A method for preparing SiC / Ti-Si-C composite material

Abstract

The present invention relates to a method for preparing a SiC / Ti-Si-C composite material. The method comprises spreading Ti-Si alloy powder onto a SiC / C porous preform, and performing in-situ reaction infiltration and sintering to obtain the SiC / Ti-Si-C composite material.

Description

Technical Field

[0001] The invention relates to a preparation method of a SiC / Ti-Si-C composite material, belonging to the field of composite materials. Background Art

[0002] Silicon carbide (SiC) ceramics are widely used in aerospace, nuclear energy, machinery, petroleum, optics, integrated circuits, semiconductors, and other fields, owing to their excellent properties, including high high-temperature strength, excellent wear resistance, excellent thermal stability, low coefficient of thermal expansion (CTE), high hardness, and superior thermal shock resistance. These ceramics are gaining increasing attention. The introduction of active elements such as Ti, Ta, Cr, Zr, and V into SiC ceramics to create SiC-based composites allows for the manipulation of chemical and mechanical properties while maintaining high electrical conductivity and oxidation resistance, making them promising composite materials. In particular, SiC ceramics have significantly contributed to the advancement of production technology and increased efficiency in the semiconductor industry.

[0003] The main methods for introducing active elements such as Ti, Ta, Cr, Zr, and V into existing SiC-based composites include powder mixing, surface coating, in-situ reaction, and prefabricated intermetallic compound introduction. Powder mixing mainly involves mixing powders of the active elements with powders of the SiC-based composite during the composite material preparation process. During the mixing process, uneven distribution or agglomeration may occur. Surface coating methods use techniques such as physical vapor deposition (PVD), chemical vapor deposition (CVD), or thermal spraying to form a coating of the active elements on the surface of SiC particles or preforms. In this method, the adhesion and consistency of the coating may be limited. In-situ reaction is the introduction of active elements in elemental form or in the form of compounds that react with SiC. At high temperatures, these active elements react with SiC to directly form new phases or compounds in the composite material. However, the temperature and time during the reaction process must be controlled to avoid uncontrolled phase changes or excessive reactions. The prefabricated intermetallic compound introduction method mainly refers to the addition of pre-prepared intermetallic compounds containing the desired active elements into SiC-based composites. In this method, the dispersion of the intermetallic compound and its reactivity with SiC need to be carefully controlled, making it impossible to apply it in batches and industrial applications. Summary of the Invention

[0004] Addressing the shortcomings of existing SiC-based composite material preparation technologies, this invention proposes a novel in-situ reactive infiltration method using SiC powder, Si particles, Ti particles, and carbon black as raw materials to achieve a single-step in-situ reaction and densification of the SiC / Ti-Si-C composite material, eliminating the need for complex processes such as high-energy ball milling and pressure sintering. This process is simple, convenient, low-cost, easy to operate, highly efficient, and has promising prospects for industrial application.

[0005] The present invention combines in-situ reaction with reactive infiltration, introduces a reinforcing phase by the in-situ reactive infiltration method, avoids the introduction of impurities in the raw material powder, and obtains particles with uniform particle size. The process is convenient and simple, and industrial production can be realized.

[0006] The present invention provides a method for preparing a SiC / Ti-Si-C composite material, comprising: spreading Ti-Si alloy powder on a SiC / C porous prefabricated body, and performing in-situ reaction infiltration and sintering to prepare the SiC / Ti-Si-C composite material.

[0007] Preferably, the mass fraction of Ti in the Ti-Si alloy is 8 to 30 wt.%; and the particle size of the Ti-Si alloy powder is 3 to 5 mm.

[0008] Preferably, the preparation process of the Ti-Si alloy powder includes:

[0009] (1) Ti particles and Si particles are mixed in proportion and placed in a water-cooled copper crucible, and then cooled to room temperature by vacuum arc melting to obtain an ingot;

[0010] (2) repeating step (1) 5 to 7 times and turning the obtained ingot 180 degrees each time to obtain a Ti-Si eutectic ingot;

[0011] (3) The obtained Ti-Si eutectic ingot is crushed to obtain Ti-Si alloy particles.

[0012] Preferably, the particle size of the Ti particles is 3-5 mm, and the purity is ≥99.9%; the particle size of the Si particles is 3-5 mm, and the purity is ≥99.9%; the parameters of the vacuum arc melting include: vacuum degree of 2×10 -3 ~8×10 -3 Pa; the current range is 120~260A; the temperature of the cooling water used in the water-cooled copper crucible is 22~24℃, and the pressure of the cooling water used is 0.1~0.2MPa.

[0013] Preferably, the SiC / C porous preform has a pore size of 400 nm to 1.5 μm, a porosity of 3.63% to 8.13%, and a thickness of 5 to 10 mm.

[0014] The SiC / C porous preform comprises SiC powder and carbon black, wherein the mass ratio of the SiC powder to the carbon black is (60-85): (8-30);

[0015] The preparation process of the SiC / C porous preform comprises: mixing SiC powder, carbon black and a binder through ball milling, atomizing granulation and molding to obtain the SiC / C porous preform.

[0016] Preferably, the particle size of the SiC powder is 5 to 50 μm, and the purity is ≥99.9%; the particle size of the carbon black is 1 to 5 μm, and the purity is ≥99.9%; the binder is at least one of phenolic resin, PVB, and PVA, preferably phenolic resin; the mass fraction of the binder is 6 to 10 wt.%.

[0017] Preferably, the parameters of the ball milling mixing include: a rotation speed of 300 to 400 r / min and a time of 240 to 300 min.

[0018] Preferably, the forming method includes dry pressing and cold isostatic pressing; the pressure of the dry pressing is 4-6 MPa and the time is 30-60 s; the pressure of the cold isostatic pressing is 180-200 MPa and the time is 10-15 min.

[0019] Preferably, the in-situ reaction infiltration sintering includes: a vacuum atmosphere or an inert atmosphere; a temperature of 1500-1600° C.; and a holding time of 60-120 min; wherein the spreading amount of the Ti-Si alloy particles is 1.5-2.0 times the theoretical calculated value.

[0020] Furthermore, preferably, the in-situ reaction infiltration sintering includes: placing Ti-Si alloy powder on a SiC / C porous preform, heating it to 1100-1200°C at a rate of 8-10°C / min, heating it to 1300-1400°C at a rate of 5-7°C / min, heating it to 1500-1600°C at a rate of 2-3°C / min, keeping it warm for 60-120 minutes, and cooling it to room temperature; the vacuum degree of the vacuum is 5-30Pa.

[0021] Furthermore, preferably, the inert atmosphere is argon or nitrogen, preferably argon.

[0022] In another aspect, the present invention provides a SiC / Ti-Si-C composite material prepared according to the above-described preparation method, wherein the SiC / Ti-Si-C composite material has a flexural strength of 105 to 220 MPa. The SiC / Ti-Si-C composite material prepared by the reactive infiltration sintering method of the present invention has a uniform particle distribution without agglomeration, and the SiC particles are uniformly dispersed in the Ti-Si-C matrix.

