A high thermal conductivity sintered silicon carbide ceramic material and a method for making the same

Abstract

The application belongs to the technical field of inorganic nonmetallic materials, and relates to a high-thermal-conductivity spark plasma sintering silicon carbide ceramic material and a preparation method thereof. The application discloses a high-thermal-conductivity spark plasma sintering silicon carbide ceramic material, and raw materials of the high-thermal-conductivity spark plasma sintering silicon carbide ceramic material, according to mass percentage, include 85-98 wt.% of submicron silicon carbide powder, 0.01-2 wt.% of micron silicon carbide powder, 1-10 wt.% of rare earth oxide, 0.5-3 wt.% of magnesium oxide, 0.01-2 wt.% of carbon and 0.5-2 wt.% of dispersant. The application further discloses a preparation method of the high-thermal-conductivity spark plasma sintering silicon carbide ceramic material. The application adds magnesium oxide as a second sintering aid on the basis of a raw material system taking submicron silicon carbide powder as raw material and rare earth oxide as a sintering aid, significantly reduces the eutectic point and viscosity of a liquid phase, can effectively promote the mass transfer efficiency in the sintering process, improves the densification and grain growth efficiency, and thus improves the thermal conductivity of the SiC ceramic.

Description

Technical Field

[0001] This invention belongs to the field of inorganic non-metallic materials technology, and relates to a high thermal conductivity discharge plasma sintered silicon carbide ceramic material and its preparation method. Background Technology

[0002] SiC ceramics possess excellent properties such as lightweight, high strength, high hardness, corrosion resistance, high temperature resistance, and radiation resistance, making them a strategic engineering material with both military and civilian applications. They have wide applications in aerospace, defense, nuclear energy, and many other fields. Due to the strong covalent bond of the Si-C bond, SiC ceramics exhibit extremely high theoretical thermal conductivity. According to Slack's theoretical calculations, the intrinsic thermal conductivity of a perfect SiC single crystal at room temperature reaches as high as 490 W·m. -1 ·K -1 Therefore, SiC ceramics have broad application prospects in fields with high requirements for thermal conductivity, such as high-power chip packaging heat dissipation substrates, electrostatic chuck heaters, and heat exchangers. However, the microstructure of polycrystalline SiC ceramics contains randomly oriented grains, lattice defects within the grains, pores, and residual second phases at grain boundaries, resulting in a thermal conductivity much lower than that of single-crystal SiC. Currently reported room-temperature thermal conductivity of SiC ceramics ranges from 30 to 270 W·m. -1 ·K -1 Domestic and international scholars have conducted extensive research on the preparation of high thermal conductivity SiC ceramics. However, current preparation methods still suffer from problems such as toxic sintering aids, long sintering processes with high energy consumption, and low thermal conductivity of the resulting SiC ceramics. How to prepare high thermal conductivity SiC ceramics that meet application requirements based on non-toxic sintering aids and an efficient and energy-saving sintering process remains a key technical challenge worldwide.

[0003] In existing technologies, SiC ceramics with high thermal conductivity are often obtained by hot-pressing sintering with the assistance of sintering aids and holding at high temperature for a long time. For example, Chinese patent application (publication number: CN104926313A) discloses a method using silicon carbide, graphene, and carbon powder as main raw materials, which is sintered at 1650-2000℃ for 8-12 hours via a silicon infiltration reaction to obtain a thermal conductivity of approximately 120 W·m. -1 ·K -1 While SiC ceramics are produced using a reaction sintering process, the resulting SiC ceramics inevitably contain free silicon and residual carbon, which reduces their high-temperature resistance, corrosion resistance, and oxidation resistance, limiting their reliability under extreme service environments, and also results in poor thermal conductivity. Therefore, researchers have sought to improve this process. For example, Chinese patent application (publication number: CN109592983A) discloses a method using at least two of rare earth oxides CeO2, Y2O3, and Er2O3 as sintering aids, followed by liquid-phase sintering at 1850–2000℃ for 0.5–1.5 hours, to improve thermal conductivity to 150 W·m.-1 ·K -1 However, its raw material system has a slow heating rate during the preparation process, a long preparation cycle, increased production costs, and still poor thermal conductivity. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a high thermal conductivity discharge plasma sintering silicon carbide ceramic material comprising submicron-sized silicon carbide powder and micron-sized silicon carbide powder, with a highly efficient and energy-saving preparation process.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A high thermal conductivity spark plasma sintered silicon carbide ceramic material, wherein the raw materials of the high thermal conductivity spark plasma sintered silicon carbide ceramic material, by mass percentage, include 85-98 wt.% submicron-sized silicon carbide powder, 0.01-2 wt.% micron-sized silicon carbide powder, 1-10 wt.% rare earth oxides, 0.5-3 wt.% magnesium oxide, 0.01-2 wt.% carbon, and 0.5-2 wt.% dispersant.

