WO2022267103A1 - Seed crystal-induced microwave synthesized sic crystal and preparation method therefor - Google Patents

Seed crystal-induced microwave synthesized sic crystal and preparation method therefor Download PDF

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WO2022267103A1
WO2022267103A1 PCT/CN2021/105386 CN2021105386W WO2022267103A1 WO 2022267103 A1 WO2022267103 A1 WO 2022267103A1 CN 2021105386 W CN2021105386 W CN 2021105386W WO 2022267103 A1 WO2022267103 A1 WO 2022267103A1
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sic
crystals
crystal
seed
induced
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Chinese (zh)
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张锐
关莉
王海龙
李哲
张新月
高前程
赵彪
郭少杰
李明亮
范冰冰
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郑州航空工业管理学院
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Publication of WO2022267103A1 publication Critical patent/WO2022267103A1/en

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
    • C04B35/565—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide
    • C04B35/573—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide obtained by reaction sintering or recrystallisation
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/66—Specific sintering techniques, e.g. centrifugal sintering
    • C04B2235/667—Sintering using wave energy, e.g. microwave sintering
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

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  • the invention relates to the technical field of inorganic non-metallic materials, in particular to a SiC crystal synthesized by seed induced microwaves and a preparation method thereof.
  • SiC has the advantages of high strength, high hardness, high elastic modulus and excellent chemical stability, and is widely used in abrasives, refractory materials, metallurgy, machining and other fields. SiC has a wide energy band gap, high electron mobility, and excellent high-temperature electrical and thermal conductivity. It occupies a very important position in the application fields of electronic device semiconductors and heat exchangers.
  • the current method of industrial production of SiC crystals still mainly adopts the traditional Acheson method.
  • the preparation of SiC crystals by Acheson method has the characteristics of cheap raw materials, simple process, and easy industrial production.
  • its low thermal efficiency, high synthesis temperature, large energy consumption, long cycle, and serious pollution have seriously affected the atmospheric environment; and its complex crystal form and large particle size cannot meet the application requirements of high-end fields.
  • there are more and more new processes for preparing SiC crystals such as sol-gel method, chemical vapor phase synthesis method and solvothermal method.
  • these methods have the disadvantages of complex synthesis steps, high energy consumption, and high production costs.
  • the purpose of the present invention is to solve the deficiencies in the above-mentioned background technology, and to provide a method for preparing SiC crystals by seed crystal induction microwave synthesis.
  • SiC is used as a good microwave absorber material
  • SiC seed crystals are coupled with microwaves to generate heat, which promotes the reaction of raw materials at low temperatures.
  • SiC seed crystals can be used as a crystallization platform at high temperatures to promote crystal nucleation and growth. As a crystal growth hot station, it induces the nucleation and in-situ growth of synthetic SiC.
  • the process in this paper will greatly reduce the difficulty and process conditions of SiC crystal synthesis.
  • Microwave plus seed crystal recombination induced synthesis of SiC has a good application prospect.
  • the first object of the present invention is to provide a method for preparing SiC crystals synthesized by seed crystal induced microwave, comprising the following steps:
  • the mixed powder After uniformly mixing silicon powder, nano-carbon black and SiC seed crystals, the mixed powder is obtained, and then the mixed powder is pressed into a green body, and then heated by microwaves, and kept at 800-1100°C for 15-30 minutes to synthesize SiC crystals.
  • the seed crystal induces microwave synthesis of SiC crystals.
  • the power input rate is 200-600 W/min.
  • the particle size of the SiC seed crystal is 0.5-5 ⁇ m, and its addition amount is 1-20 wt % of the total mass of raw materials.
  • the molar ratio of silicon powder to nano-carbon black is 1:1-3.
  • the mixed powder is mixed with silicon powder, nano-carbon black and SiC seed crystals using absolute ethanol as a dispersion medium by ball milling, with the rotational speed set at 100r/min for 12 hours, and then vacuumed at a temperature of 80°C. Dry for 12h, that is.
  • the particle size of the mixed powder is ⁇ 60 mesh.
  • the green body when the green body is heated, the green body is put into an alumina crucible, and the quartz sand powder is covered around it; Proceed and heat in the microwave.
  • the second object of the present invention is to provide a SiC crystal synthesized by seed crystal induced microwave.
  • the third object of the present invention is to provide an application of SiC crystal in semiconductors of electronic devices and heat exchangers.
  • SiC is used as a good microwave absorber material, and SiC seeds and microwaves are coupled to generate heat, which promotes the reaction of raw materials at low temperatures; SiC seeds can be used as a crystallization platform at high temperatures to promote crystal formation. Nucleation and growth; therefore, during the microwave heating process, the SiC seed crystal can not only make itself a local hot spot to promote the reaction of raw materials, but also serve as a crystal growth hot platform to induce the synthesis of SiC nucleation and in-situ growth. Compared with the current industrial seed crystal induction technology, the process in this paper will greatly reduce the difficulty and process conditions of SiC crystal synthesis; microwave plus seed crystal composite induction synthesis of SiC has a good application prospect.
  • Fig. 1 is the XRD pattern of SiC crystals synthesized by seed crystal induced microwaves provided by raw materials and Examples 1-4.
  • FIG. 2 is a SEM photo of raw materials and seed crystals induced by microwave synthesis of SiC crystals provided in Examples 1-4.
  • Fig. 3 is the XRD pattern of SiC crystals synthesized by seed crystal induced microwaves provided by raw materials and Examples 4-6.
  • FIG. 4 is an SEM photo of SiC crystals synthesized by seed crystals induced by microwaves provided in Examples 4-6.
  • Fig. 5 is the XRD patterns of SiC crystals synthesized by seed crystal induced microwaves provided in Examples 4, 7 and 8.
  • Fig. 6 is a SEM photo of SiC crystals synthesized by seed crystals induced by microwaves provided in Examples 4, 7, and 8.
  • the SiC seed crystals used in the following examples are ⁇ -SiC particles with a purity of 99.9%, purchased from Baofeng Hengrui New Material Co., Ltd.
  • Silicon powder was purchased from Shanghai Chaowei Nano Technology Co., Ltd.; nano-carbon black was purchased from Hebei Xintie Metal Material Co., Ltd.;
  • a method for preparing SiC crystals synthesized by seed crystal induced microwave comprising the following steps:
  • nano-carbon black and silicon powder according to the molar ratio of 2:1 mol, and the amount of 5 ⁇ m SiC seed crystal added is 20 (wt)% of the total mass.
