High-strength high-thermal-conductivity silicon carbide support member and method for producing the same

Abstract

This invention specifically relates to a high-strength, high-thermal-conductivity silicon carbide support component and its preparation method. The technical solution is as follows: 10-20 wt% silicon carbide particles with a particle size of 2-1 mm, 25-35 wt% silicon carbide particles with a particle size of 1-0.5 mm, 10-20 wt% silicon carbide particles with a particle size ≤0.5 mm, 30-40 wt% silicon carbide fine powder with a particle size ≤0.088 mm, 1-3 wt% ammonium metavanadate, 1-2 wt% sintering aid, and 1-2 wt% binder are added to a mixing mill. Silicon carbide particles with particle sizes of 2-1 mm, 1-0.5 mm, and ≤0.5 mm are then added, along with anhydrous ethanol. The mixture is then mixed and milled. Silicon carbide fine powder, ammonium metavanadate, sintering aid, and binder are added sequentially. The mixture is then subjected to pressurization and depressurization processes. Finally, it undergoes two heat treatments under an argon or nitrogen atmosphere to obtain a high-strength, high-thermal-conductivity silicon carbide support component. The products manufactured by this invention have high high-temperature flexural strength, high thermal shock stability, high thermal conductivity, and good oxidation resistance.

Description

Technical Field

[0001] This invention belongs to the technical field of silicon carbide support components. Specifically, it relates to a high-strength, high-thermal-conductivity silicon carbide support component and its preparation method. Background Technology

[0002] Silicon carbide materials have advantages such as high mechanical strength, strong resistance to acid and alkali corrosion, high thermal conductivity, good chemical stability, and low coefficient of thermal expansion. Therefore, silicon carbide is widely used as a supporting component in high-temperature kiln furniture, combustion chamber lining, heat treatment equipment and other fields.

[0003] Currently, the main methods for preparing silicon carbide support components include solid-state sintering, liquid-state sintering, reaction sintering, and recrystallization sintering. Silicon carbide support components prepared using different sintering processes exhibit significant performance differences, which has attracted the attention of those skilled in the art.

[0004] The patented technology, "A Low-Temperature Sintered Pure Porous Silicon Carbide Ceramic Support and Its Preparation Method (CN202410176849.8)," uses silicon carbide particles and silicon carbide precursors as raw materials. Although the prepared pure silicon carbide support has a low sintering temperature and high thermal conductivity, pure silicon carbide is prone to oxidation at high temperatures, which leads to a reduction in its service life.

[0005] The patented technology, “A silicon carbide ceramic film support and its preparation method (CN102389719A),” employs recrystallization sintering technology, utilizing the sublimation and recondensation of small-sized silicon carbide particles at high temperatures above 2200℃ to achieve sintering. However, it has drawbacks such as high sintering temperature and complex sintering process.

[0006] The patented technology, "A method for preparing a low-temperature sintered acid and alkali resistant porous silicon carbide ceramic support (CN201710656733.4)," uses an extrusion molding method and utilizes various minerals such as Suzhou clay, calcined talc, chalk, and fluorite as sintering aids to prepare the silicon carbide support. Although the preparation process is simple and the sintering temperature is low, excessive liquid phase can lead to problems such as low thermal conductivity and low high-temperature flexural strength of the silicon carbide support.

[0007] The patented technology, "A method for preparing porous silicon carbide supports at low temperature (CN201610442510.3)," uses silicon carbide fine powder as the main raw material and introduces activated carbon powder as a pore-forming agent to prepare silicon carbide supports with good gas permeability and chemical stability, but still has problems with insufficient thermal conductivity and low thermal shock stability.

[0008] In summary, existing silicon carbide support components are limited by their composition and preparation methods, resulting in problems such as high sintering temperature, low high-temperature flexural strength, low thermal shock stability, low thermal conductivity, and low oxidation resistance. Summary of the Invention

[0009] The present invention aims to overcome the shortcomings of the existing technology and provides a method for preparing high-strength, high-thermal-conductivity silicon carbide support components. The high-strength, high-thermal-conductivity silicon carbide support components prepared by this method have low sintering temperature, high high-temperature flexural strength, high thermal shock stability, high thermal conductivity, and good oxidation resistance.