[0023] In the present invention, in the low-temperature stage (less than 1200°C) of pressureless reaction infiltration sintering, the temperature is slowly increased relatively quickly. Under the protection of an argon atmosphere or in a vacuum atmosphere, in the medium-temperature stage (1200-1400°C), the temperature is slowly increased to reach the melting point of the Ti-Si alloy to form a molten Ti-Si intermetallic compound. In this stage, the reaction rate is controlled by reducing the heating rate to avoid excessive reaction speed, large heat release, expansion, and increased porosity, thereby ensuring the smooth progress of subsequent densification. As the temperature rises above the melting point or eutectic point of the intermetallic chemical, a Ti-Si liquid phase appears, promoting the dissolution and diffusion of C in SiC. At the same time, the previously molten Ti-Si intermetallic compound dissolves into the porous preform. In addition, after the molten Ti-Si intermetallic compound contacts with C, accompanied by the "dissolution-precipitation" process of the newly generated SiC particles, the green body begins to shrink and the density of the composite material increases. When the sintering temperature reaches 1500-1600°C, the liquid phase sintering process is completed, and the preparation process of the entire SiC / Ti-Si-C composite material is completed.

[0024] Beneficial effects:

[0025] The SiC / Ti-Si-C composite material prepared by the present invention can be used in the fields of aerospace and military, as well as in the fields of transportation, electronic components, fuel cell connectors, semiconductor materials, and the like. In particular, in the semiconductor field, it has an indelible role in promoting the advancement of semiconductor industry production technology and the improvement of production efficiency. Furthermore, the present invention proposes for the first time the use of an in-situ reaction infiltration method to complete the in-situ reaction and densification of the SiC / Ti-Si-C composite material in one step, eliminating the need for complex processes such as high-energy ball milling and pressure sintering. The process is convenient and simple, with low cost, ease of operation, high efficiency, and good prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the micromorphology of the Ti-Si alloy prepared in Example 1;

[0027] Figure 2 This is a process diagram of the reactive infiltration sintering in step (3) of Example 1;

[0028] Figure 3 Microscopic morphology of SiC / Ti-Si-C composite materials prepared in Example 1(a) and Example 2(b);

[0029] Figure 4 This is a schematic diagram showing the residual carbon black particles and the "cooked" phenomenon found after sintering the SiC / Ti-Si-C composite materials prepared in Comparative Examples 1 and 3. DETAILED DESCRIPTION

[0030] To further illustrate the content, features and practical effects of the present invention, the present invention is described in detail below in conjunction with the embodiments. It should be noted that the modification method of the design of the present invention is not limited to these specific embodiments. Without departing from the spirit and connotation of the design of the present invention, equivalent replacements and modifications made by those skilled in the art based on the content of the present invention are also within the scope of the present invention.

[0031] The SiC / Ti-Si-C composite material prepared by the present invention has high electrical conductivity and a controllable thermal expansion coefficient. Its application range is wider than that of traditional SiC composite materials, especially in the field of semiconductor materials.

[0032] The following is an exemplary description of the preparation method of the SiC / Ti-Si-C composite material provided by the present invention.

[0033] Preparation of Ti-Si alloy powder. Ti and Si particles are mixed in a water-cooled copper crucible using vacuum arc melting. The mixture is then cooled to room temperature under vacuum. The ingot is melted 5-7 times using vacuum arc melting equipment, with the ingot flipped 180° each time.

[0034] In an optional embodiment, the Si particles have a particle size of 3 to 5 mm and a purity of ≥99.9%. The Ti particles have a particle size of 3 to 5 mm and a purity of ≥99.9%. The mass fraction of Ti in the Ti-Si alloy is 8 to 30 wt.%.

[0035] The parameters of the vacuum arc melting include: vacuum degree of 2×10 -3 ~8×10 -3 Pa, the current range is 120~260A, the temperature of the copper crucible cooling water is 22~24℃, and the pressure is 0.1~0.2MPa.

[0036] Preparation of SiC / C porous preform: SiC powder, carbon black and binder are mixed in proportion, and the SiC / C porous preform is prepared by ball milling, atomization granulation and molding.

[0037] In an optional embodiment, the SiC powder has a particle size of 5 to 50 μm and a purity of ≥99.9%. The carbon black has a particle size of 1 to 5 μm and a purity of ≥99.9%. The mass ratio of SiC powder to carbon black is (60 to 85):(8 to 30). A SiC powder to carbon black mass ratio that is too high or too low will result in low mechanical properties of the resulting composite material, thus failing to meet practical application requirements.

[0038] The binder is at least one of phenolic resin, PVB, and PVA, and is used to improve the formability of the powder, preferably phenolic resin. The mass fraction of the binder is 6 to 10 wt.%.

[0039] The parameters of the ball milling mixing include: a rotation speed of 300 to 400 r / min and a time of 240 to 300 min.

[0040] The spray granulation parameters include a peristaltic speed of 30 to 60 r / min and a temperature of 90 to 100°C. The molding methods include dry pressing and cold isostatic pressing. The dry pressing method has a pressure of 4 to 6 MPa and a holding time of 30 to 60 seconds, while the cold isostatic pressing method has a pressure of 180 to 200 MPa and a holding time of 10 to 15 minutes.

[0041] Reactive infiltration sintering. The Ti-Si alloy is crushed and spread on a SiC / C porous preform, placed in a vacuum sintering furnace, and heated to 1100-1200°C at a rate of 8-10°C / min under vacuum conditions of 5-30 Pa or inert atmosphere, then heated to 1300-1400°C at a rate of 5-7°C / min, and then heated to 1500-1600°C at a rate of 2-3°C / min, kept warm for 60-120 minutes, and cooled to room temperature; wherein the spreading amount of the Ti-Si alloy particles is 1.5-2.0 times the theoretical calculated value. To ensure that the prepared body can be completely infiltrated by the Ti-Si alloy particles. The inert atmosphere is argon or nitrogen, preferably argon.

[0042] The reactive infiltration of the present invention is heated to the sintering temperature at different heating rates in order to allow the entire reactive infiltration process to proceed more fully. Compared with one-step heating, this method can better control the grain size and phase change, reduce the internal stress during the sintering process, and promote the diffusion of gas. If the heating rate is too low, the sintering time will be prolonged, the sintered body structure will be uneven, and the grain growth will be incomplete, thereby affecting the density and mechanical properties of the material. High-speed heating will cause thermal stress to be quickly generated inside the sintered body, causing uneven thermal expansion of the material, resulting in cracks or deformation of the sintered body. In addition, if the sintering temperature is too high or too low, defects will be present in the material, making it impossible to prepare a composite material with excellent performance.

[0043] In general, selecting an appropriate heating rate during the sintering process of ceramic materials can achieve better grain size control, reduce internal stress accumulation, and promote gas diffusion, thereby improving the properties and quality of the sintered body. However, the optimal heating rate depends on the specific material composition and sintering conditions, and requires experimentation and optimization in practical applications.