  • absolute ethanol as the dispersion medium, the nano-carbon black, silicon powder and SiC seed crystals with a particle size of 5 ⁇ m were put into a ball mill pot and mixed for 12 hours, and the speed was set at 100 r/min. After the ball milling, put it into a blast drying oven for 12 hours at 80° C., and then sieve it for later use.
  • a green body forming pressure of 2 MPa the mixed powder with a mass of 8 g was uniaxially pressed into a green body of 25 ⁇ 35 ⁇ 10 mm.
  • the green body was put into an alumina crucible and covered with quartz sand powder around it.
  • the crucible was placed in an insulation structure consisting of alumina insulation box and mullite insulation fiber cotton, and heated in a TE666 resonant mode microwave oven (WXD20S-07, Nanjing Sanle Microwave Equipment Co., Ltd.).
  • the microwave frequency is 2.45GHz, and the maximum input power is 10KW; the temperature is measured by an infrared pyrometer, and the initial display starts from 600°C.
  • the incident power is adjusted to a maximum value of 6400W at a rate of 400W/min to control the heating temperature.
  • the heating temperature is 800°C
  • the holding time is 20min
  • the SiC crystal is obtained by the seed crystal induced microwave synthesis.
  • Example 2 Same as Example 1, except that the heating temperature is 900°C.
  • Example 2 Same as Example 1, except that the heating temperature is 1000°C.
  • Example 2 Same as Example 1, except that the heating temperature is 1100°C.
  • a method for preparing SiC crystals synthesized by seed crystal induced microwave comprising the following steps:
  • Nano carbon black and silicon powder were weighed according to the molar ratio of 2:1 mol, and the amount of 5 ⁇ m SiC seed crystal added was 20 (wt)% of the total mass.
  • the nano-carbon black, silicon powder and SiC seed crystals with a particle size of 5 ⁇ m were put into a ball mill pot and mixed for 12 hours, and the speed was set at 100 r/min. After the ball milling, put it into a blast drying oven for 12 hours at 80° C., and then sieve it for later use.
  • Using a green body forming pressure of 2 MPa the mixed powder with a mass of 8 g was uniaxially pressed into a green body of 25 ⁇ 35 ⁇ 10 mm.
  • the green body was put into an alumina crucible and covered with quartz sand powder around it.
  • the crucible was placed in an insulation structure consisting of alumina insulation box and mullite insulation fiber cotton, and heated in a TE666 resonant mode microwave oven (WXD20S-07, Nanjing Sanle Microwave Equipment Co., Ltd.).
  • the microwave frequency is 2.45GHz and the maximum input power is 10KW.
  • the temperature is measured by an infrared pyrometer.
  • the initial display starts from 600°C.
  • the incident power is adjusted to a maximum value of 6400W at a rate of 200W/min to control the heating rate.
  • the heating temperature is selected as 1100°C, and the holding time is 20min. Microwave synthesis of SiC crystals.
  • Example 5 Same as Example 5, except that the heating rate was controlled by adjusting the incident power to a maximum value of 6400 W at a rate of 600 W/min.
  • a method for preparing SiC crystals synthesized by seed crystal induced microwave comprising the following steps:
  • Nano carbon black and silicon powder were weighed according to the molar ratio of 2:1 mol, and the addition amount of 0.5 ⁇ m SiC seed crystal was 20 (wt)% of the total mass respectively.
  • absolute ethanol as a dispersion medium, put nano-carbon black, silicon powder, and SiC seeds with a particle size of 0.5 ⁇ m into a ball mill jar for 12 hours, and set the speed at 100 r/min. After the ball milling, put it into a blast drying oven for 12 hours at 80° C., and then sieve it for later use.
  • a green body forming pressure of 2 MPa the mixed powder with a mass of 8 g was uniaxially pressed into a green body of 25 ⁇ 35 ⁇ 10 mm.
  • the green body was put into an alumina crucible and covered with quartz sand powder around it.
  • the crucible was placed in an insulation structure consisting of alumina insulation box and mullite insulation fiber cotton, and heated in a TE666 resonant mode microwave oven (WXD20S-07, Nanjing Sanle Microwave Equipment Co., Ltd.).
  • the microwave frequency is 2.45GHz and the maximum input power is 10KW.
  • the temperature is measured by an infrared pyrometer with an initial display starting at 600°C. The experiment adjusted the incident power to a maximum value of 6400W at a rate of 400W/min to control the heating rate.
  • the heating temperature is selected to be 1100° C., and the holding time is 20 minutes to obtain SiC crystals synthesized by seed crystals induced by microwaves.
  • the SiC seed crystal grain size is about 1 ⁇ m.
  • phase composition and microscopic morphology of the product were characterized by X-ray diffractometer (XRD, SmartLab Japan Rigaku Co., Ltd.) and scanning electron microscope (SEM, JSM 7001F JEOL Ltd.).
  • Fig. 1 is the XRD pattern of SiC crystals synthesized by seed crystal induced microwaves provided by raw materials and Examples 1-4.
  • the raw material in Figure 1 is the XRD pattern of nano-carbon black, silicon powder and SiC seed crystal mixed by ball milling. It can be seen from Figure 1 that the power input rate is 400W/min, and the particle size of SiC seed crystal is 5 ⁇ m. It can be seen from Figure 1 that the raw materials can be fully reacted at 800°C for 20 minutes, and SiC crystals can be synthesized. And as the temperature increases, the crystallinity becomes better and better.
  • FIG. 2 is a SEM photo of raw materials and seed crystals induced by microwave synthesis of SiC crystals provided in Examples 1-4.
  • the raw material in Fig. 2 is the scanning electron microscope picture of nano-carbon black, silicon powder and SiC seed crystal mixed by ball milling. It can be seen from Fig. 2 that there are small particles of nano-SiC attached to the silicon carbide seed crystal at 800 ° C. As the temperature rises, the newly synthesized silicon carbide crystals gradually nucleate and grow on the silicon carbide seeds, and growth steps appear as shown in Figure 2. It shows that the silicon carbide seed promotes the reaction of raw materials to induce nucleation at low temperature, and becomes a hot platform for the growth of silicon carbide crystal at high temperature.
  • Fig. 3 is the XRD spectrum of the SiC crystal seed induced microwave synthesis SiC crystal that raw material and embodiment 4 ⁇ 6 provide, and Fig. 3 shows that raw material is that nano carbon black, silicon powder and SiC crystal seed are obtained after ball mill mixing. XRD patterns, and phase changes of SiC crystals synthesized by seed crystals induced by microwave at 200W/min, 400W/min, and 600W/min power input rates.
