicon carbide powder, titanium dioxide powder and carbon black for 3h to fully mix them, placing the ball-milled raw materials in a stirring tank, adding 1wt% of a binder and 5wt% of a dispersant based on the total weight of the main raw materials, and then adding 90% of deionized water based on the total weight of the main raw materials, stirring continuously for 30min to obtain a ceramic slurry;

[0068] Step 2: pour the ceramic slurry into a mold, let it stand for 8 hours, and then air dry it for 24 hours before demoulding to obtain a porous ceramic body;

[0069] Step 3, weighing silicon powder of the same weight as the porous ceramic body, pouring it into a graphite crucible and spreading it, placing the porous ceramic body on the spread silicon powder, and then weighing the same weight of silicon powder and spreading it on the porous ceramic body, so that the porous ceramic body is buried in the silicon powder; placing the crucible in a vacuum carbon tube furnace, heating it to 1300° C. under a flowing argon atmosphere, keeping it warm for 6 hours, and obtaining a SiC / TiC / C porous ceramic preform by carbon thermal reduction;

[0070] Step 4: After the insulation is completed, the temperature is raised to 1700°C, the vacuum degree in the carbon tube furnace is maintained at 10Pa, and the temperature is maintained for 120 minutes. After the insulation is completed, it is naturally cooled to obtain Ti3SiC2 enhanced reaction sintered silicon carbide ceramics.

[0071] The purity of the silicon carbide powder is 97% and the particle size is 20 μm; the purity of the titanium dioxide powder is 98% and the particle size is 4 μm; the purity of the carbon black is 99% and the particle size is 10 μm. The binder is hydroxyethyl cellulose and the dispersant is ethanol.

[0072] The bending strength of the Ti3SiC2 reinforced reaction sintered silicon carbide ceramics is 375MPa and the fracture toughness is 4.8MPa·m 1 / 2 .

[0073] Example 8

[0074] Same as Example 7, except that the carbon thermal reduction holding time is 3 h.

[0075] The bending strength of the Ti3SiC2 reinforced reaction-sintered silicon carbide ceramics is 356MPa and the fracture toughness is 4.4MPa·m 1 / 2 .

[0076] Example 9

[0077] Same as Example 7, except that the vacuum reaction infiltration temperature is 1750°C.

[0078] The bending strength of the Ti3SiC2 reinforced reaction-sintered silicon carbide ceramics is 383MPa and the fracture toughness is 5.0MPa·m 1 / 2 .

[0079] Figure 1 Before the implementation of the present invention, the XRD (X-ray diffraction) diagram of TiC / C composite porous ceramics prepared by carbon thermal reduction at 1400°C was explored. Analysis showed that titanium dioxide was converted into TiC and a small amount of C remained, which can be used as a carbon source for vacuum reactive infiltration. Figure 2 The SEM (scanning electron microscope) image of the TiC / C composite porous ceramic prepared by carbon thermal reduction was explored before the implementation of the present invention. Analysis showed that the TiC / C grains and pores in the porous ceramics prepared by the preparation process of the present invention are evenly distributed, which is beneficial to the contact and reaction of the silicon source infiltration with C and TiC in the subsequent vacuum reactive infiltration, and is beneficial to the preparation of Ti3SiC2 enhanced reaction sintered silicon carbide ceramics.

[0080] As can be seen from the above embodiments, the process of the present invention is simple and the process is easy to control. TiC can be generated in situ in a porous ceramic body by carbon thermal reduction of titanium dioxide powder and carbon black, and then molten Si and carbon black are reacted by reactive infiltration to generate SiC, etc., to achieve reactive sintering of ceramic materials. The present invention obtains Ti3SiC2-enhanced reactive sintered silicon carbide ceramics in one step, improves the preparation efficiency of the material, and reduces the residual Si content in the ceramic by in situ generation of Ti3SiC2, thereby achieving reinforcement and toughening of reactive sintered silicon carbide ceramics.

[0081] It should be noted that, for those skilled in the art, several improvements and modifications may be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for preparing titanium silicon carbide enhanced reaction sintered silicon carbide ceramics, characterized in that: The following steps are involved: S1, using 35-55wt% of silicon carbide powder, 30-45wt% of carbon black and 10-20wt% of titanium dioxide powder as main raw materials, mixing with a binder, a dispersant and water to prepare a ceramic slurry; S2, placing the ceramic slurry in a mold, drying and demoulding after standing, to obtain a porous ceramic body; S3. The porous ceramic body is buried with silicon powder, heated to 1300-1400°C in a flowing inert atmosphere, kept warm, and subjected to carbon thermal reduction to obtain a SiC / TiC / C porous ceramic preform; then heated to 1650-1750°C, maintained at a vacuum degree of 1-30 Pa, kept warm, and then cooled to obtain Ti3SiC2 enhanced reaction sintered silicon carbide ceramics.

2. The method for preparing titanium silicon carbide enhanced reaction-sintered silicon carbide ceramics according to claim 1, characterized in that: In step S1, the purity of the silicon carbide powder is 85-99.9% and the particle size is 5-40 μm.

3. The method for preparing titanium silicon carbide enhanced reaction-sintered silicon carbide ceramics according to claim 1, characterized in that: In step S1, the purity of the titanium dioxide powder is 90-99.9% and the particle size is 1-10 μm.

4. The method for preparing titanium silicon carbide enhanced reaction-sintered silicon carbide ceramics according to claim 1, characterized in that: In step S1, the purity of the carbon black is 95-99.9% and the particle size is 1-20 μm.

5. The method for preparing titanium silicon carbide enhanced reaction-bonded silicon carbide ceramics according to claim 1, characterized in that: In step S1, the binder is sodium hydroxymethyl cellulose and / or hydroxyethyl cellulose; the amount of the binder is 1 to 5 wt % of the total weight of the main raw material.

6. The method for preparing titanium silicon carbide enhanced reaction-sintered silicon carbide ceramics according to claim 1, characterized in that: In step S1, the dispersant is one or more of ethanol, methylpentanol, polyethylene glycol and fatty acid polyethylene glycol ester; the amount of the dispersant is 1 to 5 wt% of the total weight of the main raw material.

7. The method for preparing titanium silicon carbide enhanced reaction-bonded silicon carbide ceramics according to any one of claims 1 to 6, characterized in that: Step S1 includes: firstly ball-milling and mixing silicon carbide powder, carbon black and titanium dioxide powder in proportion, then adding a binder and a dispersant, and then adding 80-100wt% of water in terms of the total weight of the main raw materials, stirring and mixing, and obtaining a ceramic slurry.

8. The method for preparing titanium silicon carbide enhanced reaction-sintered silicon carbide ceramics according to claim 7, characterized in that: Step S2 comprises: pouring the ceramic slurry into a mold, leaving it to stand for 7 to 9 hours, and demolding after freeze drying or blast drying to obtain a porous ceramic body.

9. The method for preparing titanium silicon carbide enhanced reaction-bonded silicon carbide ceramics according to claim 8, characterized in that: In step S3, the amount of silicon powder used is twice the weight of the porous ceramic blank; the insulation time under the inert atmosphere is 2 to 10 hours, and the vacuum insulation time is 30 to 120 minutes, followed by natural cooling to obtain Ti3SiC2 enhanced reaction sintered silicon carbide ceramics.

10. A Ti3SiC2 enhanced reaction-sintered silicon carbide ceramic prepared by the preparation method according to any one of claims 1 to 9.

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