[0010] To achieve the above objectives, the specific steps of the technical solution adopted by the present invention are as follows:

[0011] Step 1: Prepare the following ingredients: 10-20 wt% silicon carbide particles with a particle size of 1-2 mm, 25-35 wt% silicon carbide particles with a particle size of 0.5-1 mm, 10-20 wt% silicon carbide particles with a particle size of ≤0.5 mm, 30-40 wt% silicon carbide fine powder with a particle size of ≤0.088 mm, 1-3 wt% ammonium metavanadate, 1-2 wt% sintering aid, and 1-2 wt% binder.

[0012] Step 2: Following the batching method described in Step 1, first add the silicon carbide particles with a particle size of 1-2 mm, silicon carbide particles with a particle size of 0.5-1 mm, and silicon carbide particles with a particle size of ≤0.5 mm to a mixing mill, then add 3-5 wt% of anhydrous ethanol from the batching method, and mix for 8-12 minutes. Then, add the silicon carbide fine powder, the ammonium metavanadate, the sintering aid, and the binder in sequence, and mix for 10-15 minutes to obtain a mixture.

[0013] Step 3: Place the mixture in a mold, seal it, and move it to the pressure chamber of an isostatic press. First, perform a pressurization process, and then a depressurization process to obtain a silicon carbide support component green blank.

[0014] Step 4: Under an argon or nitrogen atmosphere, the silicon carbide support component green blank is first heat-treated at 800-1000℃ for 1-3 hours, and then heat-treated at 1300-1500℃ for 2-4 hours to obtain a high-strength, high-thermal-conductivity silicon carbide support component.

[0015] The chemical composition of the silicon carbide particles is: SiC content ≥ 97.0 wt%, Fe2O3 content ≤ 0.5 wt%; the silicon carbide fine powder has the same chemical composition as the silicon carbide particles.

[0016] The ammonium metavanadate contains ≥99.0 wt% NH4VO3.

[0017] The sintering aid is a mixture of yttrium oxide and lanthanum oxide; wherein the molar ratio of yttrium oxide to lanthanum oxide is 1 to 1.2:1.

[0018] The binder is bisphenol A type epoxy resin or liquid aluminum dihydrogen phosphate; wherein: the purity of the bisphenol A type epoxy resin is ≥98.0wt%, and the FeO content of the liquid aluminum dihydrogen phosphate is ≤0.02wt%.

[0019] The pressurization process is as follows: pressurize sequentially at a rate of 0.2–4.0 MPa / s to 25–40 MPa, at a rate of 0.2–6.0 MPa / s to 50–70 MPa, at a rate of 0.2–8.0 MPa / s to 80–100 MPa, at a rate of 0.2–10.0 MPa / s to 110–130 MPa, and at a rate of 0.5–8.0 MPa / s to 140–170 MPa; hold the pressure for 1–5 minutes.

[0020] The pressure reduction process is as follows: the pressure is reduced sequentially at a rate of 0.2–5.0 MPa / s to 110–130 MPa, at a rate of 0.2–10.0 MPa / s to 80–100 MPa, at a rate of 0.2–8.0 MPa / s to 50–70 MPa, at a rate of 0.2–6.0 MPa / s to 20–40 MPa, and at a rate of 0.2–4.0 MPa / s to 2 MPa; then unloaded to atmospheric pressure.

[0021] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0022] (1) Based on strictly limiting the particle size distribution of silicon carbide raw materials, this invention utilizes the particle stacking and the decomposition of ammonium metavanadate (2NH4VO3=V2O5+H2O+2NH3) during heat treatment to form a suitable amount of micropores inside the material. By utilizing the high thermal conductivity and low thermal expansion coefficient of silicon carbide, the prepared high-strength and high-thermal-conductivity silicon carbide support component has high thermal shock stability.