  • Fig. 3 a is that raw material is the XRD spectrum of the mixed material obtained after ball milling and mixing nano carbon black, silicon powder and SiC crystal seeds
  • Fig. 3 b is the XRD spectrum of SiC crystals synthesized by seed crystal induction microwave provided in Example 5
  • Fig. 3c is the XRD spectrum of SiC crystals synthesized by seed crystals induced by microwave in Example 4
  • FIG. 3d is the XRD spectrum of SiC crystals synthesized by seed crystals induced by microwaves in Example 6;
  • Fig. 4 is the SEM photo of SiC crystals synthesized by seed crystals induced by microwaves provided in Examples 4-6. changes in appearance.
  • Fig. 4a is the SEM photograph of the SiC crystal synthesized by seed crystal induction microwave provided in Example 5
  • Fig. 4b is the SEM photograph of SiC crystal synthesized by seed crystal induction microwave provided in Example 4; Synthetic SiC crystal SEM photo;
  • the temperature is raised to 1100°C for 20 minutes at a heating rate of 200W/min, and the heating rate is slower, and the synthesized silicon carbide crystals have a smaller particle size.
  • the synthesized silicon carbide crystals have larger particle size, clear outline and better crystal morphology and structure under the heating rate of 400W/min and 600W/min.
  • FIG. 5 is the XRD spectrum of the SiC crystals synthesized by seed crystals induced by microwaves provided in Examples 4, 7, and 8.
  • Figure 5 shows the SiC crystals synthesized by seed crystals induced by microwaves under the conditions of adding SiC seeds with particle sizes of 0.5 ⁇ m, 1 ⁇ m, and 5 ⁇ m, respectively. change of phase.
  • FIG. 6a is the SiC crystal XRD spectrum provided in Example 7
  • FIG. 6b is the SiC crystal XRD spectrum provided in Example 8
  • FIG. 6c is the SiC crystal XRD spectrum provided in Example 4;
  • Figure 6 is the SEM photo of SiC crystals synthesized by seed crystals induced by microwaves provided in Examples 4, 7, and 8.
  • Figure 6 shows the SiC crystals synthesized by seed crystals induced by microwaves under the conditions of adding SiC seeds with particle sizes of 0.5 ⁇ m, 1 ⁇ m, and 5 ⁇ m, respectively. Changes in microscopic morphology.
  • Figure 6a is the SEM photo of the SiC crystal provided in Example 7
  • Figure 6b is the SEM photo of the SiC crystal provided in Example 8
  • Figure 6c is the SEM photo of the SiC crystal provided in Example 4;
  • SiC is used as a good microwave absorber material, and SiC seed crystals are coupled with microwaves to generate heat, which promotes the reaction of raw materials at low temperatures; SiC seed crystals can be used as crystallization at high temperatures. Therefore, during the microwave heating process, the SiC seed crystal can not only make itself a local hot spot to promote the reaction of raw materials, but also serve as a crystal growth hot platform to induce the synthesis of SiC nucleation and in-situ growth. Compared with the current industrial seed crystal induction technology, the process in this paper will greatly reduce the difficulty and process conditions of SiC crystal synthesis; microwave plus seed crystal composite induction synthesis of SiC has a good application prospect.

Abstract

A seed crystal-induced microwave synthesized SiC crystal and a preparation method therefor, relating to the technical field of inorganic nonmetallic materials. The method comprises the following steps: after uniformly mixing silicon powder, nano-carbon black, and a SiC seed crystal to obtain mixed powder, then pressing the mixed powder into a blank, then performing microwave heating, and maintaining the temperature at 800-1,100ºC for 15-30 minutes to synthesize a SiC crystal, i.e., the seed crystal-induced microwave synthesized SiC crystal. Compared with the current seed crystal induction technology in industry, the method greatly reduces the difficulty and process conditions of SiC crystal synthesis, and has good application prospects.

Description

[根据细则37.2由ISA制定的发明名称]　晶种诱导微波合成的SIC晶体及其制备方法[Title of the invention established by ISA under Rule 37.2] SIC crystals synthesized by seed-induced microwave synthesis and methods for their preparation 技术领域technical field
本发明涉及无机非金属材料技术领域，具体涉及一种晶种诱导微波合成的SiC晶体及其制备方法。The invention relates to the technical field of inorganic non-metallic materials, in particular to a SiC crystal synthesized by seed induced microwaves and a preparation method thereof.
背景技术Background technique
SiC具有高强度、高硬度、高弹性模量和优良的化学稳定性等优点，被广泛应用于磨料磨具、耐火材料、冶金、机械加工等领域。SiC能带间隙宽，电子迁移率高，高温导电导热性能优良，在电子器件半导体和换热器应用领域占有十分重要的地位。SiC has the advantages of high strength, high hardness, high elastic modulus and excellent chemical stability, and is widely used in abrasives, refractory materials, metallurgy, machining and other fields. SiC has a wide energy band gap, high electron mobility, and excellent high-temperature electrical and thermal conductivity. It occupies a very important position in the application fields of electronic device semiconductors and heat exchangers.
目前工业化生产SiC晶体的方法仍主要采用传统的Acheson法。Acheson法制备SiC晶体具有原料便宜、工艺简单、易于实现工业化生产等特点。然而，其热效率低、合成温度高、能耗较大，周期较长，污染严重，给大气环境带来了严重影响；并且晶型复杂，粒径较大，无法满足高端领域的应用需求。近年来，制备SiC晶体的新型工艺越来越多，如溶胶-凝胶法、化学气相合成法及溶剂热法等。但是这些方法存在合成步骤复杂，能耗高，生产成本高等不足。The current method of industrial production of SiC crystals still mainly adopts the traditional Acheson method. The preparation of SiC crystals by Acheson method has the characteristics of cheap raw materials, simple process, and easy industrial production. However, its low thermal efficiency, high synthesis temperature, large energy consumption, long cycle, and serious pollution have seriously affected the atmospheric environment; and its complex crystal form and large particle size cannot meet the application requirements of high-end fields. In recent years, there are more and more new processes for preparing SiC crystals, such as sol-gel method, chemical vapor phase synthesis method and solvothermal method. However, these methods have the disadvantages of complex synthesis steps, high energy consumption, and high production costs.