[0044] Since the evaporation loss of Ti-Si alloy particles will be taken into account during the reaction process, too little spreading amount will result in the infiltration of the blank, while too much will result in excessive volatile substances being released during the infiltration process and thus contaminating the furnace chamber. Therefore, the spreading amount of Ti-Si alloy particles needs to be 1.5 to 2.0 times the theoretical calculated value. The calculation method for the theoretical value of the required spreading amount of Ti-Si alloy particles is:

[0045] The amount of Ti-Si alloy required during the reaction sintering process consists of two parts: one part is the Ti-Si alloy consumed by the reaction, which is because the green body contains formula carbon and the binder volatilizes to leave residual carbon, which reacts with the Ti-Si alloy infiltrated; the other part is the liquid phase Ti-Si alloy required to fill the voids in the composite material. Therefore, the total amount of Ti-Si alloy required is calculated as follows:

[0046] ① Through the drying and debinding process of pure organic matter, the residual carbon content of organic matter is experimentally determined, and then the amount of carbon added is determined according to the formula. The carbon content of the compact is obtained by adding the two parts. Then according to the reaction formula:

[0047] Si+C→SiC(1-1);

[0048] According to the above formula, the required silicon mass m1 can be calculated based on the molar ratio of Si and C;

[0049] ② Since the pressed green body has a regular shape, the length, width and height of the green body can be measured with a 50-degree vernier caliper to obtain the volume (V) of the green body. The mass of silicon carbide and carbon can be obtained based on the formula. The density of silicon carbide and elemental carbon is 3.26g / cm 3 and 2.28g / cm 3 , calculate the volume V1 and V2 of silicon carbide and carbon in the formula according to V=m / ρ. After subtracting the total volume from the sum of the volumes of silicon carbide and carbon, the approximate pore volume (V 孔 =V-(V1+V2)). In addition, due to the reaction of Si+C→SiC, the volume increases. The amount of silicon carbide generated can be calculated from the molar ratio between the atoms in formula (1-1), and thus the volume of silicon carbide generated can be calculated. The volume increase value V3 can be obtained by subtracting the volume value of silicon carbide from the volume value of elemental carbon. After further calculation, the total volume of the pores in the blank (V 孔 '=V 孔 -V3). In the ideal state, all the voids are filled with liquid pure Ti-Si, so the volume of the Ti-Si alloy filling this part of the void can be obtained (V 孔 '), where the density of Ti is 4.51 g / cm 3 , the density of Si is 2.33 g / cm 3The density of Ti-Si alloy is theoretically calculated based on the actual Ti:Si ratio, and the amount of Ti-Si alloy required for this part can be calculated as m2.

[0050] ③ Adding m1 and m2 in ①② is the ideal amount of Ti-Si alloy required. However, since the reaction sintering temperature is above the melting point of Ti-Si alloy, it is necessary to consider the evaporation loss of silicon. In the actual experiment, it is necessary to add 50% to 100% of the margin. The final calculation shows that the total amount of silicon required is m 总 =(m1+m2)×(1.5~2.0).

[0051] In the present invention, the Ti and SiC contents in the SiC / Ti-Si-C composite material are adjusted by controlling the mass fraction of Ti in the Ti-Si alloy and the ratio of SiC powder and carbon black in the green body, wherein the Ti content in the green body of the SiC / C porous preform is in the range of 8 to 30 wt.%.

[0052] The in-situ reactive infiltration method of the present invention combines an in-situ reaction with pressureless infiltration. Substances within the preform react or react with the infiltrating metal / intermetallic compound to form a reinforcing phase. Simultaneously, the metal / intermetallic compound infiltrates the preform to produce a dense composite material. This method has the following advantages: 1) thermodynamic stability between the generated reinforcing phase and the matrix; 2) fine and uniform particles with a narrow distribution range, which is beneficial for improving the mechanical properties of the composite material; 3) a clean interface between the reinforcing phase particles and the matrix, providing strong bonding; and 4) the ability to produce composite materials containing a high volume fraction (≥50%) of the reinforcing phase. The in-situ reactive infiltration process employed in the present invention combines the in-situ reaction and densification of the SiC / Ti-Si-C composite material in one step, eliminating the need for complex processes such as high-energy ball milling and pressure sintering. The process is convenient and simple, unrestricted by equipment, and low in cost.

[0053] The following examples are further given to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the scope of protection of the present invention. The specific process parameters and the like in the following examples are only examples within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description herein, and are not limited to the specific numerical values ​​exemplified below.

[0054] Example 1

[0055] (1) Preparation of Ti-Si alloy powder: According to the Ti-Si binary phase diagram, Ti particles and Si particles are weighed according to the mass ratio in Table 1 and mechanically mixed, placed in a water-cooled copper crucible, and melted 5 to 7 times using a vacuum arc melting device. Each time, the ingot is turned 180°. Under vacuum conditions, it is naturally cooled to room temperature to complete the preparation of the Ti-Si eutectic ingot. Then, a vibration mill is used to crush the Ti-Si alloy into Ti-Si alloy particles with uniform particle size, and the particle size is 3 to 5 mm. Among them, the particle size of the Si particles used is 3 to 5 mm, and the purity is ≥99.9%; the particle size of the Ti particles is 3 to 5 mm, and the purity is ≥99.9%. The vacuum degree of the arc melting furnace is 5×10 -3 Pa, current 200A, cooling water temperature of the copper crucible 22℃, cooling water pressure 0.1MPa.

[0056] (2) Preparation of green bodies: ① Preparation of mixed powder: SiC powder (particle size 5-50 μm, purity ≥99.9%), carbon black (particle size 1-5 μm, purity ≥99.9%) and 8 wt.% of phenolic resin were mixed uniformly in a planetary ball mill using ethanol as solvent, and the ball-milled slurry was atomized into a mixed powder of uniform size by atomization granulation; ② Pressing of green bodies: The mixed powder obtained in ① was loaded into a rectangular mold of 36.00×52.00 mm, and a pressure of 4 MPa was applied and maintained for 60 s to prepare a rectangular pressed tablet sample of 36.00×52.00 mm, and the sample was cold isostatically pressed (pressure of 200 MPa, holding pressure for 15 min) to prepare a SiC / C porous preform (pore size of 800 nm-1.5 μm, porosity of 5.62%, thickness of 5 mm).

[0057] The raw materials and proportions used in this embodiment 1 are shown in Table 1:

[0058] name Particle size Ratio (wt.%) Ti 3~5mm 15.00 Si 3~5mm 85.00 SiC 10μm 77.50 carbon black 1~5μm 14.50 Phenolic resin — 8.00

[0059] (3) Reaction infiltration sintering: The uniformly sized Ti-Si alloy particles obtained in step (1) are laid on the SiC / C porous preform prepared in step (2). The amount of Ti-Si alloy particles required is calculated theoretically, and 1.5 to 2.0 times the theoretically required Ti-Si alloy particles are laid to ensure that the blank can be completely infiltrated. The blank is placed in a crucible and loaded into a vacuum sintering furnace. Under a vacuum condition of 10 Pa, the temperature is raised to 1200°C at 10°C / min, then to 1400°C at 5°C / min, and finally to 1550°C at 3°C / min. The temperature is kept at this temperature for 120 minutes, and finally cooled to room temperature with the furnace to complete the entire reaction infiltration process.

[0060] Figure 3(a) shows the microscopic morphology of the SiC / Ti-Si-C composite material prepared in Example 1. The figure shows that the SiC powder size is 10 μm, and no residual carbon black particles are observed after sintering. The SiC particles are evenly distributed within the Ti-Si-C matrix, and the interface between the particles and the matrix is ​​clean, tightly bonded, and free of agglomeration. The SiC / Ti-Si-C composite material prepared in Example 1 has a flexural strength of 183 MPa.