[0007] This invention adjusts the raw material ratio to achieve a submicron-sized silicon carbide powder content of 85–98 wt.%, aiming to increase the percentage of the main crystalline phase and reduce the content of the second phase, thereby reducing the scattering effect of the second phase on phonons and improving thermal conductivity. Furthermore, magnesium oxide is added to the silicon carbide powder and rare earth oxide system as a second sintering aid to lower the eutectic point and viscosity of the liquid phase; micron-sized silicon carbide is added as a seed crystal, serving as a template during high-temperature sintering to induce rapid SiC grain growth through a dissolution-precipitation mechanism, reducing the number of grain boundaries; carbon is added as a reducing agent to eliminate inherent SiO2 impurities in the SiC raw material, significantly reducing the probability of SiO2 impurities dissolving into the SiC lattice and forming lattice oxygen defects during high-temperature sintering, and also reducing the content of residual liquid phase at grain boundaries. The synergistic effect of these raw materials effectively improves the thermal conductivity of silicon carbide ceramics.

[0008] Preferably, the submicron-sized silicon carbide powder is one of α-SiC and β-SiC; the micron-sized silicon carbide powder is one of α-SiC and β-SiC.

[0009] Preferably, the median particle size D50 of submicron silicon carbide powder is 0.3–0.8 μm; and the D50 of micron silicon carbide is 5–10 μm.

[0010] Preferably, the rare earth oxide is added in an amount of 4-8 wt.%, the magnesium oxide in an amount of 0.8-1.5 wt.%, and the carbon in an amount of 0.3-1 wt.%.

[0011] Preferably, the rare earth oxide is one or more of Y2O3, Yb2O3, Er2O3, Sc2O3, Sm2O3, Lu2O3, Dy2O3, and CeO2.

[0012] Preferably, the carbon includes one or more of inorganic carbon sources, organic carbon sources, and residual carbon from pyrolysis.

[0013] Further preferably, the inorganic carbon source includes one or more of carbon black and graphite; the organic carbon source includes one or more of phenolic resin, fructose, and glucose.

[0014] Preferably, the dispersant is one or more of tetramethylammonium hydroxide, polyethyleneimine, and polyacrylic acid.

[0015] Preferably, the thermal conductivity of the high thermal conductivity discharge plasma sintered silicon carbide ceramic material can reach 240 W·m. -1 ·K -1 .

[0016] This invention also discloses a method for preparing a high thermal conductivity discharge plasma sintered silicon carbide ceramic material. The preparation method includes: mixing all raw materials with a solvent, ball milling to form a slurry, drying, crushing, sieving, pre-pressing, debinding, and discharge plasma sintering to obtain a high thermal conductivity discharge plasma sintered silicon carbide ceramic material.

[0017] Preferably, the solvent is one or more of anhydrous ethanol, isopropanol, and water.

[0018] More preferably, the mass ratio of the raw material to the solvent is 1:(1 to 1.5).

[0019] Preferably, the pressure during the pre-compression molding process is 5 to 15 MPa.