发明内容Contents of the invention
本发明的目的是为了解决上述背景技术中存在的不足，提供一种晶种诱导微波合成SiC晶体的制备方法，该方法在晶种诱导微波合成SiC的过程中，SiC作为良好的微波吸收体材料，SiC晶种与微波耦合产生热量，低温下促进原料反应，高温下SiC晶种可以作为析晶平台，促进晶体形核与生长，SiC晶种既可使自身成为局部热点促进原料反应，又可作为晶体生长热台，诱导合成SiC 形核与原位生长。相比于工业上现用的晶种诱导技术，本文工艺将极大的降低SiC晶体合成的难度和工艺条件。微波加晶种复合诱导合成SiC具有良好的应用前景。The purpose of the present invention is to solve the deficiencies in the above-mentioned background technology, and to provide a method for preparing SiC crystals by seed crystal induction microwave synthesis. In the process of seed crystal induction microwave synthesis of SiC, SiC is used as a good microwave absorber material , SiC seed crystals are coupled with microwaves to generate heat, which promotes the reaction of raw materials at low temperatures. SiC seed crystals can be used as a crystallization platform at high temperatures to promote crystal nucleation and growth. As a crystal growth hot station, it induces the nucleation and in-situ growth of synthetic SiC. Compared with the seed crystal induction technology currently used in industry, the process in this paper will greatly reduce the difficulty and process conditions of SiC crystal synthesis. Microwave plus seed crystal recombination induced synthesis of SiC has a good application prospect.
本发明第一个目的是提供一种晶种诱导微波合成SiC晶体的制备方法，包括以下步骤：The first object of the present invention is to provide a method for preparing SiC crystals synthesized by seed crystal induced microwave, comprising the following steps:
将硅粉、纳米碳黑及SiC晶种均匀混合后，获得混合粉体，再将混合粉体压制成坯体，随后采用微波加热，于800～1100℃保温15～30min合成SiC晶体，即得所述晶种诱导微波合成SiC晶体。After uniformly mixing silicon powder, nano-carbon black and SiC seed crystals, the mixed powder is obtained, and then the mixed powder is pressed into a green body, and then heated by microwaves, and kept at 800-1100°C for 15-30 minutes to synthesize SiC crystals. The seed crystal induces microwave synthesis of SiC crystals.
优选的，所述微波加热过程中，功率的输入速率为200～600W/min。Preferably, during the microwave heating process, the power input rate is 200-600 W/min.
优选的，所述SiC晶种粒径为0.5～5μm，其加入量为原料总质量的1～20wt％。Preferably, the particle size of the SiC seed crystal is 0.5-5 μm, and its addition amount is 1-20 wt % of the total mass of raw materials.
优选的，所述硅粉与纳米碳黑摩尔比为1：1～3。Preferably, the molar ratio of silicon powder to nano-carbon black is 1:1-3.
优选的，所述混合粉体是将硅粉、纳米碳黑及SiC晶种以无水乙醇作为分散介质采用球磨法进行混料，转速设置为100r/min球磨12h，然后以80℃的温度真空干燥12h，即得。Preferably, the mixed powder is mixed with silicon powder, nano-carbon black and SiC seed crystals using absolute ethanol as a dispersion medium by ball milling, with the rotational speed set at 100r/min for 12 hours, and then vacuumed at a temperature of 80°C. Dry for 12h, that is.
更优选的，所述混合粉体的粒径≥60目。More preferably, the particle size of the mixed powder is ≥60 mesh.
优选的，坯体加热时，将坯体放入氧化铝坩埚内，并在其四周覆盖石英砂粉末；再将坩埚放入具有氧化铝保温箱和莫来石保温纤维棉构成的保温结构中，进行并在微波加热。Preferably, when the green body is heated, the green body is put into an alumina crucible, and the quartz sand powder is covered around it; Proceed and heat in the microwave.
本发明第二个目的是提供一种晶种诱导微波合成的SiC晶体。The second object of the present invention is to provide a SiC crystal synthesized by seed crystal induced microwave.
本发明第三个目的是提供一种SiC晶体在电子器件半导体和换热器中的应用。The third object of the present invention is to provide an application of SiC crystal in semiconductors of electronic devices and heat exchangers.
与现有技术相比，本发明的有益效果是：Compared with prior art, the beneficial effect of the present invention is:
本发明晶种诱导微波合成SiC的过程中，SiC作为良好的微波吸收体材料，SiC晶种与微波耦合产生热量，低温下促进原料反应；高温下SiC晶种可以作为析晶平台，促进晶体形核与生长；因此在微波加热过程中，SiC晶种既可使自身成为局部热点促进原料反应，又可作为晶体生长热台，诱导合成SiC形核 与原位生长。相比于工业上现用的晶种诱导技术，本文工艺将极大的降低SiC晶体合成的难度和工艺条件；微波加晶种复合诱导合成SiC具有良好的应用前景。In the process of SiC synthesized by seed crystals induced by microwaves in the present invention, SiC is used as a good microwave absorber material, and SiC seeds and microwaves are coupled to generate heat, which promotes the reaction of raw materials at low temperatures; SiC seeds can be used as a crystallization platform at high temperatures to promote crystal formation. Nucleation and growth; therefore, during the microwave heating process, the SiC seed crystal can not only make itself a local hot spot to promote the reaction of raw materials, but also serve as a crystal growth hot platform to induce the synthesis of SiC nucleation and in-situ growth. Compared with the current industrial seed crystal induction technology, the process in this paper will greatly reduce the difficulty and process conditions of SiC crystal synthesis; microwave plus seed crystal composite induction synthesis of SiC has a good application prospect.
附图说明Description of drawings
图1为原料及实施例1～4提供的晶种诱导微波合成SiC晶体XRD图谱。Fig. 1 is the XRD pattern of SiC crystals synthesized by seed crystal induced microwaves provided by raw materials and Examples 1-4.
图2为原料及实施例1～4提供的晶种诱导微波合成SiC晶体SEM照片。FIG. 2 is a SEM photo of raw materials and seed crystals induced by microwave synthesis of SiC crystals provided in Examples 1-4.
图3为原料及实施例4～6提供的晶种诱导微波合成SiC晶体XRD图谱。Fig. 3 is the XRD pattern of SiC crystals synthesized by seed crystal induced microwaves provided by raw materials and Examples 4-6.
图4为实施例4～6提供的晶种诱导微波合成SiC晶体SEM照片。FIG. 4 is an SEM photo of SiC crystals synthesized by seed crystals induced by microwaves provided in Examples 4-6.
图5为实施例4、7、8提供的晶种诱导微波合成SiC晶体XRD图谱。Fig. 5 is the XRD patterns of SiC crystals synthesized by seed crystal induced microwaves provided in Examples 4, 7 and 8.
图6为实施例4、7、8提供的晶种诱导微波合成SiC晶体SEM照片。Fig. 6 is a SEM photo of SiC crystals synthesized by seed crystals induced by microwaves provided in Examples 4, 7, and 8.
具体实施方式detailed description
为了使本领域技术人员更好地理解本发明的技术方案能予以实施，下面结合具体实施例和附图对本发明作进一步说明，但所举实施例不作为对本发明的限定。In order to enable those skilled in the art to better understand that the technical solutions of the present invention can be implemented, the present invention will be further described below in conjunction with specific examples and accompanying drawings, but the given examples are not intended to limit the present invention.