[0061] Example 2

[0062] (1) Preparation of Ti-Si alloy powder: According to the Ti-Si binary phase diagram, Ti particles and Si particles are weighed according to the mass ratio in Table 2 and mechanically mixed, placed in a water-cooled copper crucible, and melted 5 to 7 times using a vacuum arc melting device. Each time, the ingot is turned 180°. Under vacuum conditions, it is naturally cooled to room temperature to complete the preparation of the Ti-Si eutectic ingot. Then, a vibration mill is used to crush the Ti-Si alloy into Ti-Si alloy particles with uniform particle size, and the particle size is 3 to 5 mm. Among them, the particle size of the Si particles used is 3 to 5 mm, and the purity is ≥99.9%; the particle size of the Ti particles is 3 to 5 mm, and the purity is ≥99.9%. The vacuum degree of the arc melting furnace is 8×10 -3 Pa, current 220A, cooling water temperature of the copper crucible 23 °C, cooling water pressure 0.15MPa.

[0063] (2) Preparation of green bodies: ① Preparation of mixed powder: SiC powder (particle size 5-50 μm, purity ≥99.9%), carbon black (particle size 1-5 μm, purity ≥99.9%) and 8 wt.% of phenolic resin were mixed uniformly in a planetary ball mill using ethanol as solvent, and the obtained slurry was atomized into a mixed powder of uniform size by atomization granulation; ② Pressing of green bodies: The mixed powder obtained in ① was loaded into a rectangular mold of 36.00×52.00 mm, and a pressure of 4 MPa was applied and maintained for 60 s to prepare a rectangular tablet sample of 36.00×52.00 mm, and the sample was cold isostatically pressed (pressure of 200 MPa, holding pressure for 15 min) to prepare a SiC / C porous preform (pore size of 400 nm-980 nm, porosity of 3.63%, thickness of 8 mm).

[0064] The raw materials and proportions used in this Example 2 are shown in Table 2:

[0065] name Particle size Ratio (wt.%) Ti 3~5mm 15.00 Si 3~5mm 85.00 SiC 5μm 83.42 carbon black 1~5μm 8.58 Phenolic resin — 8.00

[0066] (3) Reaction infiltration sintering: The uniformly sized Ti-Si alloy particles obtained in step (1) are laid on the SiC / C porous preform prepared in step (2). The amount of Ti-Si alloy particles required is calculated theoretically, and 1.5 to 2.0 times the theoretically required Ti-Si alloy particles are laid out and placed in a crucible and loaded into a vacuum sintering furnace. Under a vacuum condition of 5 Pa, the temperature is raised to 1200°C at 10°C / min, then to 1400°C at 5°C / min, and finally to 1600°C at 3°C / min, and the temperature is kept at this temperature for 120 minutes. Finally, the crucible is cooled to room temperature to complete the entire reaction infiltration process.

[0067] Figure 3 (b) Microscopic morphology of the SiC / Ti-Si-C composite material prepared in Example 2. The figure shows that the SiC powder size is 5 μm, no residual carbon black particles are found after sintering, and the SiC particles are evenly distributed within the Ti-Si-C matrix. The interface between the particles and the matrix is ​​clean, tightly bonded, and free of agglomeration. The SiC / Ti-Si-C composite material prepared in Example 2 has a flexural strength of 220 MPa.

[0068] Example 3

[0069] (1) Preparation of Ti-Si alloy powder: According to the Ti-Si binary phase diagram, Ti particles and Si particles are weighed according to the mass ratio in Table 3 and mechanically mixed, placed in a water-cooled copper crucible, and melted 5 to 7 times using a vacuum arc melting device. Each time, the ingot is turned 180°. Under vacuum conditions, it is naturally cooled to room temperature to complete the preparation of the Ti-Si eutectic ingot. Then, a vibration mill is used to crush the Ti-Si alloy into Ti-Si alloy particles with uniform particle size, and the particle size is 3 to 5 mm. Among them, the particle size of the Si particles used is 3 to 5 mm, and the purity is ≥99.9%; the particle size of the Ti particles is 3 to 5 mm, and the purity is ≥99.9%. The vacuum degree of the arc melting furnace is 2×10 -3 Pa, current 180A, cooling water temperature of copper crucible 22℃, cooling water pressure 0.2MPa.

[0070] (2) Preparation of green bodies: ① Preparation of mixed powder: SiC powder (particle size 5-50 μm, purity ≥99.9%), carbon black (particle size 1-5 μm, purity ≥99.9%) and 8 wt.% of phenolic resin were mixed uniformly in a planetary ball mill using ethanol as solvent, and the obtained slurry was atomized into a mixed powder of uniform size by atomization granulation; ② Pressing of green bodies: The mixed powder obtained in ① was loaded into a rectangular mold of 36.00×52.00 mm, and a pressure of 4 MPa was applied and maintained for 60 s to prepare a rectangular tablet sample of 36.00×52.00 mm, and the sample was cold isostatically pressed (pressure of 200 MPa, holding pressure for 15 min) to prepare a SiC / C porous preform (pore size of 800 nm-1.2 μm, porosity of 4.15%, and thickness of 7 mm).

[0071] The raw materials and proportions used in this embodiment 3 are shown in Table 3:

[0072] name Particle size Ratio (wt.%) Ti 3~5mm 20.00 Si 3~5mm 80.00 SiC 5μm 83.42 carbon black 1~5μm 8.58 Phenolic resin — 8.00

[0073] (3) Reaction infiltration sintering: The uniformly sized Ti-Si alloy particles obtained in step (1) are laid on the SiC / C porous preform prepared in step (2). The amount of Ti-Si alloy particles required is calculated theoretically, and 1.5 to 2.0 times the theoretically required Ti-Si alloy particles are laid to ensure that the blank can be completely infiltrated. The blank is placed in a crucible and loaded into a vacuum sintering furnace. Under a vacuum condition of 5 Pa, the temperature is raised to 1200°C at 10°C / min, then to 1400°C at 5°C / min, and finally to 1550°C at 3°C / min. The temperature is kept at this temperature for 90 minutes, and finally cooled to room temperature with the furnace to complete the entire reaction infiltration process.

[0074] After sintering, the SiC / Ti-Si-C composite material prepared in Example 3 showed no residual carbon black particles. The SiC particles were evenly distributed within the Ti-Si-C matrix, and the interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. The SiC / Ti-Si-C composite material prepared in Example 3 exhibited a flexural strength of 170 MPa.

[0075] Example 4

[0076] (1) Preparation of Ti-Si alloy powder: According to the Ti-Si binary phase diagram, Ti particles and Si particles are weighed according to the mass ratio in Table 4 and mechanically mixed, placed in a water-cooled copper crucible, and melted 5 to 7 times using a vacuum arc melting device. Each time, the ingot is turned 180°. Under vacuum conditions, it is naturally cooled to room temperature to complete the preparation of the Ti-Si eutectic ingot. Then, a vibration mill is used to crush the Ti-Si alloy into Ti-Si alloy particles with uniform particle size, and the particle size is 3 to 5 mm. Among them, the particle size of the Si particles used is 3 to 5 mm, and the purity is ≥99.9%; the particle size of the Ti particles is 3 to 5 mm, and the purity is ≥99.9%. The vacuum degree of the arc melting furnace is 3×10 -3 Pa, current 230A, cooling water temperature of copper crucible 23℃, cooling water pressure 0.2MPa.