[0023] (2) In this invention, vanadium pentoxide formed by the decomposition of ammonium metavanadate during heat treatment reacts with impurities in silicon carbide raw materials to form a vanadate liquid phase, which then encapsulates silicon carbide particles in situ, avoiding oxidation of silicon carbide particles during high-temperature use and maintaining their high thermal conductivity. The high-strength, high-thermal-conductivity silicon carbide support component prepared has good oxidation resistance and high thermal conductivity.

[0024] (3) The mixture of yttrium oxide and lanthanum oxide used in this invention not only lowers the sintering temperature of silicon carbide support components as a sintering aid, but also increases the viscosity of vanadate and silicate liquid phases at high temperatures, thereby increasing the bonding strength between raw material particles and significantly improving the high-temperature flexural strength of silicon carbide support components. The high-strength, high-thermal-conductivity silicon carbide support components prepared have low sintering temperature and high high-temperature flexural strength.

[0025] The high-strength, high-thermal-conductivity silicon carbide support component prepared by this invention was tested and found to have a bulk density of 2.92–3.10 g / cm³. 3 Thermal conductivity ≥100 W / (m·K); High-temperature flexural strength 15–20 MPa (1200℃, 0.5h); Thermal shock resistance ≥20 cycles (1100℃, air cooling); Oxide layer thickness ≤0.20 mm (1400℃, 2h); Coefficient of thermal expansion (20–1000℃) (4.5–5.0) × 10⁻⁶ -6 / ℃.

[0026] Therefore, the high-strength, high-thermal-conductivity silicon carbide support component prepared by this invention has a low sintering temperature, high high-temperature flexural strength, high thermal shock stability, high thermal conductivity, and good oxidation resistance. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, but this is not intended to limit the scope of protection thereof.

[0028] A high-strength, high-thermal-conductivity silicon carbide support component and its preparation method. The preparation method described in this specific embodiment is as follows:

[0029] Step 1: Prepare the following ingredients: 10-20 wt% silicon carbide particles with a particle size of 1-2 mm, 25-35 wt% silicon carbide particles with a particle size of 0.5-1 mm, 10-20 wt% silicon carbide particles with a particle size of ≤0.5 mm, 30-40 wt% silicon carbide fine powder with a particle size of ≤0.088 mm, 1-3 wt% ammonium metavanadate, 1-2 wt% sintering aid, and 1-2 wt% binder.

[0030] Step 2: Following the batching method described in Step 1, first add the silicon carbide particles with a particle size of 1-2 mm, silicon carbide particles with a particle size of 0.5-1 mm, and silicon carbide particles with a particle size of ≤0.5 mm to a mixing mill, then add 3-5 wt% of anhydrous ethanol from the batching method, and mix for 8-12 minutes. Then, add the silicon carbide fine powder, the ammonium metavanadate, the sintering aid, and the binder in sequence, and mix for 10-15 minutes to obtain a mixture.

[0031] Step 3: Place the mixture in a mold, seal it, and move it to the pressure chamber of an isostatic press. First, perform a pressurization process, and then a depressurization process to obtain a silicon carbide support component green blank.

[0032] Step 4: Under an argon or nitrogen atmosphere, the silicon carbide support component green blank is first heat-treated at 800-1000℃ for 1-3 hours, and then heat-treated at 1300-1500℃ for 2-4 hours to obtain a high-strength, high-thermal-conductivity silicon carbide support component.

[0033] The sintering aid is a mixture of yttrium oxide and lanthanum oxide; wherein the molar ratio of yttrium oxide to lanthanum oxide is 1 to 1.2:1.

[0034] The binder is bisphenol A type epoxy resin or liquid aluminum dihydrogen phosphate; wherein: the purity of the bisphenol A type epoxy resin is ≥98.0wt%, and the FeO content of the liquid aluminum dihydrogen phosphate is ≤0.02wt%.

[0035] The pressurization process is as follows: pressurize sequentially at a rate of 0.2–4.0 MPa / s to 25–40 MPa, at a rate of 0.2–6.0 MPa / s to 50–70 MPa, at a rate of 0.2–8.0 MPa / s to 80–100 MPa, at a rate of 0.2–10.0 MPa / s to 110–130 MPa, and at a rate of 0.5–8.0 MPa / s to 140–170 MPa; hold the pressure for 1–5 minutes.