需要说明的是，下述各实施例中所述实验方法如无特殊说明，均为常规方法；采用的试剂和材料，如无特殊说明，均可在市场上购买得到。It should be noted that, unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials used, unless otherwise specified, can be purchased in the market.
下述各实施例采用的SiC晶种类型为α-SiC颗粒，纯度为99.9％，购自宝丰恒瑞新材料有限公司。The SiC seed crystals used in the following examples are α-SiC particles with a purity of 99.9%, purchased from Baofeng Hengrui New Material Co., Ltd.
硅粉购自上海超威纳米科技有限公司；纳米炭黑购自河北鑫铁金属材料有限公司；Silicon powder was purchased from Shanghai Chaowei Nano Technology Co., Ltd.; nano-carbon black was purchased from Hebei Xintie Metal Material Co., Ltd.;
下面结合具体实施例对本发明的技术方案作进一步的描述。The technical solutions of the present invention will be further described below in conjunction with specific embodiments.
实施例1Example 1
一种晶种诱导微波合成SiC晶体的制备方法，包括以下步骤：A method for preparing SiC crystals synthesized by seed crystal induced microwave, comprising the following steps:
将纳米碳黑与硅粉按照摩尔比2：1mol称量，5μm的SiC晶种的加入量为 总质量的20(wt)％。以无水乙醇作为分散介质将纳米碳黑、硅粉及粒径为5μm的SiC晶种分别放入球磨罐中球磨混料12小时，转速设置为100r/min。球磨结束后放入鼓风干燥箱80℃干燥12小时，然后过筛备用。采用2MPa的坯体成型压力将质量为8g混合粉体单轴压制成25×35×10毫米的坯体。为防止其在微波合成过程中氧化，将坯体放入氧化铝坩埚内，并在其四周覆盖石英砂粉末。将坩埚放入具有氧化铝保温箱和莫来石保温纤维棉构成的保温结构中，并在TE666谐振模式的微波炉中加热(WXD20S-07，南京三乐微波设备有限公司)。微波频率为2.45GHz，最大输入功率为10KW；温度由红外高温计测量，初始显示从600℃开始，实验以400W/min的速率调节入射功率至最大值6400W来控制加热温度，加热温度为800℃，保温时间为20min，即得晶种诱导微波合成SiC晶体。Weigh nano-carbon black and silicon powder according to the molar ratio of 2:1 mol, and the amount of 5 μm SiC seed crystal added is 20 (wt)% of the total mass. Using absolute ethanol as the dispersion medium, the nano-carbon black, silicon powder and SiC seed crystals with a particle size of 5 μm were put into a ball mill pot and mixed for 12 hours, and the speed was set at 100 r/min. After the ball milling, put it into a blast drying oven for 12 hours at 80° C., and then sieve it for later use. Using a green body forming pressure of 2 MPa, the mixed powder with a mass of 8 g was uniaxially pressed into a green body of 25×35×10 mm. In order to prevent its oxidation during the microwave synthesis process, the green body was put into an alumina crucible and covered with quartz sand powder around it. The crucible was placed in an insulation structure consisting of alumina insulation box and mullite insulation fiber cotton, and heated in a TE666 resonant mode microwave oven (WXD20S-07, Nanjing Sanle Microwave Equipment Co., Ltd.). The microwave frequency is 2.45GHz, and the maximum input power is 10KW; the temperature is measured by an infrared pyrometer, and the initial display starts from 600°C. In the experiment, the incident power is adjusted to a maximum value of 6400W at a rate of 400W/min to control the heating temperature. The heating temperature is 800°C , the holding time is 20min, and the SiC crystal is obtained by the seed crystal induced microwave synthesis.
实施例2Example 2
与实施例1相同，不同之处在于，加热温度为900℃。Same as Example 1, except that the heating temperature is 900°C.
实施例3Example 3
与实施例1相同，不同之处在于，加热温度为1000℃。Same as Example 1, except that the heating temperature is 1000°C.
实施例4Example 4
与实施例1相同，不同之处在于，加热温度为1100℃。Same as Example 1, except that the heating temperature is 1100°C.
实施例5Example 5
一种晶种诱导微波合成SiC晶体的制备方法，包括以下步骤：A method for preparing SiC crystals synthesized by seed crystal induced microwave, comprising the following steps:
将纳米碳黑与硅粉按照摩尔比2：1mol称量，5μm的SiC晶种的加入量为总质量的20(wt)％。以无水乙醇作为分散介质将纳米碳黑、硅粉及粒径为5μm的SiC晶种分别放入球磨罐中球磨混料12小时，转速设置为100r/min。 球磨结束后放入鼓风干燥箱80℃干燥12小时，然后过筛备用。采用2MPa的坯体成型压力将质量为8g混合粉体单轴压制成25×35×10毫米的坯体。为防止其在微波合成过程中氧化，将坯体放入氧化铝坩埚内，并在其四周覆盖石英砂粉末。将坩埚放入具有氧化铝保温箱和莫来石保温纤维棉构成的保温结构中，并在TE666谐振模式的微波炉中加热(WXD20S-07，南京三乐微波设备有限公司)。微波频率为2.45GHz，最大输入功率为10KW。温度由红外高温计测量，初始显示从600℃开始，实验以200W/min的速率调节入射功率至最大值6400W来控制加热速率，加热温度选择为1100℃，保温时间为20min，即得晶种诱导微波合成SiC晶体。Nano carbon black and silicon powder were weighed according to the molar ratio of 2:1 mol, and the amount of 5 μm SiC seed crystal added was 20 (wt)% of the total mass. Using absolute ethanol as the dispersion medium, the nano-carbon black, silicon powder and SiC seed crystals with a particle size of 5 μm were put into a ball mill pot and mixed for 12 hours, and the speed was set at 100 r/min. After the ball milling, put it into a blast drying oven for 12 hours at 80° C., and then sieve it for later use. Using a green body forming pressure of 2 MPa, the mixed powder with a mass of 8 g was uniaxially pressed into a green body of 25×35×10 mm. In order to prevent its oxidation during the microwave synthesis process, the green body was put into an alumina crucible and covered with quartz sand powder around it. The crucible was placed in an insulation structure consisting of alumina insulation box and mullite insulation fiber cotton, and heated in a TE666 resonant mode microwave oven (WXD20S-07, Nanjing Sanle Microwave Equipment Co., Ltd.). The microwave frequency is 2.45GHz and the maximum input power is 10KW. The temperature is measured by an infrared pyrometer. The initial display starts from 600°C. In the experiment, the incident power is adjusted to a maximum value of 6400W at a rate of 200W/min to control the heating rate. The heating temperature is selected as 1100°C, and the holding time is 20min. Microwave synthesis of SiC crystals.