[0077] (2) Preparation of green bodies: ① Preparation of mixed powder: SiC powder (particle size 5-50 μm, purity ≥99.9%), carbon black (particle size 1-5 μm, purity ≥99.9%) and 8 wt.% of phenolic resin were mixed uniformly in a planetary ball mill using ethanol as solvent, and the obtained slurry was atomized into a mixed powder of uniform size by atomization granulation; ② Pressing of green bodies: The mixed powder obtained in ① was loaded into a rectangular mold of 36.00×52.00 mm, and a pressure of 6 MPa was applied and maintained for 30 s to prepare a rectangular tablet sample of 36.00×52.00 mm, and the sample was cold isostatically pressed (pressure of 180 MPa, holding pressure for 15 min) to prepare a SiC / C porous preform (pore size of 500 nm-1.3 μm, porosity of 6.13%, thickness of 9 mm).

[0078] The raw materials and proportions used in this embodiment 4 are shown in Table 4:

[0079] name Particle size Ratio (wt.%) Ti 3~5mm 15.00 Si 3~5mm 85.00 SiC 5μm 64.50 carbon black 1~5μm 27.50 Phenolic resin — 8.00

[0080] (3) Reaction infiltration sintering: The uniformly sized Ti-Si alloy particles obtained in step (1) are laid on the SiC / C porous preform prepared in step (2). The amount of Ti-Si alloy particles required is calculated theoretically, and 1.5 to 2.0 times the theoretically required Ti-Si alloy particles are laid to ensure that the blank can be completely infiltrated. The blank is placed in a crucible and loaded into a vacuum sintering furnace. Under a vacuum condition of 5 Pa, the temperature is raised to 1200°C at 10°C / min, then to 1400°C at 5°C / min, and finally to 1600°C at 3°C / min. The temperature is kept at this temperature for 90 minutes, and finally cooled to room temperature with the furnace to complete the entire reaction infiltration process.

[0081] After sintering, the SiC / Ti-Si-C composite material prepared in Example 4 showed no residual carbon black particles. The SiC particles were evenly distributed within the Ti-Si-C matrix, and the interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. The SiC / Ti-Si-C composite material prepared in Example 4 exhibited a flexural strength of 165 MPa.

[0082] Example 5

[0083] (1) Preparation of Ti-Si alloy powder: According to the Ti-Si binary phase diagram, Ti particles and Si particles are weighed according to the mass ratio in Table 5 and mechanically mixed, placed in a water-cooled copper crucible, and melted 5 to 7 times using a vacuum arc melting device. Each time, the ingot is turned 180°. Under vacuum conditions, it is naturally cooled to room temperature to complete the preparation of the Ti-Si eutectic ingot. Then, a vibration mill is used to crush the Ti-Si alloy into Ti-Si alloy particles with uniform particle size, and the particle size is 3 to 5 mm. Among them, the particle size of the Si particles used is 3 to 5 mm, and the purity is ≥99.9%; the particle size of the Ti particles is 3 to 5 mm, and the purity is ≥99.9%. The vacuum degree of the arc melting furnace is 8×10 -3 Pa, current 160A, cooling water temperature of the copper crucible 23 °C, cooling water pressure 0.2MPa.

[0084] (2) Preparation of green bodies: ① Preparation of mixed powder: SiC powder (particle size 5-50 μm, purity ≥99.9%), carbon black (particle size 1-5 μm, purity ≥99.9%) and 8 wt.% of phenolic resin were mixed uniformly in a planetary ball mill using ethanol as solvent, and the obtained slurry was atomized into a mixed powder of uniform size by atomization granulation; ② Pressing of green bodies: The mixed powder obtained in ① was loaded into a rectangular mold of 36.00×52.00 mm, and a pressure of 6 MPa was applied and maintained for 30 s to prepare a rectangular tablet sample of 36.00×52.00 mm, and the sample was cold isostatically pressed (pressure of 180 MPa, holding pressure for 15 min) to prepare a SiC / C porous preform (pore size of 400 nm-1.0 μm, porosity of 5.13%, thickness of 10 mm).

[0085] The raw materials and proportions used in this embodiment 5 are shown in Table 5:

[0086] name Particle size Ratio (wt.%) Ti 3~5mm 30.00 Si 3~5mm 70.00 SiC 5μm 70.50 carbon black 1~5μm 21.50 Phenolic resin — 8.00

[0087] (3) Reaction infiltration sintering: The uniformly sized Ti-Si alloy particles obtained in step (1) are laid on the SiC / C porous preform prepared in step (2). The amount of Ti-Si alloy particles required is calculated theoretically, and 1.5 to 2.0 times the theoretically required Ti-Si alloy particles are laid to ensure that the blank can be completely infiltrated. The blank is placed in a crucible and loaded into a vacuum sintering furnace. Under a vacuum condition of 5 Pa, the temperature is raised to 1200°C at 10°C / min, then to 1400°C at 5°C / min, and finally to 1600°C at 3°C / min. The temperature is kept at this temperature for 120 minutes, and finally cooled to room temperature with the furnace to complete the entire reaction infiltration process.

[0088] After sintering, the SiC / Ti-Si-C composite material prepared in Example 5 showed no residual carbon black particles. The SiC particles were evenly distributed within the Ti-Si-C matrix, and the interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. The SiC / Ti-Si-C composite material prepared in Example 5 exhibited a flexural strength of 142 MPa.

[0089] Example 6

[0090] (1) Preparation of Ti-Si alloy powder: According to the Ti-Si binary phase diagram, Ti particles and Si particles are weighed according to the mass ratio in Table 6 and mechanically mixed, placed in a water-cooled copper crucible, and melted 5 to 7 times using a vacuum arc melting device. Each time, the ingot is turned 180°. Under vacuum conditions, it is naturally cooled to room temperature to complete the preparation of the Ti-Si eutectic ingot. Then, a vibration mill is used to crush the Ti-Si alloy into Ti-Si alloy particles with uniform particle size, and the particle size is 3 to 5 mm. Among them, the particle size of the Si particles used is 3 to 5 mm, and the purity is ≥99.9%; the particle size of the Ti particles is 3 to 5 mm, and the purity is ≥99.9%. The vacuum degree of the arc melting furnace is 4×10 -3 Pa, current 250A, cooling water temperature of the copper crucible 23℃, cooling water pressure 0.2MPa.

[0091] (2) Preparation of green bodies: ① Preparation of mixed powder: SiC powder (particle size 5-50 μm, purity ≥99.9%), carbon black (particle size 1-5 μm, purity ≥99.9%) and 8 wt.% of phenolic resin were mixed uniformly in a planetary ball mill using ethanol as solvent, and the obtained slurry was atomized into a mixed powder of uniform size by atomization granulation; ② Pressing of green bodies: The mixed powder obtained in ① was loaded into a rectangular mold of 36.00×52.00 mm, and a pressure of 6 MPa was applied and maintained for 30 s to prepare a rectangular tablet sample of 36.00×52.00 mm, and the sample was cold isostatically pressed (pressure of 180 MPa, holding pressure for 15 min) to prepare a SiC / C porous preform (pore size of 1.1 μm-1.5 μm, porosity of 6.89%, thickness of 5 mm).