[0020] Preferably, the adhesive removal process is carried out in a graphite resistance furnace at a temperature of 800–1100°C for 1–4 hours.

[0021] Preferably, the heating rate of the discharge plasma sintering process is 100-150℃ / min, the sintering temperature is 2010-2080℃, the sintering holding time is 0.5-1h, the sintering pressure is 30-50MPa, and the sintering atmosphere is argon or nitrogen.

[0022] During spark plasma sintering, excessively high temperatures can lead to rapid and massive evaporation of the liquid phase, potentially leaving behind numerous pores. On the other hand, it can cause abnormal grain growth, resulting in a large number of defects within the grains. Conversely, excessively low temperatures can prevent the sample grains from growing sufficiently, and the low evaporation of the liquid phase at the grain boundaries can lead to a high content of residual phase at the grain boundaries. Both of these conditions can cause phonon scattering and reduce thermal conductivity.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. Based on the traditional raw material system using submicron silicon carbide powder as raw material and rare earth oxides as sintering aids, this invention adds magnesium oxide as a second sintering aid, which significantly reduces the eutectic point and viscosity of the liquid phase, effectively promotes the mass transfer efficiency during sintering, improves densification and grain growth efficiency, and thus enhances the thermal conductivity of SiC ceramics.

[0025] 2. In this invention, micron-sized silicon carbide is added to the raw materials as seed crystals. During the high-temperature sintering process, it can serve as a seed crystal template, inducing SiC grains to grow rapidly through a dissolution-precipitation mechanism, reducing the number of grain boundaries, and thus further improving the thermal conductivity of SiC ceramics.

[0026] 3. The present invention adds carbon as a reducing agent to the raw materials, which effectively eliminates the inherent SiO2 impurities in the SiC raw materials and significantly reduces the probability of SiO2 impurities dissolving into the SiC lattice and forming lattice oxygen defects during high-temperature sintering, thereby improving the thermal conductivity of SiC ceramics.

[0027] 4. In the preparation process of the high thermal conductivity discharge plasma sintered silicon carbide ceramic material of the present invention, the heating rate is fast and the holding time is short, which has the advantages of high efficiency and energy saving, and significantly reduces the production and manufacturing cost.

[0028] 5. The high thermal conductivity discharge plasma sintered silicon carbide ceramic material obtained by the present invention has high thermal conductivity, which can meet the application requirements of high power chip packaging heat dissipation substrate, electrostatic chuck heater, heat exchanger and other occasions with high thermal conductivity requirements. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process flow for preparing high thermal conductivity discharge plasma sintered silicon carbide ceramics according to the present invention.

[0030] Figure 2 This is a microscopic schematic diagram of the high thermal conductivity discharge plasma sintered silicon carbide ceramic material prepared in Example 1 of the present invention.

[0031] Figure 3 This is a microscopic schematic diagram of the silicon carbide ceramic material prepared in Comparative Example 1 of the present invention.

[0032] Figure 4 This is a microscopic schematic diagram of the silicon carbide ceramic material prepared in Comparative Example 2 of the present invention.

[0033] Figure 5 This is a microscopic schematic diagram of the silicon carbide ceramic material prepared in Comparative Example 3 of the present invention.

[0034] Figure 6 This is a microscopic schematic diagram of the silicon carbide ceramic material prepared in Comparative Example 4 of the present invention.

[0035] Figure 7 This is a microscopic schematic diagram of the silicon carbide ceramic material prepared in Comparative Example 5 of the present invention.