[0036] The pressure reduction process is as follows: the pressure is reduced sequentially at a rate of 0.2–5.0 MPa / s to 110–130 MPa, at a rate of 0.2–10.0 MPa / s to 80–100 MPa, at a rate of 0.2–8.0 MPa / s to 50–70 MPa, at a rate of 0.2–6.0 MPa / s to 20–40 MPa, and at a rate of 0.2–4.0 MPa / s to 2 MPa; then unloaded to atmospheric pressure.

[0037] In this specific implementation:

[0038] The chemical composition of the silicon carbide particles is: SiC content ≥ 97.0 wt%, Fe2O3 content ≤ 0.5 wt%; the silicon carbide fine powder has the same chemical composition as the silicon carbide particles.

[0039] The ammonium metavanadate contains ≥99.0 wt% NH4VO3.

[0040] The details will not be repeated in the examples.

[0041] Example 1

[0042] A high-strength, high-thermal-conductivity silicon carbide support component and its preparation method. The preparation method described in this embodiment is as follows:

[0043] Step 1: Prepare the following ingredients: 10 wt% silicon carbide particles with a particle size of 1-2 mm, 35 wt% silicon carbide particles with a particle size of 0.5-1 mm, 20 wt% silicon carbide particles with a particle size of ≤0.5 mm, 30 wt% silicon carbide fine powder with a particle size of ≤0.088 mm, 1 wt% ammonium metavanadate, 2 wt% sintering aid, and 2 wt% binder.

[0044] Step 2: Following the batching method described in Step 1, first add the silicon carbide particles with a particle size of 1-2 mm, silicon carbide particles with a particle size of 0.5-1 mm, and silicon carbide particles with a particle size of ≤0.5 mm to the mixer, then add 3 wt% of anhydrous ethanol from the batching method, and mix for 8 minutes. Then, add the silicon carbide fine powder, the ammonium metavanadate, the sintering aid, and the binder in sequence, and mix for 10 minutes to obtain the mixture.

[0045] Step 3: Place the mixture in a mold, seal it, and move it to the pressure chamber of an isostatic press. First, perform a pressurization process, and then a depressurization process to obtain a silicon carbide support component green blank.

[0046] Step 4: Under an argon atmosphere, the silicon carbide support component green blank is first heat-treated at 800°C for 1 hour, and then heat-treated at 1300°C for 2 hours to obtain a high-strength, high-thermal-conductivity silicon carbide support component.

[0047] In this embodiment:

[0048] The sintering aid is a mixture of yttrium oxide and lanthanum oxide, wherein the molar ratio of yttrium oxide to lanthanum oxide is 1:1.

[0049] The binder is a bisphenol A type epoxy resin with a purity ≥98.0wt%.

[0050] The pressurization process is as follows: the pressure is increased sequentially at a rate of 0.2 MPa / s to 25 MPa, then at a rate of 0.2 MPa / s to 50 MPa, then at a rate of 0.2 MPa / s to 80 MPa, then at a rate of 0.2 MPa / s to 110 MPa; then at a rate of 0.5 MPa / s to 140 MPa, and held at that pressure for 1 minute.

[0051] The pressure reduction process is as follows: the pressure is reduced sequentially at a rate of 0.2 MPa / s to 130 MPa, then at a rate of 0.2 MPa / s to 100 MPa, then at a rate of 0.2 MPa / s to 70 MPa, then at a rate of 0.2 MPa / s to 40 MPa, and finally at a rate of 0.2 MPa / s to 2 MPa; then unloaded to atmospheric pressure.

[0052] The high-strength, high-thermal-conductivity silicon carbide support component prepared in this embodiment was tested and found to have a bulk density of 2.92 g / cm³. 3Thermal conductivity: 102.1 W / (m·K); High-temperature flexural strength: 19.8 MPa (1200℃, 0.5h); Thermal shock resistance: 25 cycles (1100℃, air cooling); Oxide layer thickness: 0.20 mm (1400℃, 2h); Coefficient of thermal expansion (20~1000℃): 4.5×10⁻⁶ -6 / ℃.