[0092] The raw materials and proportions used in this Example 6 are shown in Table 6:

[0093] name Particle size Ratio (wt.%) Ti 3~5mm 25.00 Si 3~5mm 75.00 SiC 5μm 67.50 carbon black 1~5μm 24.50 Phenolic resin — 8.00

[0094] (3) Reaction infiltration sintering: The uniformly sized Ti-Si alloy particles obtained in step (1) are laid on the SiC / C porous preform prepared in step (2). The amount of Ti-Si alloy particles required is calculated theoretically, and 1.5 to 2.0 times the theoretically required Ti-Si alloy particles are laid to ensure that the blank can be completely infiltrated. The blank is placed in a crucible and loaded into a vacuum sintering furnace. Under a vacuum condition of 5 Pa, the temperature is raised to 1200°C at 10°C / min, then to 1400°C at 5°C / min, and finally to 1600°C at 3°C / min. The temperature is kept at this temperature for 90 minutes, and finally cooled to room temperature with the furnace to complete the entire reaction infiltration process.

[0095] After sintering, the SiC / Ti-Si-C composite material prepared in Example 6 showed no residual carbon black particles. The SiC particles were evenly distributed within the Ti-Si-C matrix, and the interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. The SiC / Ti-Si-C composite material prepared in Example 6 exhibited a flexural strength of 148 MPa.

[0096] Example 7

[0097] (1) Preparation of Ti-Si alloy powder: According to the Ti-Si binary phase diagram, Ti particles and Si particles are weighed according to the mass ratio in Table 7 and mechanically mixed, placed in a water-cooled copper crucible, and melted 5 to 7 times using a vacuum arc melting device. Each time, the ingot is turned 180°. Under vacuum conditions, it is naturally cooled to room temperature to complete the preparation of the Ti-Si eutectic ingot. Then, a vibration mill is used to crush the Ti-Si alloy into Ti-Si alloy particles with uniform particle size, and the particle size is 3 to 5 mm. Among them, the particle size of the Si particles used is 3 to 5 mm, and the purity is ≥99.9%; the particle size of the Ti particles is 3 to 5 mm, and the purity is ≥99.9%. The vacuum degree of the arc melting furnace is 5×10 -3 Pa, current 260A, cooling water temperature of the copper crucible 24℃, cooling water pressure 0.1MPa.

[0098] (2) Preparation of green bodies: ① Preparation of mixed powder: SiC powder (particle size 5-50 μm, purity ≥99.9%); carbon black (particle size 1-5 μm, purity ≥99.9%), the three powders and 8 wt.% of phenolic resin were mixed uniformly in a planetary ball mill with ethanol as solvent, and the obtained slurry was atomized into a mixed powder of uniform size by atomization granulation; ② Pressing of green bodies: The mixed powder obtained in ① was loaded into a rectangular mold of 36.00×52.00 mm, and a pressure of 6 MPa was applied and maintained for 30 s to prepare a rectangular tablet sample of 36.00×52.00 mm, and the sample was cold isostatically pressed (pressure of 180 MPa, holding pressure for 15 min) to prepare a SiC / C porous preform (pore size of 900 nm-1.3 μm, porosity of 7.56%, thickness of 6 mm).

[0099] The raw materials and proportions used in this Example 7 are shown in Table 7:

[0100] name Particle size Ratio (wt.%) Ti 3~5mm 25.00 Si 3~5mm 75.00 SiC 5μm 73.50 carbon black 1~5μm 18.50 Phenolic resin — 8.00

[0101] (3) Reaction infiltration sintering: The uniformly sized Ti-Si alloy particles obtained in step (1) are laid on the SiC / C porous preform prepared in step (2). The amount of Ti-Si alloy particles required is calculated theoretically, and 1.5 to 2.0 times the theoretically required Ti-Si alloy particles are laid to ensure that the blank can be completely infiltrated. The blank is placed in a crucible and loaded into a vacuum sintering furnace. Under a vacuum condition of 5 Pa, the temperature is raised to 1200°C at 10°C / min, then to 1400°C at 5°C / min, and finally to 1600°C at 3°C / min. The temperature is kept at this temperature for 90 minutes, and finally cooled to room temperature with the furnace to complete the entire reaction infiltration process.

[0102] After sintering, the SiC / Ti-Si-C composite material prepared in Example 7 showed no residual carbon black particles. The SiC particles were evenly distributed within the Ti-Si-C matrix, and the interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. The SiC / Ti-Si-C composite material prepared in Example 7 exhibited a flexural strength of 153 MPa.

[0103] Example 8

[0104] (1) Preparation of Ti-Si alloy powder: According to the Ti-Si binary phase diagram, Ti particles and Si particles are weighed according to the mass ratio in Table 8 and mechanically mixed, placed in a water-cooled copper crucible, and melted 5 to 7 times using a vacuum arc melting device. Each time, the ingot is turned 180°. Under vacuum conditions, it is naturally cooled to room temperature to complete the preparation of the Ti-Si eutectic ingot. Then, a vibration mill is used to crush the Ti-Si alloy into Ti-Si alloy particles with uniform particle size, and the particle size is 3 to 5 mm. Among them, the particle size of the Si particles used is 3 to 5 mm, and the purity is ≥99.9%; the particle size of the Ti particles is 3 to 5 mm, and the purity is ≥99.9%. The vacuum degree of the arc melting furnace is 3×10 -3 Pa, current 170A, cooling water temperature of copper crucible 23℃, cooling water pressure 0.2MPa.

[0105] (2) Preparation of green bodies: ① Preparation of mixed powder: SiC powder (particle size 5-50 μm, purity ≥99.9%), carbon black (particle size 1-5 μm, purity ≥99.9%) and 8 wt.% of phenolic resin were mixed uniformly in a planetary ball mill using ethanol as solvent, and the obtained slurry was atomized into a mixed powder of uniform size by atomization granulation; ② Pressing of green bodies: The mixed powder obtained in ① was loaded into a rectangular mold of 36.00×52.00 mm, and a pressure of 6 MPa was applied and maintained for 30 s to prepare a rectangular tablet sample of 36.00×52.00 mm, and the sample was cold isostatically pressed (pressure of 180 MPa, holding pressure for 15 min) to prepare a SiC / C porous preform (pore size of 600 nm-1.2 μm, porosity of 4.56%, thickness of 8 mm).

[0106] The raw materials and proportions used in this Example 8 are shown in Table 8:

[0107] name Particle size Ratio (wt.%) Ti 3~5mm 15.00 Si 3~5mm 85.00 SiC 5μm 82.50 carbon black 1~5μm 9.50 Phenolic resin — 8.00

[0108] (3) Reaction infiltration sintering: The uniformly sized Ti-Si alloy particles obtained in step (1) are laid on the SiC / C porous preform prepared in step (2). The amount of Ti-Si alloy particles required is calculated theoretically, and 1.5 to 2.0 times the theoretically required Ti-Si alloy particles are laid to ensure that the blank can be completely infiltrated. The blank is placed in a crucible and loaded into a vacuum sintering furnace. Under a vacuum condition of 5 Pa, the temperature is raised to 1200°C at 10°C / min, then to 1400°C at 5°C / min, and finally to 1500°C at 3°C / min. The temperature is kept at this temperature for 90 minutes, and finally cooled to room temperature with the furnace to complete the entire reaction infiltration process.