[0036] Figure 8 This is a microscopic schematic diagram of the silicon carbide ceramic material prepared in Comparative Example 6 of the present invention. Detailed Implementation

[0037] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0038] Example 1

[0039] Weigh the raw materials, which, by mass percentage, include: 90.1 wt.% submicron grade (D 50 =0.5μm)β-SiC, 1.0wt.% micron-scale (D 50 =5μm)α-SiC, 5.4wt.%Y2O3, 2.0wt.%MgO, 1.0wt.%carbon black, 0.5wt.%polyacrylamide; then mixed with anhydrous ethanol solvent at a solid-liquid mass ratio of 1:1.2, and ball-milled for 6 hours to form a slurry. The slurry was then vacuum-dried at 60℃ for 2 hours in a rotary evaporator, crushed, and sieved through a 100-mesh sieve. The powder was placed in a mold and pre-pressed under 8MPa pressure, then placed in a graphite resistance furnace and debinded at 1000℃ for 1 hour under normal pressure and vacuum conditions. Finally, it was subjected to spark plasma sintering under an Ar atmosphere at a heating rate of 150℃·min. -1 The sintering temperature was 2050℃, the holding time was 1 hour, and the pressure was 30MPa.

[0040] Preparation flow chart as follows Figure 1 As shown.

[0041] The microstructure of the high thermal conductivity spark plasma sintered silicon carbide ceramic material is as follows: Figure 2 As shown; the density, as measured by the instrument, is 3.21 g·cm³. -3 The density is 97.9%; the thermal diffusivity is 111.61 mm. 2 ·s -1 Specific heat is 0.67 J·g -1 ·K -1 Thermal conductivity is 240 W·m -1 ·K -1 Specific performance details are shown in Table 1.

[0042] Example 2

[0043] Weigh the raw materials, which, by mass percentage, include: 93.3 wt.% submicron grade (D 50 =0.6μm)β-SiC, 1.5wt.% micron-scale (D 50 =10μm)β-SiC, 1.7wt.%Sc2O3, 2.0wt.%MgO, 1.0wt.%carbon black, 0.5wt.%polyethyleneimine; then mixed with anhydrous ethanol solvent at a solid-liquid mass ratio of 1:1, and ball-milled for 8 hours to form a slurry. The slurry was then placed in a rotary evaporator and vacuum-dried at 60℃ for 2 hours, then crushed and sieved through a 160-mesh sieve. The powder was placed in a mold and pre-pressed under 8MPa pressure, then placed in a graphite resistance furnace and debinded at 900℃ for 2 hours under normal pressure and vacuum conditions. Finally, it was subjected to spark plasma sintering under N2 atmosphere at a heating rate of 150℃·min. -1 The sintering temperature was 2040℃, the holding time was 1 hour, and the pressure was 50MPa.

[0044] The properties of the high thermal conductivity spark plasma sintered silicon carbide ceramic material are shown in Table 1.

[0045] Example 3

[0046] Weigh the raw materials, which, by mass percentage, include: 92.2 wt.% submicron grade (D 50 =0.3μm)α-SiC, 1.0wt.% micron-scale (D 50 =5μm)α-SiC, 4.7wt.% Lu2O3, 0.9wt.% MgO, 0.7wt.% graphite, and 0.5wt.% tetramethylammonium hydroxide; then mixed with an aqueous solvent at a solid-liquid mass ratio of 1:1.5, and ball-milled for 6 hours to form a slurry. The slurry was then vacuum-dried at 80℃ for 2 hours in a rotary evaporator, crushed, and sieved through a 200-mesh sieve. The powder was placed in a mold and pre-pressed under 8MPa pressure, then placed in a graphite resistance furnace and debinded at 1000℃ for 1 hour under normal pressure and vacuum conditions. Finally, it was subjected to spark plasma sintering under an Ar atmosphere at a heating rate of 100℃·min. -1 The sintering temperature was 2050℃, the holding time was 1 hour, and the pressure was 20MPa.

[0047] The properties of the high thermal conductivity spark plasma sintered silicon carbide ceramic material are shown in Table 1.

[0048] Example 4

[0049] Compared to Example 1, the difference lies in the raw materials, which, by mass percentage, comprise: 93.3 wt.% submicron-sized (D) 50 =0.6μm)β-SiC, 0.5wt.% micron-scale (D 50=10μm)α-SiC, 4.2wt.%Sm2O3, 0.5wt.%MgO, 1.0wt.%carbon black, 0.5wt.%polyacrylamide.

