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Low-resistivity silicon carbide ceramic and preparation method thereof

A technology of silicon carbide ceramics and low resistivity, applied in the field of SiC ceramics, can solve problems such as short service life, performance change, uncontrollable volume, etc.

Inactive Publication Date: 2015-04-01
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Abstract
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Problems solved by technology

Compared with the resistors used in high-power pulse systems, the current domestic solutions for high-voltage, high-current, non-inductive, and instantaneous discharge mainly include metal multi-wound resistors, film resistors, and all-metal oxide components. Among the metal multi-wound resistors, the double-wound wire can effectively reduce the inductance, but if it encounters a strong current and a rapid impact, it will cause the winding to be burned. If a multi-wound resistor is used, the volume cannot be controlled. Inconvenient to use; film resistance can cope with the rapid impact of strong current, but the cost is high, and the service life is short, it may be broken down by strong current after long-term use, and there is still a lot of inductance; all metal oxide group The maximum unit heat capacity of zinc oxide resistance is 800J / cm -3 Around, the temperature coefficient is 2-7×10 -2 / °C, which is far from the requirements of high-power pulse system with energy above kilojoules and low temperature coefficient
In countries such as the United States and Europe, zinc oxide ceramic resistors are mainly used to solve resistance solutions under high voltage, high current, non-inductance, and instantaneous discharge conditions, which are mainly sintered from clay containing zinc oxide, and there are more carbon in them. It is easy to change its properties under high temperature conditions, resulting in changes in performance, so it cannot be used safely for a long time and needs to be replaced regularly
At present, there is no report on the use of pure resistance devices in high-power pulse systems in China, but the international use of pure resistance devices in high-power pulse systems is kept secret

Method used

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  • Low-resistivity silicon carbide ceramic and preparation method thereof

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preparation example Construction

[0021] The invention provides a method for preparing low-resistivity silicon carbide (SiC) ceramics. It includes the following steps:

[0022] 1) SiC powder, AlN powder, B 4 C powder and phenolic resin as raw materials;

[0023] 2) making the raw materials into a slurry with a solid content of 40-45wt%, and performing ball milling and mixing;

[0024] 3) Spray granulation of the slurry mixed by the ball mill, and dry press molding and isostatic pressing molding of the obtained powder;

[0025] 4) After the sample is debonded in vacuum, it is sintered under normal pressure inert atmosphere conditions, the sintering temperature is 1900-2300°C, and the holding time is 1-2h.

[0026] The prepared SiC ceramics have a density of 3.11-3.15 g cm -3 , The bending strength is: 280Mpa-350Mpa, the resistivity is 2330Ω·m~18140Ω·cm.

[0027] SiC powder, AlN powder, B 4 C powder and phenolic resin are raw materials, among which SiC powder is high-purity SiC powder (oxygen content ≤ 1.8...

Embodiment 1

[0039] SiC, AlN (1wt%), sintering aid B 4 C (0.5wt%) and phenolic resin (10wt%) totaled 100g, the powder was made into a slurry with a solid content of 45wt%, and 200g of SiC balls were used as the ball milling medium, mixed for 24h, and then spray granulated to obtain the powder It is formed under 16MPa pressure on a flat vulcanizer, and then isostatically pressed under 200MPa pressure. After debonding, it was sintered under normal pressure Ar gas atmosphere, the sintering temperature was 2200°C, and the holding time was 1h. The obtained SiC ceramics had a density of 3.14gcm -3 , the bending strength is 310MPa, and the resistivity is 2330Ω·cm.

Embodiment 2

[0041] SiC, AlN (5wt%), sintering aid B 4 C (0.6wt%), phenolic resin (10wt%) a total of 100g powder is made into a slurry with a solid content of 45wt%, with 200g of SiC balls as the ball milling medium, mixed for 24h, and then spray granulated, the obtained powder was in Forming under 16Mpa pressure on a flat vulcanizing machine, and then isostatic pressing under 200MPa pressure. After debonding, it was sintered under normal pressure Ar gas atmosphere, the sintering temperature was 2200°C, and the holding time was 1h. The obtained SiC ceramics had a density of 3.11gcm -3 , the bending strength is 350MPa, and the resistivity is 18140Ω·cm.

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Abstract

The invention relates to low-resistivity silicon carbide ceramic and a preparation method thereof. The low-resistivity silicon carbide ceramic comprises SiC, AlN, B4C and C, wherein the content of AlN is 1-5w%, the content of B4C is not more than 1w%, the content of C is 0-3w% and the balance is SiC.

Description

technical field [0001] The invention relates to a method for preparing low-resistivity silicon carbide (SiC) ceramics, belonging to the field of SiC ceramics. Background technique [0002] The principle of the high-power pulse system is: first store the energy obtained from the low-power energy source, and then convert the energy into a high-power pulse through a high-power pulse generator and transmit it to the load. In this system, pure resistive devices are required, and they are required to have the characteristics of high voltage resistance, high current, low distributed inductance, and low capacitance, so as to meet the high stability characteristics of the application. Compared with the resistors used in high-power pulse systems, the current domestic solutions for high-voltage, high-current, non-inductive, and instantaneous discharge mainly include metal multi-wound resistors, film resistors, and all-metal oxide components. Among the metal multi-wound resistors, the ...

Claims

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Application Information

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IPC IPC(8): C04B35/565C04B35/622
Inventor 陈健黄政仁刘学建陈忠明姚秀敏袁明刘岩闫永杰朱云洲刘桂玲张辉
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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