[0109] After sintering, the SiC / Ti-Si-C composite material prepared in Example 8 showed no residual carbon black particles. The SiC particles were evenly distributed within the Ti-Si-C matrix, and the interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. The SiC / Ti-Si-C composite material prepared in Example 8 exhibited a flexural strength of 135 MPa.

[0110] Example 9

[0111] The preparation process of the SiC / Ti-Si-C composite material in this Example 9 refers to that in Example 1, the only difference is that in step (2) of preparing the SiC / C porous preform, the particle size of the SiC powder is 5 μm.

[0112] No residual carbon black particles were found in the SiC / Ti-Si-C composite material prepared in this Example 9 after sintering. The SiC particles were evenly distributed in the Ti-Si-C matrix. The interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. The flexural strength of the SiC / Ti-Si-C composite material reached 163 MPa.

[0113] Example 10

[0114] The preparation process of the SiC / Ti-Si-C composite material in this Example 10 refers to that in Example 1, the only difference is that in step (2) of preparing the SiC / C porous preform, the particle size of the SiC powder is 50 μm.

[0115] No residual carbon black particles were found in the SiC / Ti-Si-C composite material prepared in Example 10 after sintering, the SiC particles were evenly distributed in the Ti-Si-C matrix, the interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration, and the flexural strength of the SiC / Ti-Si-C composite material reached 116 MPa.

[0116] Example 11

[0117] The preparation process of the SiC / Ti-Si-C composite material in this Example 11 refers to that in Example 1, the only difference is that in step (3) reactive infiltration sintering, the sintering temperature is 1600° C. and the temperature is kept for 90 minutes.

[0118] No residual carbon black particles were found in the SiC / Ti-Si-C composite material prepared in this Example 11 after sintering. The SiC particles were evenly distributed in the Ti-Si-C matrix. The interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. The flexural strength of the SiC / Ti-Si-C composite material reached 142 MPa.

[0119] Example 12

[0120] The preparation process of the SiC / Ti-Si-C composite material in this Example 12 refers to that in Example 1, the only difference is that in step (3) reactive infiltration sintering, the sintering temperature is 1600° C. and the temperature is kept for 120 minutes.

[0121] No residual carbon black particles were found in the SiC / Ti-Si-C composite material prepared in this Example 12 after sintering. The SiC particles were evenly distributed in the Ti-Si-C matrix. The interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. The flexural strength of the SiC / Ti-Si-C composite material reached 168 MPa.

[0122] Example 13

[0123] The preparation process of the SiC / Ti-Si-C composite material in this Example 13 refers to that in Example 1, the only difference is that in step (3) reactive infiltration sintering, the sintering temperature is 1500° C. and the temperature is kept for 60 minutes.

[0124] No residual carbon black particles were found in the SiC / Ti-Si-C composite material prepared in this Example 13 after sintering, the SiC particles were evenly distributed in the Ti-Si-C matrix, the interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration, and the flexural strength of the SiC / Ti-Si-C composite material reached 105 MPa.

[0125] Example 14

[0126] The preparation process of the SiC / Ti-Si-C composite material in this Example 14 refers to that in Example 1, the only difference is that in step (3) reactive infiltration sintering, the sintering temperature is 1500° C. and the temperature is kept for 90 minutes.

[0127] No residual carbon black particles were found in the SiC / Ti-Si-C composite material prepared in Example 14 after sintering. The SiC particles were evenly distributed in the Ti-Si-C matrix. The interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. The flexural strength of the SiC / Ti-Si-C composite material reached 114 MPa.

[0128] Example 15

[0129] The preparation process of the SiC / Ti-Si-C composite material in this Example 15 refers to that in Example 1, the only difference is that in step (3) reactive infiltration sintering, the sintering temperature is 1500° C. and the temperature is kept for 120 minutes.

[0130] No residual carbon black particles were found in the SiC / Ti-Si-C composite material prepared in this Example 15 after sintering, the SiC particles were evenly distributed in the Ti-Si-C matrix, the interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration, and the flexural strength of the SiC / Ti-Si-C composite material reached 126 MPa.

[0131] Example 16

[0132] The preparation process of the SiC / Ti-Si-C composite material in this Example 16 refers to that in Example 1, the only difference is that in step (3) reactive infiltration sintering, the sintering temperature is 1550° C. and the temperature is kept for 60 minutes.

[0133] No residual carbon black particles were found in the SiC / Ti-Si-C composite material prepared in Example 16 after sintering, the SiC particles were evenly distributed in the Ti-Si-C matrix, the interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration, and the flexural strength of the SiC / Ti-Si-C composite material reached 138 MPa.

[0134] Comparative Example 1

[0135] The preparation process of the SiC / Ti-Si-C composite material in this comparative example 1 refers to that in Example 1, with the only difference being that in step (3) reactive infiltration sintering, the uniformly sized Ti-Si alloy particles prepared in step (1) are placed on the body of the SiC / C porous preform prepared in step (2), wherein the amount of the required Ti-Si alloy particles (1 times) is calculated according to theory, and the theoretically required Ti-Si alloy particles are placed.

[0136] After sintering, the SiC / Ti-Si-C composite material prepared in Comparative Example 1 contained residual carbon black particles and a "cooked" phenomenon. Figure 4As shown in the figure, the Ti-Si alloy particles did not penetrate the SiC / C porous preform. This phenomenon occurs because the Ti-Si alloy particles volatilize or react with the graphite crucible during the reactive infiltration process. Therefore, 1.5 to 2.0 times the theoretically required Ti-Si alloy particles are placed during the reactive infiltration process to ensure that the preform can be completely infiltrated.

[0137] Comparative Example 2

[0138] The preparation process of the SiC / Ti-Si-C composite material in this comparative example 2 refers to that in Example 1, the only difference is that in the preparation of the blank in step (2), SiC:C=54.5:37.5 (as shown in Table 9).

[0139] The raw materials and proportions used in this comparative example 2 are shown in Table 9:

[0140] name Particle size Ratio (wt.%) Ti 3~5mm 15.00 Si 3~5mm 85.00 SiC 10μm 54.50 carbon black 1~5μm 37.50 Phenolic resin — 8.00

[0141] After sintering, residual carbon black particles were found in the SiC / Ti-Si-C composite material prepared in Comparative Example 2, and there was a "cooked" phenomenon. This phenomenon occurred because during the reactive infiltration process, the Ti-Si alloy particles did not melt into the body of the SiC / C porous preform. Therefore, during the reactive infiltration process, the SiC:C ratio needs to be within a certain range to ensure that the body can be completely infiltrated.

[0142] Comparative Example 3

[0143] The preparation process of the SiC / Ti-Si-C composite material in this comparative example 3 refers to that in Example 1, the only difference is that in step (3) the reaction infiltration sintering, the sintering temperature is 1400° C. and the heat preservation time is 120 min.