实施例6Example 6
与实施例5相同，不同之处在于，以600W/min的速率调节入射功率至最大值6400W来控制加热速率。Same as Example 5, except that the heating rate was controlled by adjusting the incident power to a maximum value of 6400 W at a rate of 600 W/min.
实施例7Example 7
一种晶种诱导微波合成SiC晶体的制备方法，包括以下步骤：A method for preparing SiC crystals synthesized by seed crystal induced microwave, comprising the following steps:
将纳米碳黑与硅粉按照摩尔比2：1mol称量，0.5μm的SiC晶种的加入量分别均为总质量的20(wt)％。以无水乙醇作为分散介质将纳米碳黑、硅粉及粒径为0.5μm的SiC晶种分别放入球磨罐中球磨混料12小时，转速设置为100r/min。球磨结束后放入鼓风干燥箱80℃干燥12小时，然后过筛备用。采用2MPa的坯体成型压力将质量为8g混合粉体单轴压制成25×35×10毫米的坯体。为防止其在微波合成过程中氧化，将坯体放入氧化铝坩埚内，并在其四周覆盖石英砂粉末。将坩埚放入具有氧化铝保温箱和莫来石保温纤维棉构成的保温结构中，并在TE666谐振模式的微波炉中加热(WXD20S-07，南京三乐微波设备有限公司)。微波频率为2.45GHz，最大输入功率为10KW。温度由红外高温计测量，初始显示从600℃开始。实验分别以400W/min的速率调节入 射功率至最大值6400W来控制加热速率。加热温度选择为1100℃，保温时间为20min，即得晶种诱导微波合成SiC晶体。Nano carbon black and silicon powder were weighed according to the molar ratio of 2:1 mol, and the addition amount of 0.5 μm SiC seed crystal was 20 (wt)% of the total mass respectively. Using absolute ethanol as a dispersion medium, put nano-carbon black, silicon powder, and SiC seeds with a particle size of 0.5 μm into a ball mill jar for 12 hours, and set the speed at 100 r/min. After the ball milling, put it into a blast drying oven for 12 hours at 80° C., and then sieve it for later use. Using a green body forming pressure of 2 MPa, the mixed powder with a mass of 8 g was uniaxially pressed into a green body of 25×35×10 mm. In order to prevent its oxidation during the microwave synthesis process, the green body was put into an alumina crucible and covered with quartz sand powder around it. The crucible was placed in an insulation structure consisting of alumina insulation box and mullite insulation fiber cotton, and heated in a TE666 resonant mode microwave oven (WXD20S-07, Nanjing Sanle Microwave Equipment Co., Ltd.). The microwave frequency is 2.45GHz and the maximum input power is 10KW. The temperature is measured by an infrared pyrometer with an initial display starting at 600°C. The experiment adjusted the incident power to a maximum value of 6400W at a rate of 400W/min to control the heating rate. The heating temperature is selected to be 1100° C., and the holding time is 20 minutes to obtain SiC crystals synthesized by seed crystals induced by microwaves.
实施例8Example 8
与实施例7相同，不同之处在于，SiC晶种粒径约为1μm。Same as Example 7, except that the SiC seed crystal grain size is about 1 μm.
为了说明本发明提供制备方法制得的SiC晶体的相关性能，对实施例1～10提供的SiC晶体进行相关性能的测试，具体见图1～6所示。In order to illustrate the related properties of the SiC crystals prepared by the preparation method provided by the present invention, the related properties of the SiC crystals provided in Examples 1-10 were tested, as shown in FIGS. 1-6 for details.
采用X射线衍射仪(XRD，SmartLab日本理学株式会)和扫描电子显微镜(SEM，JSM 7001F日本电子株氏会)对产物的物相组成、微观形貌进行表征。The phase composition and microscopic morphology of the product were characterized by X-ray diffractometer (XRD, SmartLab Japan Rigaku Co., Ltd.) and scanning electron microscope (SEM, JSM 7001F JEOL Ltd.).
发明结果如下：The results of the invention are as follows:
1、温度对晶种诱导微波合成SiC晶体的影响1. Effect of temperature on seed crystal induced microwave synthesis of SiC crystal
图1为原料及实施例1～4提供的晶种诱导微波合成SiC晶体XRD图谱。图1中的原料是将纳米碳黑、硅粉及SiC晶种经球磨混料后的XRD图谱，从图1可知，功率输入速率为400W/min，SiC晶种粒度为5μm。从图1可以看出在800℃保温20min即可实现原料的充分反应，合成出SiC晶体。并且随着温度的升高，结晶度越来越好。Fig. 1 is the XRD pattern of SiC crystals synthesized by seed crystal induced microwaves provided by raw materials and Examples 1-4. The raw material in Figure 1 is the XRD pattern of nano-carbon black, silicon powder and SiC seed crystal mixed by ball milling. It can be seen from Figure 1 that the power input rate is 400W/min, and the particle size of SiC seed crystal is 5μm. It can be seen from Figure 1 that the raw materials can be fully reacted at 800°C for 20 minutes, and SiC crystals can be synthesized. And as the temperature increases, the crystallinity becomes better and better.
图2为原料及实施例1～4提供的晶种诱导微波合成SiC晶体SEM照片。FIG. 2 is a SEM photo of raw materials and seed crystals induced by microwave synthesis of SiC crystals provided in Examples 1-4.
图2中的原料是将纳米碳黑、硅粉及SiC晶种经球磨混料后的扫描电镜图片，从图2可以看出在800℃存在小颗粒纳米SiC附着在碳化硅晶种上，随着温度升高，新合成的碳化硅晶体逐渐在碳化硅晶种上形核与长大，并出现生长台阶如图2所示。说明碳化硅晶种在低温下促进原料反应诱导形核，高温下成为碳化硅晶体生长的热台。The raw material in Fig. 2 is the scanning electron microscope picture of nano-carbon black, silicon powder and SiC seed crystal mixed by ball milling. It can be seen from Fig. 2 that there are small particles of nano-SiC attached to the silicon carbide seed crystal at 800 ° C. As the temperature rises, the newly synthesized silicon carbide crystals gradually nucleate and grow on the silicon carbide seeds, and growth steps appear as shown in Figure 2. It shows that the silicon carbide seed promotes the reaction of raw materials to induce nucleation at low temperature, and becomes a hot platform for the growth of silicon carbide crystal at high temperature.