[0053] Example 2

[0054] A high-strength, high-thermal-conductivity silicon carbide support component and its preparation method. The preparation method described in this embodiment is as follows:

[0055] Step 1: Prepare the following ingredients: 15 wt% silicon carbide particles with a particle size of 1-2 mm, 30 wt% silicon carbide particles with a particle size of 0.5-1 mm, 17 wt% silicon carbide particles with a particle size of ≤0.5 mm, 32 wt% silicon carbide fine powder with a particle size of ≤0.088 mm, 2 wt% ammonium metavanadate, 2 wt% sintering aid, and 2 wt% binder.

[0056] Step 2: Following the batching method described in Step 1, first add the silicon carbide particles with a particle size of 1-2 mm, silicon carbide particles with a particle size of 0.5-1 mm, and silicon carbide particles with a particle size of ≤0.5 mm to the mixer, then add 4 wt% of anhydrous ethanol from the batching method, and mix for 9 minutes. Then, add the silicon carbide fine powder, the ammonium metavanadate, the sintering aid, and the binder in sequence, and mix for 12 minutes to obtain the mixture.

[0057] Step 3: Place the mixture in a mold, seal it, and move it to the pressure chamber of an isostatic press. First, perform a pressurization process, and then a depressurization process to obtain a silicon carbide support component green blank.

[0058] Step 4: Under an argon atmosphere, the silicon carbide support component green blank is first heat-treated at 900°C for 2 hours, and then heat-treated at 1400°C for 3 hours to obtain a high-strength, high-thermal-conductivity silicon carbide support component.

[0059] In this embodiment:

[0060] The sintering aid is a mixture of yttrium oxide and lanthanum oxide; wherein the molar ratio of yttrium oxide to lanthanum oxide is 1.1:1.

[0061] The binder is a bisphenol A type epoxy resin with a purity ≥98.0wt%.

[0062] The pressurization process is as follows: the pressure is increased sequentially at a rate of 1.0 MPa / s to 30 MPa, at a rate of 2.0 MPa / s to 55 MPa, at a rate of 2.5 MPa / s to 90 MPa, and at a rate of 3.0 MPa / s to 120 MPa; then the pressure is increased to 150 MPa at a rate of 2.5 MPa / s, and held for 2 minutes.

[0063] The pressure reduction process is as follows: the pressure is reduced sequentially at a rate of 2.0 MPa / s to 120 MPa, at a rate of 3.0 MPa / s to 90 MPa, at a rate of 2.0 MPa / s to 60 MPa, at a rate of 2.0 MPa / s to 35 MPa, and at a rate of 1.0 MPa / s to 2 MPa; then unloaded to atmospheric pressure.

[0064] The high-strength, high-thermal-conductivity silicon carbide support component prepared in this embodiment was tested and found to have a bulk density of 2.98 g / cm³. 3 Thermal conductivity: 113.2 W / (m·K); High-temperature flexural strength: 18.4 MPa (1200℃, 0.5h); Thermal shock resistance: 23 cycles (1100℃, air cooling); Oxide layer thickness: 0.18 mm (1400℃, 2h); Coefficient of thermal expansion (20~1000℃): 4.7×10⁻⁶ -6 / ℃.

[0065] Example 3

[0066] A high-strength, high-thermal-conductivity silicon carbide support component and its preparation method. The preparation method described in this embodiment is as follows:

[0067] Step 1: Prepare the following ingredients: 18 wt% silicon carbide particles with a particle size of 1-2 mm, 27 wt% silicon carbide particles with a particle size of 0.5-1 mm, 14 wt% silicon carbide particles with a particle size of ≤0.5 mm, 37 wt% silicon carbide fine powder with a particle size of ≤0.088 mm, 2 wt% ammonium metavanadate, 1 wt% sintering aid, and 1 wt% binder.