[0144] After sintering, the SiC / Ti-Si-C composite material prepared in Comparative Example 3 was found to have residual carbon black particles and a "cooked" phenomenon. The Ti-Si alloy particles did not melt-infiltrate the SiC / C porous preform. This phenomenon occurred because during the reaction infiltration process, due to the low temperature, the reaction process was incomplete, and the Ti-Si alloy particles could not further react with the porous preform. Figure 4 As shown, there is a "cooked" phenomenon in the middle.

[0145] Comparative Example 4

[0146] The preparation process of the SiC / Ti-Si-C composite material in this comparative example 4 refers to that in Example 1, the only difference is that in step (3) reactive infiltration sintering, the sintering temperature is 1700° C. and the temperature is kept for 120 min.

[0147] After sintering, residual carbon black particles were found in the SiC / Ti-Si-C composite material prepared in Comparative Example 4. The SiC particles were evenly distributed in the Ti-Si-C matrix. The interface between the particles and the matrix was clean, tightly bonded, and free of agglomeration. Its microstructure was not significantly different from that in Example 1. However, its flexural strength only reached 68 MPa, which was caused by the high temperature affecting its recrystallization process.

[0148] Table 10 shows the composition and reactive infiltration sintering parameters of the SiC / Ti-Si-C composite materials prepared in Examples 1-16 and Comparative Examples 1-2:

[0149] Ti:Si / wt% SiC:C / wt% SiC particle size / μm Infiltration parameters Bending strength / MPa Example 1 15:85 77.5:14.5 10 1550℃ / 120min 183 Example 2 15:85 83.42:8.58 5 1600℃ / 120min 220 Example 3 20:80 83.42:8.58 5 1550℃ / 90min 170 Example 4 15:85 64.5:27.5 5 1600℃ / 90min 165 Example 5 30:70 70.5:21.5 5 1600℃ / 120min 142 Example 6 25:75 67.5:24.5 5 1600℃ / 90min 148 Example 7 25:75 73.5:18.5 5 1600℃ / 90min 153 Example 8 15:85 82.5:9.5 5 1500℃ / 90min 135 Example 9 15:85 77.5:14.5 10 1550℃ / 120min 163 Example 10 15:85 77.5:14.5 50 1550℃ / 120min 116 Example 11 15:85 77.5:14.5 10 1600℃ / 90min 142 Example 12 15:85 77.5:14.5 10 1600℃ / 120min 168 Example 13 15:85 77.5:14.5 10 1500℃ / 60min 105 Example 14 15:85 77.5:14.5 10 1500℃ / 90min 114 Example 15 15:85 77.5:14.5 10 1500℃ / 120min 126 Example 16 15:85 77.5:14.5 10 1550℃ / 60min 138 Comparative Example 1 15:85 77.5:14.5 10 1550℃ / 120min — Comparative Example 2 15:85 54.5:37.5 10 1550℃ / 120min — Comparative Example 3 15:85 77.5:14.5 10 1400℃ / 120min — Comparative Example 4 15:85 77.5:14.5 10 1700℃ / 120min 68

[0150] As shown in the table, by comparing Examples 1-16, it is found that the mechanical properties of the SiC / Ti-Si-C composite material prepared in Example 2 are the best. This shows that when the Ti:Si mass ratio is 15:85, the SiC:C mass ratio is 83.42:8.58, and the SiC particle size is 5μm, a SiC / Ti-Si-C composite material with excellent performance can be obtained. In addition, Comparative Examples 1-4 show that the SiC:C mass ratio is not within the range of the present invention, too few Ti-Si alloy particles, and too high or too low a sintering temperature can affect the performance of the prepared SiC / Ti-Si-C composite material.

Claims

1. A method for preparing a SiC / Ti-Si-C composite material, characterized in that: include: The SiC / Ti-Si-C composite material is prepared by spreading Ti-Si alloy powder onto a SiC / C porous preform and performing in-situ reaction infiltration and sintering; wherein, The mass fraction of Ti in the Ti-Si alloy is 8 to 30 wt.%; The SiC / C porous preform comprises SiC powder and carbon black, wherein the mass ratio of the SiC powder to the carbon black is (60-85): (8-30); The spreading amount of Ti-Si alloy particles is 1.5 to 2.0 times the theoretical calculated value; The in-situ reaction infiltration sintering includes: in a vacuum or inert atmosphere, heating to 1100-1200°C at a rate of 8-10°C / min, heating to 1300-1400°C at a rate of 5-7°C / min, heating to 1500-1600°C at a rate of 2-3°C / min, keeping warm for 60-120 minutes, and cooling to room temperature; the vacuum degree of the vacuum is 5-30 Pa.

2. The preparation method according to claim 1, characterized in that The particle size of the Ti-Si alloy powder is 3 to 5 mm.

3. The preparation method according to claim 2, characterized in that The preparation process of the Ti-Si alloy powder comprises: (1) Ti particles and Si particles are mixed in proportion and placed in a water-cooled copper crucible. After vacuum arc melting, the mixture is cooled to room temperature to obtain an ingot. (2) Repeat step (1) 5 to 7 times and flip the obtained ingot 180 degrees each time to obtain a Ti-Si eutectic ingot; (3) The obtained Ti-Si eutectic ingot is crushed to obtain Ti-Si alloy particles.

4. The preparation method according to claim 3, characterized in that The particle size of the Ti particles is 3 to 5 mm, and the purity is ≥99.9%; the particle size of the Si particles is 3 to 5 mm, and the purity is ≥99.9%; The parameters of the vacuum arc melting include: vacuum degree of 2×10 -3 ~8×10 -3 Pa; the current range is 120~260A; the temperature of the cooling water used for the water-cooled copper crucible is 22~24℃, and the pressure of the cooling water used is 0.1~0.2MPa.

5. The preparation method according to claim 1, characterized in that The SiC / C porous preform has a pore size of 400 nm to 1.5 μm, a porosity of 3.63 to 8.13%, and a thickness of 5 to 10 mm. The preparation process of the SiC / C porous preform comprises: mixing SiC powder, carbon black and a binder through ball milling, atomizing granulation and molding to obtain the SiC / C porous preform.

6. The preparation method according to claim 5, characterized in that The particle size of the SiC powder is 5 to 50 μm, and the purity is ≥99.9%; the particle size of the carbon black is 1 to 5 μm, and the purity is ≥99.9%; The binder is at least one of phenolic resin, PVB, and PVA; the mass fraction of the binder is 6 to 10 wt.% of the total mass of SiC powder and carbon black.

7. The preparation method according to claim 6, characterized in that The binder is phenolic resin.

8. The preparation method according to claim 5, wherein The parameters of the ball milling mixing include: a rotation speed of 300 to 400 r / min and a time of 240 to 300 min; The parameters of the spray granulation include: creep speed of 30-60 r / min; temperature of 90-100°C; The forming methods include dry pressing and cold isostatic pressing; the dry pressing pressure is 4-6 MPa and the time is 30-60 seconds; the cold isostatic pressing pressure is 180-200 MPa and the time is 10-15 minutes.

9. The preparation method according to claim 1, characterized in that The inert atmosphere is argon or nitrogen.

10. The preparation method according to claim 9, characterized in that The inert atmosphere is argon.

11. A SiC / Ti-Si-C composite material prepared by the preparation method according to any one of claims 1 to 10, characterized in that: The flexural strength of the SiC / Ti-Si-C composite material is 105-220 MPa.

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