2、升温速率对晶种诱导微波合成SiC晶体的影响。2. The influence of the heating rate on the seed-induced microwave synthesis of SiC crystals.
图3为原料及实施例4～6提供的晶种诱导微波合成SiC晶体XRD图谱，图3所示为原料是将纳米碳黑、硅粉和SiC晶种经球磨混料后获得的混合料的 XRD图谱，及200W/min、400W/min、600W/min功率输入速率下晶种诱导微波合成SiC晶体物相的变化。其中，图3a为原料是将纳米碳黑、硅粉和SiC晶种经球磨混料后获得的混合料的XRD图谱；图3b为实施例5提供的晶种诱导微波合成SiC晶体XRD图谱；图3c为实施例4提供的晶种诱导微波合成SiC晶体XRD图谱；图3d为实施例6提供的晶种诱导微波合成SiC晶体XRD图谱；Fig. 3 is the XRD spectrum of the SiC crystal seed induced microwave synthesis SiC crystal that raw material and embodiment 4～6 provide, and Fig. 3 shows that raw material is that nano carbon black, silicon powder and SiC crystal seed are obtained after ball mill mixing. XRD patterns, and phase changes of SiC crystals synthesized by seed crystals induced by microwave at 200W/min, 400W/min, and 600W/min power input rates. Wherein, Fig. 3 a is that raw material is the XRD spectrum of the mixed material obtained after ball milling and mixing nano carbon black, silicon powder and SiC crystal seeds; Fig. 3 b is the XRD spectrum of SiC crystals synthesized by seed crystal induction microwave provided in Example 5; Fig. 3c is the XRD spectrum of SiC crystals synthesized by seed crystals induced by microwave in Example 4; FIG. 3d is the XRD spectrum of SiC crystals synthesized by seed crystals induced by microwaves in Example 6;
从图3可以看出在200W/min、400W/min、600W/min功率输入速率下升温至1100℃保温20min均可实现原料的充分反应，合成出SiC晶体。并且随着升温速率的升高，结晶度越来越好。It can be seen from Figure 3 that when the temperature is raised to 1100°C for 20 minutes at the power input rate of 200W/min, 400W/min, and 600W/min, the raw materials can be fully reacted and SiC crystals can be synthesized. And as the heating rate increases, the crystallinity becomes better and better.
图4为实施例4～6提供的晶种诱导微波合成SiC晶体SEM照片，图4所示为分别以200W/min、400W/min、600W/min功率输入速率晶种诱导微波合成SiC晶体微观形貌的变化。其中，图4a为实施例5提供的晶种诱导微波合成SiC晶体SEM照片；图4b为实施例4提供的晶种诱导微波合成SiC晶体SEM照片；图4c为实施例6提供的晶种诱导微波合成SiC晶体SEM照片；Fig. 4 is the SEM photo of SiC crystals synthesized by seed crystals induced by microwaves provided in Examples 4-6. changes in appearance. Wherein, Fig. 4a is the SEM photograph of the SiC crystal synthesized by seed crystal induction microwave provided in Example 5; Fig. 4b is the SEM photograph of SiC crystal synthesized by seed crystal induction microwave provided in Example 4; Synthetic SiC crystal SEM photo;
从图4可以看出以200W/min的升温速率升温至1100℃保温20min，升温速率较慢，合成出的碳化硅晶体粒径较小。随着输入功率增加，在400W/min、600W/min升温速率下，合成的碳化硅晶体粒径较大，轮廓分明，晶体形貌和结构更好。It can be seen from Figure 4 that the temperature is raised to 1100°C for 20 minutes at a heating rate of 200W/min, and the heating rate is slower, and the synthesized silicon carbide crystals have a smaller particle size. With the increase of input power, the synthesized silicon carbide crystals have larger particle size, clear outline and better crystal morphology and structure under the heating rate of 400W/min and 600W/min.
3、SiC晶种粒径对晶种诱导微波合成SiC晶体的影响。3. The effect of SiC seed size on the seed-induced microwave synthesis of SiC crystals.
图5为实施例4、7、8提供的晶种诱导微波合成SiC晶体XRD图谱，图5所示为分别添加0.5μm、1μm、5μm粒径的SiC晶种条件下晶种诱导微波合成SiC晶体物相的变化。其中，图6a为实施例7提供的SiC晶体XRD图谱，图6b为实施例8提供的SiC晶体XRD图谱，图6c为实施例4提供的SiC晶体XRD图谱；Figure 5 is the XRD spectrum of the SiC crystals synthesized by seed crystals induced by microwaves provided in Examples 4, 7, and 8. Figure 5 shows the SiC crystals synthesized by seed crystals induced by microwaves under the conditions of adding SiC seeds with particle sizes of 0.5 μm, 1 μm, and 5 μm, respectively. change of phase. Wherein, FIG. 6a is the SiC crystal XRD spectrum provided in Example 7, FIG. 6b is the SiC crystal XRD spectrum provided in Example 8, and FIG. 6c is the SiC crystal XRD spectrum provided in Example 4;
从图5可以看出在分别添加0.5μm、1μm、5μm粒径的SiC晶种条件下，以400W/min升温速率升温至1100℃保温20min均可实现原料的充分反应，合 成出SiC晶体。并且随SiC晶种粒度的增加，结晶度越来越好。It can be seen from Figure 5 that under the condition of adding SiC seed crystals with particle sizes of 0.5 μm, 1 μm, and 5 μm respectively, the raw materials can be fully reacted and SiC crystals can be synthesized by heating up to 1100 ° C at a heating rate of 400 W/min and holding for 20 minutes. And with the increase of SiC seed crystal size, the crystallinity is getting better and better.
图6为实施例4、7、8提供的晶种诱导微波合成SiC晶体SEM照片，图6所示为分别添加0.5μm、1μm、5μm粒径的SiC晶种条件下晶种诱导微波合成SiC晶体微观形貌的变化。其中，图6a为实施例7提供的SiC晶体SEM照片，图6b为实施例8提供的SiC晶体SEM照片，图6c为实施例4提供的SiC晶体SEM照片；Figure 6 is the SEM photo of SiC crystals synthesized by seed crystals induced by microwaves provided in Examples 4, 7, and 8. Figure 6 shows the SiC crystals synthesized by seed crystals induced by microwaves under the conditions of adding SiC seeds with particle sizes of 0.5 μm, 1 μm, and 5 μm, respectively. Changes in microscopic morphology. Among them, Figure 6a is the SEM photo of the SiC crystal provided in Example 7, Figure 6b is the SEM photo of the SiC crystal provided in Example 8, and Figure 6c is the SEM photo of the SiC crystal provided in Example 4;
从图6可以看出在以400W/min升温速率升温至1100℃保温20min的条件下，添加小粒径0.5μm SiC晶种的样品合成出的碳化硅晶体粒径较小，而随着晶种粒度的增大，合成出的碳化硅粉体粒径也随之增大，且轮廓分明，晶体形貌和结构更好。It can be seen from Figure 6 that under the condition of heating up to 1100°C at a heating rate of 400W/min and holding for 20min, the SiC crystal grain size synthesized by the sample with a small particle size of 0.5μm SiC seed crystal is smaller, and the SiC crystal grain size is smaller as the seed crystal As the particle size increases, the particle size of the synthesized silicon carbide powder also increases, and the outline is clear, and the crystal morphology and structure are better.