[0068] Step 2: Following the batching method described in Step 1, first add the silicon carbide particles with a particle size of 1-2 mm, silicon carbide particles with a particle size of 0.5-1 mm, and silicon carbide particles with a particle size of ≤0.5 mm to the mixer, then add 4 wt% of anhydrous ethanol from the batching method, and mix for 10 min. Then, add the silicon carbide fine powder, the ammonium metavanadate, the sintering aid, and the binder in sequence, and mix for 13 min to obtain the mixture.

[0069] Step 3: Place the mixture in a mold, seal it, and move it to the pressure chamber of an isostatic press. First, perform a pressurization process, and then a depressurization process to obtain a silicon carbide support component green blank.

[0070] Step 4: Under nitrogen atmosphere, the silicon carbide support component green blank is first heat-treated at 900°C for 2 hours, and then heat-treated at 14500°C for 3 hours to obtain a high-strength, high-thermal-conductivity silicon carbide support component.

[0071] In this embodiment:

[0072] The sintering aid is a mixture of yttrium oxide and lanthanum oxide; wherein the molar ratio of yttrium oxide to lanthanum oxide is 1.1:1.

[0073] The binder is aluminum dihydrogen phosphate, and the FeO content of the liquid aluminum dihydrogen phosphate is ≤0.02wt%.

[0074] The pressurization process is as follows: the pressure is increased sequentially at a rate of 2.0 MPa / s to 35 MPa, at a rate of 4.0 MPa / s to 60 MPa, at a rate of 5.0 MPa / s to 90 MPa, at a rate of 6.0 MPa / s to 125 MPa; then the pressure is increased to 160 MPa at a rate of 5.0 MPa / s, and held for 4 minutes.

[0075] The pressure reduction process is as follows: the pressure is reduced sequentially at a rate of 4.0 MPa / s to 115 MPa, at a rate of 6.0 MPa / s to 90 MPa, at a rate of 4.0 MPa / s to 55 MPa, at a rate of 4.0 MPa / s to 25 MPa, and at a rate of 3.0 MPa / s to 2 MPa; then unloaded to atmospheric pressure.

[0076] The high-strength, high-thermal-conductivity silicon carbide support component prepared in this embodiment was tested and found to have a bulk density of 3.01 g / cm³. 3 Thermal conductivity: 113.2 W / (m·K); High-temperature flexural strength: 17.7 MPa (1200℃, 0.5h); Thermal shock resistance: 22 cycles (1100℃, air cooling); Oxide layer thickness: 0.17 mm (1400℃, 2h); Coefficient of thermal expansion (20~1000℃): 4.9×10⁻⁶ -6 / ℃.

[0077] Example 4

[0078] A high-strength, high-thermal-conductivity silicon carbide support component and its preparation method. The preparation method described in this embodiment is as follows:

[0079] Step 1: Prepare the following ingredients: 20 wt% silicon carbide particles with a particle size of 1-2 mm, 25 wt% silicon carbide particles with a particle size of 0.5-1 mm, 10 wt% silicon carbide particles with a particle size of ≤0.5 mm, 40 wt% silicon carbide fine powder with a particle size of ≤0.088 mm, 3 wt% ammonium metavanadate, 1 wt% sintering aid, and 1 wt% binder.

[0080] Step 2: Following the batching method described in Step 1, first add the silicon carbide particles with a particle size of 1-2 mm, silicon carbide particles with a particle size of 0.5-1 mm, and silicon carbide particles with a particle size of ≤0.5 mm to a mixer, then add 5 wt% anhydrous ethanol from the batching method, and mix for 12 minutes. Then, add the silicon carbide fine powder, the ammonium metavanadate, the sintering aid, and the binder in sequence, and mix for 15 minutes to obtain a mixture.

[0081] Step 3: Place the mixture in a mold, seal it, and move it to the pressure chamber of an isostatic press. First, perform a pressurization process, and then a depressurization process to obtain a silicon carbide support component green blank.

[0082] Step 4: Under nitrogen atmosphere, the silicon carbide support component green blank is first heat-treated at 1000℃ for 3 hours, and then heat-treated at 1500℃ for 4 hours to obtain a high-strength, high-thermal-conductivity silicon carbide support component.