[0050] The properties of the high thermal conductivity spark plasma sintered silicon carbide ceramic material are shown in Table 1.

[0051] Example 5

[0052] Compared to Example 1, the difference lies in the raw materials, which, by mass percentage, comprise: 88.2 wt.% submicron-sized (D) 50 =0.5μm)β-SiC, 0.5wt.% micron-scale (D 50 =6μm)α-SiC, 9.1wt.%Yb2O3, 0.9wt.%MgO, 1.0wt.%Graphite, 0.3wt.%Polyethyleneimine.

[0053] The properties of the high thermal conductivity spark plasma sintered silicon carbide ceramic material are shown in Table 1.

[0054] Example 6

[0055] Compared to Example 1, the difference lies in the raw materials, which, by mass percentage, comprise: 89.8 wt.% submicron-sized (D) 50 =0.5μm)β-SiC, 0.6wt.% micron-scale (D 50 =5μm)α-SiC, 5.7wt.%Er2O3, 1.9wt.%MgO, 1.5wt.%carbon black, 0.5wt.%polyethyleneimine.

[0056] The properties of the high thermal conductivity spark plasma sintered silicon carbide ceramic material are shown in Table 1.

[0057] Example 7

[0058] Compared to Example 1, the difference lies in the raw materials and sintering temperature. The raw materials, by mass percentage, include: 88.1 wt.% submicron-sized (D) 50 =0.5μm)β-SiC, 0.5wt.% micron-scale (D 50 =10μm) α-SiC, 8.1wt.% Dy2O3, 1.8wt.% MgO, 1.0wt.% graphite, and 0.5wt.% polyacrylamide. After mixing, drying, sieving, pre-pressing, and debinding, the mixture was subjected to spark plasma sintering under an Ar atmosphere at a heating rate of 150℃·min. -1 The sintering temperature was 2010℃, the holding time was 1 hour, and the pressure was 30MPa.

[0059] The properties of the high thermal conductivity spark plasma sintered silicon carbide ceramic material are shown in Table 1.

[0060] Example 8

[0061] Compared to Example 1, the difference lies in the raw materials and sintering temperature, comprising, by mass percentage: 92.9 wt.% submicron-sized (D 50 =0.3μm)β-SiC, 1.0wt.% micron-scale (D 50 =8μm) α-SiC, 2.1wt.% CeO2, 2.0wt.% MgO, 1.5wt.% carbon black, 0.5wt.% polyethyleneimine. After mixing, drying, sieving, pre-pressing, and debinding, the mixture was subjected to spark plasma sintering under an Ar atmosphere at a heating rate of 150℃·min. -1 The sintering temperature was 2010℃, the holding time was 1 hour, and the pressure was 30MPa.

[0062] The properties of the high thermal conductivity spark plasma sintered silicon carbide ceramic material are shown in Table 1.

[0063] Comparative Example 1

[0064] Compared with Example 1, the difference lies in changing the sintering temperature. After debinding, spark plasma sintering is performed in an Ar atmosphere, with a heating rate of 150°C·min. -1 The sintering temperature was 1950℃, the holding time was 1 hour, and the pressure was 30MPa.

[0065] The microstructure of the prepared silicon carbide ceramic material is as follows Figure 3 As shown; performance data is shown in Table 1.

[0066] Comparative Example 2

[0067] Compared to Example 1, the difference lies in the absence of micron-sized silicon carbide and carbon in the raw materials, which, by mass percentage, comprise 92.1 wt.% submicron-sized (D) silicon carbide. 50 =0.5μm)β-SiC, 5.4wt.%Y2O3, 2.0wt.%MgO, 0.5wt.%polyacrylamide.

[0068] The microstructure of the prepared silicon carbide ceramic material is as follows Figure 4 As shown; performance data is shown in Table 1.

[0069] Comparative Example 3

[0070] Compared to Example 1, the difference lies in the absence of micron-sized silicon carbide in the raw materials, which, by mass percentage, comprise 91.1 wt.% submicron-sized (D) silicon carbide. 50=0.5μm)β-SiC, 5.4wt.%Y2O3, 2.0wt.%MgO, 1.0wt.%carbon black, 0.5wt.%polyacrylamide.