综上，本发明采用SiC晶种诱导微波合成SiC的过程中，SiC作为良好的微波吸收体材料，SiC晶种与微波耦合产生热量，低温下促进原料反应；高温下SiC晶种可以作为析晶平台，促进晶体形核与生长；因此在微波加热过程中，SiC晶种既可使自身成为局部热点促进原料反应，又可作为晶体生长热台，诱导合成SiC形核与原位生长。相比于工业上现用的晶种诱导技术，本文工艺将极大的降低SiC晶体合成的难度和工艺条件；微波加晶种复合诱导合成SiC具有良好的应用前景。In summary, in the process of using SiC seed crystals to induce microwave synthesis of SiC in the present invention, SiC is used as a good microwave absorber material, and SiC seed crystals are coupled with microwaves to generate heat, which promotes the reaction of raw materials at low temperatures; SiC seed crystals can be used as crystallization at high temperatures. Therefore, during the microwave heating process, the SiC seed crystal can not only make itself a local hot spot to promote the reaction of raw materials, but also serve as a crystal growth hot platform to induce the synthesis of SiC nucleation and in-situ growth. Compared with the current industrial seed crystal induction technology, the process in this paper will greatly reduce the difficulty and process conditions of SiC crystal synthesis; microwave plus seed crystal composite induction synthesis of SiC has a good application prospect.
本发明描述了优选实施例及其效果。但本领域内的技术人员一旦得知了基本创造性概念，则可对这些实施例作出另外的变更和修改。所以，所附权利要求意欲解释为包括优选实施例以及落入本发明范围的所有变更和修改。The present invention describes preferred embodiments and their effects. However, those skilled in the art can make additional changes and modifications to these embodiments once the basic inventive concept is known. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention.
尽管已经示出和描述了本发明的实施例，对于本领域的普通技术人员而言，可以理解在不脱离本发明的原理和精神的情况下可以对这些实施例进行多种变化、修改、替换和变型，本发明的范围由所附权利要求及其等同物限定。Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (9)

  1. 一种晶种诱导微波合成SiC晶体的制备方法，其特征在于，包括以下步骤：A method for preparing SiC crystals synthesized by seed crystal induced microwave, characterized in that it comprises the following steps:
    将硅粉、纳米碳黑及SiC晶种均匀混合后，获得混合粉体，再将混合粉体压制成坯体，随后采用微波加热，于800～1100℃保温15～30min合成SiC晶体，即得所述晶种诱导微波合成SiC晶体。After uniformly mixing silicon powder, nano-carbon black and SiC seed crystals, the mixed powder is obtained, and then the mixed powder is pressed into a green body, and then heated by microwaves, and kept at 800-1100°C for 15-30 minutes to synthesize SiC crystals. The seed crystal induces microwave synthesis of SiC crystals.
  2. 根据权利要求1所述的晶种诱导微波合成SiC晶体的制备方法，其特征在于，所述微波加热过程中，功率的输入速率为200～600W/min。The method for preparing SiC crystals synthesized by seed crystals induced by microwaves according to claim 1, characterized in that, during the microwave heating process, the power input rate is 200-600 W/min.
  3. 根据权利要求1所述的晶种诱导微波合成SiC晶体的制备方法，其特征在于，所述SiC晶种粒径为0.5～5μm，其加入量为原料总质量的1～20wt％。The method for preparing SiC crystals synthesized by seed crystals induced by microwaves according to claim 1, characterized in that, the particle size of the SiC seed crystals is 0.5-5 μm, and the added amount thereof is 1-20 wt% of the total mass of raw materials.
  4. 根据权利要求1所述的晶种诱导微波合成SiC晶体的制备方法，其特征在于，所述硅粉与纳米碳黑摩尔比为1：1～3。The method for preparing SiC crystals synthesized by seed crystals induced by microwaves according to claim 1, characterized in that the molar ratio of silicon powder to nano-carbon black is 1:1-3.
  5. 根据权利要求1所述的晶种诱导微波合成SiC晶体的制备方法，其特征在于，所述混合粉体是将硅粉、纳米碳黑及SiC晶种以无水乙醇作为分散介质采用球磨法进行混料，转速设置为100r/min球磨12h，然后以80℃的温度真空干燥12h，即得。The method for preparing SiC crystals synthesized by seed crystals induced by microwaves according to claim 1, wherein the mixed powder is carried out by ball milling silicon powder, nano-carbon black and SiC seeds with absolute ethanol as a dispersion medium Mix the materials, set the rotational speed at 100r/min and ball mill for 12h, then vacuum dry at 80°C for 12h to obtain the product.
  6. 根据权利要求5所述的晶种诱导微波合成SiC晶体的制备方法，其特征在于，所述混合粉体的粒径≥60目。The method for preparing SiC crystals synthesized by seed crystals induced by microwaves according to claim 5, characterized in that the particle size of the mixed powder is ≥60 mesh.
  7. 根据权利要求1所述的晶种诱导微波合成SiC晶体的制备方法，其特征在于，坯体加热时，将坯体放入氧化铝坩埚内，并在其四周覆盖石英砂粉末；再将坩埚放入具有氧化铝保温箱和莫来石保温纤维棉构成的保温结构中，进行微波加热。The method for preparing SiC crystals synthesized by seed crystal induction microwave according to claim 1 is characterized in that, when the green body is heated, the green body is put into an alumina crucible and covered with quartz sand powder around it; then the crucible is placed Put it into the insulation structure composed of alumina insulation box and mullite insulation fiber cotton, and carry out microwave heating.
  8. 一种权利要求1～7任一项所述的制备方法制得的晶种诱导微波合成的SiC晶体。A SiC crystal obtained by the preparation method described in any one of claims 1 to 7 through seed crystal induction microwave synthesis.
  9. 权利要求8所述的SiC晶体在电子器件半导体和换热器中的应用。Application of the SiC crystal described in claim 8 in electronic device semiconductors and heat exchangers.
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