[0083] In this embodiment:

[0084] The sintering aid is a mixture of yttrium oxide and lanthanum oxide; wherein the molar ratio of yttrium oxide to lanthanum oxide is 1.2:1.

[0085] The binder is aluminum dihydrogen phosphate, and the FeO content of the liquid aluminum dihydrogen phosphate is ≤0.02wt%.

[0086] The pressurization process is as follows: the pressure is increased sequentially at a rate of 4.0 MPa / s to 40 MPa, at a rate of 6.0 MPa / s to 70 MPa, at a rate of 8.0 MPa / s to 100 MPa, at a rate of 10.0 MPa / s to 130 MPa; then the pressure is increased to 170 MPa at a rate of 8.0 MPa / s, and held for 5 minutes.

[0087] The pressure reduction process is as follows: the pressure is reduced sequentially at a rate of 5.0 MPa / s to 110 MPa, at a rate of 10.0 MPa / s to 80 MPa, at a rate of 8.0 MPa / s to 50 MPa, at a rate of 6.0 MPa / s to 20 MPa, and at a rate of 4.0 MPa / s to 2 MPa; then unloaded to atmospheric pressure.

[0088] The high-strength, high-thermal-conductivity silicon carbide support component prepared in this embodiment was tested and found to have a bulk density of 3.10 g / cm³. 3 Thermal conductivity: 115.4 W / (m·K); High-temperature flexural strength: 15.3 MPa (1200℃, 0.5h); Thermal shock resistance: 20 cycles (1100℃, air cooling); Oxide layer thickness: 0.15 mm (1400℃, 2h); Coefficient of thermal expansion (20~1000℃): 5.0×10⁻⁶ -6 / ℃.

[0089] This specific implementation method has the following advantages compared with the prior art:

[0090] (1) Based on strictly limiting the particle size distribution of silicon carbide raw materials, this specific embodiment utilizes particle stacking and the decomposition of ammonium metavanadate (2NH4VO3=V2O5+H2O+2NH3) during heat treatment to form an appropriate amount of micropores inside the material. By utilizing the high thermal conductivity and low thermal expansion coefficient of silicon carbide, the prepared high-strength and high-thermal-conductivity silicon carbide support component has high thermal shock stability.

[0091] (2) In this specific embodiment, vanadium pentoxide formed by the decomposition of ammonium metavanadate during heat treatment reacts with impurities in silicon carbide raw materials to form a vanadate liquid phase, which then encapsulates silicon carbide particles in situ, avoiding oxidation of silicon carbide particles during high-temperature use and maintaining their high thermal conductivity. Therefore, the high-strength, high-thermal-conductivity silicon carbide support component prepared in this embodiment has good oxidation resistance and high thermal conductivity.

[0092] (3) The mixture of yttrium oxide and lanthanum oxide used in this specific embodiment not only lowers the sintering temperature of the silicon carbide support component as a sintering aid, but also increases the viscosity of the vanadate and silicate liquid phases at high temperature, thereby increasing the bonding strength between raw material particles and significantly improving the high-temperature flexural strength of the silicon carbide support component. Therefore, the high-strength, high-thermal-conductivity silicon carbide support component prepared has a low sintering temperature and high high-temperature flexural strength.

[0093] The high-strength, high-thermal-conductivity silicon carbide support component prepared according to this specific embodiment was tested and found to have a bulk density of 2.92–3.10 g / cm³. 3 Thermal conductivity ≥100 W / (m·K); High-temperature flexural strength 15–20 MPa (1200℃, 0.5h); Thermal shock resistance ≥20 cycles (1100℃, air cooling); Oxide layer thickness ≤0.20 mm (1400℃, 2h); Coefficient of thermal expansion (20–1000℃) (4.5–5.0) × 10⁻⁶ -6 / ℃.

[0094] Therefore, the high-strength, high-thermal-conductivity silicon carbide support component prepared in this specific embodiment has a low sintering temperature, high high-temperature flexural strength, high thermal shock stability, high thermal conductivity, and good oxidation resistance.