[0071] The microstructure of the prepared silicon carbide ceramic material is as follows Figure 5 As shown; performance data is shown in Table 1.

[0072] Comparative Example 4

[0073] Compared to Example 1, the difference is that no carbon is added to the raw materials, which, by mass percentage, comprise: 91.1 wt.% submicron-sized (D) 50 =0.5μm)β-SiC, 1.0wt.% micron-scale (D 50 =5μm)α-SiC, 5.4wt.%Y2O3, 2.0wt.%MgO, 0.5wt.%polyacrylamide.

[0074] The microstructure of the prepared silicon carbide ceramic material is as follows Figure 6 As shown; performance data is shown in Table 1.

[0075] Comparative Example 5

[0076] The difference compared to Example 1 is that the heating rate is 10°C·min. -1 .

[0077] The properties of the obtained spark plasma sintered silicon carbide ceramic materials are shown in Table 1.

[0078] Comparative Example 6

[0079] Compared to Example 1, the difference lies in the raw materials, which, by mass percentage, comprise: 83.4 wt.% submicron-sized (D) 50 =0.5μm)β-SiC, 3.0wt.% micron-scale (D 50 =5μm)α-SiC, 9.4wt.%Y2O3, 2.0wt.%MgO, 1.0wt.%carbon black, 1.2wt.%polyacrylamide.

[0080] The properties of the obtained spark plasma sintered silicon carbide ceramic materials are shown in Table 1.

[0081] Table 1. Performance data of the obtained spark plasma sintered silicon carbide ceramic materials

[0082]

[0083] Examples 1-8 are high thermal conductivity spark plasma sintered silicon carbide ceramic materials obtained from raw materials and preparation methods within the scope of this invention. Figure 2As shown in the table above, the high thermal conductivity spark plasma sintered silicon carbide ceramic material of this invention exhibits high thermal conductivity, and its microstructure reveals large grain size and clean grain boundaries, which is beneficial for phonon heat transfer. In Comparative Example 1, the sintering temperature was lower, resulting in insufficient grain growth and a higher residual amount of liquid phase at the grain boundaries due to insufficient evaporation. Figure 3 As shown, the small grain size and abundant residual liquid phase at grain boundaries result in significant phonon scattering effects and an inability to achieve high thermal conductivity. In Comparative Example 2, the absence of carbon and micron-sized silicon carbide prevents the effective use of micron-sized silicon carbide as a seed template and the absence of carbon as a reducing agent, leading to small grain size and abundant residual phase at grain boundaries. Figure 4 As shown, the sample has a small grain size and a large amount of residual grain boundary phase, resulting in a significant phonon scattering effect and an inability to achieve high thermal conductivity. In Comparative Example 3, the absence of micron-sized silicon carbide prevents it from functioning as a seed template, leading to a smaller grain size. Figure 5 As shown, the sample has a small grain size, resulting in a significant phonon scattering effect and an inability to achieve high thermal conductivity; in Comparative Example 4, no carbon was added, so carbon could not function as a reducing agent, leading to a large amount of residual phase at grain boundaries, such as... Figure 6 As shown, the sample has a large amount of residual grain boundary phase at the grain boundaries, resulting in a significant phonon scattering effect and making it impossible to obtain high thermal conductivity; in Comparative Example 5, the heating rate is slow (10℃·min). -1 This leads to a large amount of liquid phase evaporation during the heating process, slow grain growth, and the inability to completely eliminate porosity, such as... Figure 7 As shown, the sample has a small grain size and many pores, resulting in a significant phonon scattering effect and an inability to achieve high thermal conductivity. In Comparative Example 6, the submicron-sized silicon carbide content is less than 85%, and the micron-sized silicon carbide content is more than 2%, leading to an excessive number of seed crystals that mutually inhibit growth and consequently reduce the grain size. Figure 8 As shown, the sample grain size is small, resulting in a significant phonon scattering effect and making it impossible to obtain high thermal conductivity.

