High purity linear silicon carbide powder and preparation method

A silicon carbide powder, silicon carbide technology, applied in silicon carbide, carbide and other directions, can solve the problems of complex preparation process and consume a lot of energy, and achieve the effects of high product purity, low production cost and short production cycle

Inactive Publication Date: 2012-10-10
HUBEI UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Most of these methods use silicon powder and silicon dioxide powder as the silicon source, graphite, carbon black, and gaseous hydride as the carbon source, and some also use metal as

Method used

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  • High purity linear silicon carbide powder and preparation method
  • High purity linear silicon carbide powder and preparation method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] (1) After mixing 5.0 grams of silica sol and 1.15 grams of graphene oxide evenly, first undergo ultrasonic treatment for 30 minutes at an ultrasonic frequency of 20-120 kHz, and then stir for 3 hours under strong mechanical stirring to obtain a composite precursor; the selected acid The silicon dioxide content in the silica sol is 30%, the pH value is 2.0, and the particle size is 6nm;

[0028] (2) The obtained composite precursor was solidified and dried in a blast drying oven for 48 hours, and then ground by a high-speed ball mill for 2 hours to obtain a fine and homogeneous powder precursor;

[0029] (3) Put the powdery precursor into a high-temperature tube furnace, pass in high-purity argon, and perform a carbothermal reduction reaction at 1500°C for 6 hours; obtain a crude silicon carbide micropowder;

[0030] (4) Soak the crude silicon carbide micropowder in 20% hydrofluoric acid for 2 hours, then filter it with suction, and sinter the filter residue at 400°C for...

Embodiment 2

[0032] (1) After mixing 7.2 grams of silica sol and 1.15 grams of graphene oxide evenly, first undergo ultrasonic treatment for 15 minutes at an ultrasonic frequency of 20 kHz, and then stir for 2 hours under strong mechanical stirring to obtain a composite precursor; the selected acidic silica sol The silica content in the medium is 20%, the pH value is 2.4, and the particle size is 20nm;

[0033] (2) The obtained composite precursor was solidified and dried in a vacuum drying oven for 24 hours, and then ground for 2 hours with a high-speed ball mill to obtain a fine and homogeneous powder precursor;

[0034] (3) Put the powdery precursor into a high-temperature tube furnace, pass in high-purity argon, and perform a carbothermal reduction reaction at 1400°C for 8 hours; obtain a crude silicon carbide micropowder;

[0035] (4) Soak the crude silicon carbide micropowder in 10% hydrofluoric acid for 2 hours, then filter it with suction, and sinter the filter residue at 700°C for...

Embodiment 3

[0037] (1) After mixing 5.0 grams of silica sol and 1.8 grams of graphene oxide evenly, first undergo ultrasonic treatment for 20 minutes at an ultrasonic frequency of 80 kHz, and then stir for 4 hours under strong mechanical stirring to obtain a composite precursor; the selected acidic silica sol The silica content in the medium is 30%, the pH value is 2.0, and the particle size is 6nm;

[0038] (2) The obtained composite precursor was solidified and dried in a blast drying oven for 24 hours, and then ground by a high-speed ball mill for 2 hours to obtain a fine and homogeneous powder precursor;

[0039] (3) Put the powdery precursor into a high-temperature tube furnace, feed high-purity argon, and carry out carbothermal reduction reaction at 1600°C for 2 hours; obtain crude silicon carbide micropowder;

[0040] (4) Soak the obtained silicon carbide micropowder in a mixed acid composed of 10% hydrofluoric acid and 10% nitric acid for 3 hours, then suction filter, and sinter t...

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Abstract

The invention relates to a high purity linear silicon carbide powder and a preparation method, the linear silicon carbide powder product presents light green color and has a cubic crystal system, a microstructure presents a linear state, and the content of the silicon carbide is no less than 99%. The preparation method provided by the present invention comprises the following steps: silica sol and oxidized graphene are uniformly mixed, then subjected to ultrasonic treatment, and completely stirred to obtain a composite precursor. The composite precursor is subjected to solidification, drying and grinding to obtain a powdery precursor with fine and uniform quality. Argon is introduced in the powdery precursor, a carbon thermal reduction is carried out under high temperature in a high temperature tubular furnace to obtain the carbonized silicon powder crude product; the carbonized silicon powder crude product is immersed in inorganic acid and then the pumping filtration is carried out, the unreacted carbon is removed, and cooled to obtain the silicon carbide powder with content of less than 99%. According to the invention, a silicon source is silica sol, a carbon source is oxidized grapheme, the invention has the advantages of no requirement of subsequent processing, no requirement of pressurization, addition of metal catalyst, simple process and short production period; the precursor with homogeneousness is prepared in advance, then the carbon thermal reduction is carried out, the product purity is high, and the method provided by the invention enables large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of ceramic preparation, and in particular relates to a high-purity linear silicon carbide powder and a preparation method thereof. Background technique [0002] Silicon carbide (SiC) material is a new type of semiconductor material developed following the second-generation semiconductor. Its unique wide bandgap (Eg>2.3ev), high thermal conductivity (θ K =4.9W cm -1 K -1 ), high critical breakdown electric field (V=3.0MV cm -1 ), high carrier saturation drift (ζsat=2.0×10 7 cm S -1 ) and other characteristics, it has great application potential in high temperature, high power, high frequency, optoelectronics and radiation resistance. Its special properties of high temperature and radiation resistance are used in fields such as geothermal drilling, petroleum, aerospace, and nuclear energy development; for high frequency and high power, SiC devices are used in radar, communication, and radio and televi...

Claims

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Application Information

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IPC IPC(8): C01B31/36C01B32/97
Inventor 张丹王世敏董兵海卢红兵赵丽许祖勋万丽丁岩峰
Owner HUBEI UNIV
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