Claims

1. A method for preparing a high-strength, high-thermal-conductivity silicon carbide support component, characterized in that... The preparation method comprises the following steps: Step 1: Prepare the following ingredients: 10-20 wt% silicon carbide particles with a particle size of 1-2 mm, 25-35 wt% silicon carbide particles with a particle size of 0.5-1 mm, 10-20 wt% silicon carbide particles with a particle size of ≤0.5 mm, 30-40 wt% silicon carbide fine powder with a particle size of ≤0.088 mm, 1-3 wt% ammonium metavanadate, 1-2 wt% sintering aid, and 1-2 wt% binder. Step 2: Following the batching method described in Step 1, first add the silicon carbide particles with a particle size of 1-2 mm, silicon carbide particles with a particle size of 0.5-1 mm, and silicon carbide particles with a particle size of ≤0.5 mm to a mixer, then add 3-5 wt% of anhydrous ethanol from the batching method, and mix for 8-12 minutes. Then, add the silicon carbide fine powder, the ammonium metavanadate, the sintering aid, and the binder in sequence, and mix for 10-15 minutes to obtain a mixture. Step 3: Place the mixture in a mold, seal it, and move it to the pressure chamber of an isostatic press. First, perform a pressurization process, and then a depressurization process to obtain a silicon carbide support component green blank. Step 4: Under an argon or nitrogen atmosphere, the silicon carbide support component green blank is first heat-treated at 800-1000℃ for 1-3 hours, and then heat-treated at 1300-1500℃ for 2-4 hours to obtain a high-strength, high-thermal-conductivity silicon carbide support component.

2. The method for preparing a high-strength, high-thermal-conductivity silicon carbide support component according to claim 1, characterized in that... The chemical composition of the silicon carbide particles is: SiC content ≥ 97.0 wt%, Fe2O3 content ≤ 0.5 wt%; the silicon carbide fine powder has the same chemical composition as the silicon carbide particles.

3. The method for preparing a high-strength, high-thermal-conductivity silicon carbide support component according to claim 1, characterized in that... The ammonium metavanadate contains ≥99.0 wt% NH4VO3.

4. The method for preparing a high-strength, high-thermal-conductivity silicon carbide support component according to claim 1, characterized in that... The sintering aid is a mixture of yttrium oxide and lanthanum oxide; wherein the molar ratio of yttrium oxide to lanthanum oxide is 1 to 1.2:

1.

5. The method for preparing a high-strength, high-thermal-conductivity silicon carbide support component according to claim 1, characterized in that... The binder is bisphenol A type epoxy resin or liquid aluminum dihydrogen phosphate; wherein: the purity of the bisphenol A type epoxy resin is ≥98.0wt%, and the FeO content of the liquid aluminum dihydrogen phosphate is ≤0.02wt%.

6. The method for preparing a high-strength, high-thermal-conductivity silicon carbide support member according to claim 1, characterized in that... The pressurization process is as follows: pressurize sequentially at a rate of 0.2–4.0 MPa / s to 25–40 MPa, at a rate of 0.2–6.0 MPa / s to 50–70 MPa, at a rate of 0.2–8.0 MPa / s to 80–100 MPa, at a rate of 0.2–10.0 MPa / s to 110–130 MPa, and at a rate of 0.5–8.0 MPa / s to 140–170 MPa; hold the pressure for 1–5 minutes.

7. The method for preparing a high-strength, high-thermal-conductivity silicon carbide support member according to claim 1, characterized in that... The pressure reduction process is as follows: the pressure is reduced sequentially at a rate of 0.2–5.0 MPa / s to 110–130 MPa, at a rate of 0.2–10.0 MPa / s to 80–100 MPa, at a rate of 0.2–8.0 MPa / s to 50–70 MPa, at a rate of 0.2–6.0 MPa / s to 20–40 MPa, and at a rate of 0.2–4.0 MPa / s to 2 MPa; then unloaded to atmospheric pressure.

8. A high-strength, high-thermal-conductivity silicon carbide support component, characterized in that... The high-strength, high-thermal-conductivity silicon carbide support member is the high-strength, high-thermal-conductivity silicon carbide support member prepared according to the preparation method of any one of claims 1 to 7.