[0084] In summary, this invention, based on the traditional raw material system using submicron-sized silicon carbide powder as raw material and rare earth oxides as sintering aids, adds magnesium oxide as a second sintering aid, significantly reducing the eutectic point and viscosity of the liquid phase, effectively promoting mass transfer efficiency during sintering, and improving densification and grain growth efficiency. The addition of micron-sized silicon carbide as a seed crystal acts as a template during high-temperature sintering, inducing rapid SiC grain growth through a dissolution-precipitation mechanism and reducing the number of grain boundaries. The addition of carbon as a reducing agent effectively eliminates inherent SiO2 impurities in the SiC raw material, significantly reducing the probability of SiO2 impurities dissolving into the SiC lattice and forming lattice oxygen defects during high-temperature sintering, and also reducing the residual liquid phase content at grain boundaries. Furthermore, the preparation process features rapid heating and short holding time, offering high efficiency and energy saving, significantly reducing production costs. The resulting high thermal conductivity discharge plasma sintered silicon carbide ceramic material possesses high thermal conductivity, meeting the application requirements of high-power chip packaging heat dissipation substrates, electrostatic chuck heaters, heat exchangers, and other applications with high thermal conductivity requirements.

[0085] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for preparing a high thermal conductivity spark plasma sintered silicon carbide ceramic material, characterized in that, The process includes the following steps: After mixing all raw materials with solvent and ball milling to form a slurry, the slurry is dried, crushed, sieved, pre-pressed, debinded, and then sintered by spark plasma to obtain a spark plasma sintered silicon carbide ceramic material with high thermal conductivity. The raw materials, by mass percentage, consist of: 85-98 wt.% submicron-sized silicon carbide powder, 0.01-2 wt.% micron-sized silicon carbide powder, 1-10 wt.% rare earth oxides, 0.5-3 wt.% magnesium oxide, 0.01-2 wt.% carbon, and 0.5-2 wt.% dispersant. The rare earth oxide is one or more of Y2O3, Yb2O3, Er2O3, Sc2O3, Sm2O3, Lu2O3, Dy2O3, and CeO2; The carbon includes one or more of inorganic carbon sources and organic carbon sources; The adhesive removal process is carried out in a graphite resistance furnace under vacuum conditions at a temperature of 800~1100℃ for 1~4 hours. The heating rate of the discharge plasma sintering process is 100~150℃ / min, the sintering temperature is 2010~2080℃, the sintering holding time is 0.5~1h, the sintering pressure is 30~50MPa, and the sintering atmosphere is argon or nitrogen.

2. The preparation method according to claim 1, characterized in that, The mass ratio of all raw materials and solvents is 1:(1~1.5).

3. The preparation method according to claim 1, characterized in that, The submicron-sized silicon carbide powder is one of α-SiC and β-SiC; the micron-sized silicon carbide powder is one of α-SiC and β-SiC.

4. The preparation method according to claim 1, characterized in that, The median particle size D50 of the submicron-sized silicon carbide powder is 0.3~0.8μm; the D50 of the micron-sized silicon carbide is 5~10μm.

5. The preparation method according to claim 1, characterized in that, The inorganic carbon source includes one or more of carbon black and graphite; the organic carbon source includes one or more of phenolic resin, fructose, and glucose.

6. The preparation method according to claim 1, characterized in that, The pressure during the pre-compression molding process is 5~15MPa.

7. The preparation method according to claim 1, characterized in that, The thermal conductivity of the high thermal conductivity spark plasma sintered silicon carbide ceramic material reaches 240 W·m. -1 ·K -1 .

8. A high thermal conductivity spark plasma sintered silicon carbide ceramic material, characterized in that, It is prepared by the method for preparing high thermal conductivity spark plasma sintered silicon carbide ceramic materials as described in any one of claims 1 to 7.

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