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Liquid-phase sintered SiC non-linear resistance ceramic and preparation method thereof

A non-linear resistance and ceramic preparation technology, applied in the field of SiC ceramics, can solve problems such as component failure, current and energy distribution differences, and achieve the effect of improving strength and toughness

Active Publication Date: 2017-05-17
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For ZnO nonlinear components, such as direct parallel connection, although under the condition of small voltage changes, it will cause unacceptable large differences in current and energy distribution, and in extreme cases, the components will fail due to overheating

Method used

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  • Liquid-phase sintered SiC non-linear resistance ceramic and preparation method thereof
  • Liquid-phase sintered SiC non-linear resistance ceramic and preparation method thereof
  • Liquid-phase sintered SiC non-linear resistance ceramic and preparation method thereof

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preparation example Construction

[0028] Preparation of slurry. SiC powder, Al 2 o 3 Powder and Y 2 o 3 The powder is used as a raw material to prepare a slurry. The Al 2 o 3 The particle size of the powder is less than 1 μm, the Y 2 o 3 The particle size of the powder is less than 1 μm, which is conducive to the formation of low melting point eutectic compounds. The slurry also contains a binder, which is added in an amount of 2wt% to 5wt% of the powder mass (the total mass of SiC and sintering aids), and organic substances such as PVA and PVB can also be formulated into a solution as required. As an example, SiC powder, sintering aid (Al 2 o 3 Powder and Y 2 o 3 Powder) and binder are prepared into a 40-45wt% slurry (the solvent of the slurry can be deionized water, ethanol, etc.), using SiC balls as grinding balls, powder: SiC balls = 1:2 (mass ), mixed for 24 hours to obtain the slurry. The solid content of the slurry prepared in the present invention is 40-45wt%. If the solid content is high...

Embodiment 1

[0040] To make Al 2 o 3 and Y 2 o 3 Mix evenly, the mass ratio Al 2 o 3 : Y 2 o 3 = 3:2 Al 2 o 3 and Y 2 o 3 The mixed powder is made into a 40wt% slurry (the solvent is deionized water), using SiC balls as grinding balls, powder: SiC balls = 1:2 (mass), mixed for 24 hours, then dried and sieved to obtain the required sintering aids;

[0041] SiC powder, sintering aid Al 2 o 3 and Y 2 o 3 Powder mixture (mass ratio Al 2 o 3 : Y 2 o 3 =3:2, 4wt%) 100g in total, PVA is 2wt% of the powder (SiC and sintering aid), the powder is made into a slurry with a solid content of 45wt% (the solvent is deionized water), and the SiC ball 200g is ball milling medium, mixed for 24h. Then spray granulation, and the obtained powder is molded under a pressure of 16MPa on a flat vulcanizer, and then isostatically pressed under a pressure of 200MPa. After debonding, it was sintered under normal pressure Ar gas atmosphere, the sintering temperature was 1900°C, and the holding tim...

Embodiment 2

[0043] SiC powder, sintering aid Al 2 o 3 and Y 2 o 3 Powder mixture (mass ratio Al 2 o 3 : Y 2 o 3 =3:2, 6wt%) 100g in total, PVA is 2wt% of the powder, the powder is made into a slurry with a solid content of 45wt% (the solvent is deionized water), and 200g of SiC balls are used as the ball milling medium, and mixed for 24h . Then spray granulation, and the obtained powder is molded under a pressure of 16MPa on a flat vulcanizer, and then isostatically pressed under a pressure of 200MPa. After debonding, it was sintered under normal pressure Ar gas atmosphere, the sintering temperature was 1900°C, and the holding time was 1h. The obtained SiC non-linear resistor ceramic had a density of 3.16gcm -3 , the bending strength is 605MPa, the fracture toughness is 7.2MPam 1 / 2 . The obtained SiC non-linear resistor ceramics were made into small discs of Φ12mm and thickness 2mm, and silver paste electrodes were coated on both ends, and then kept in a muffle furnace at 750°C ...

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Abstract

The invention relates to a liquid-phase sintered SiC non-linear resistance ceramic and a preparation method thereof. The preparation method comprises the following steps: by taking SiC powder, Al2O3 powder and Y2O3 powder as raw materials, preparing so as to obtain slurry, wherein the particle size of the Al2O3 powder is smaller than 1[mu] m, and the particle size of the Y2O3 powder is smaller than 1[mu] m; performing spray granulation on the obtained slurry, and molding so as to obtain a blank; and performing vacuum unsticking on the obtained blank, and sintering for 1-2 hours at 1800-2000 DEG C in a normal-pressure insert atmosphere, thereby obtaining the SiC non-linear resistance ceramic. According to the SiC non-linear resistance ceramic prepared by using a liquid-phase sintering method, as eutecticevaporate rare-earth oxide sintering aids (the particle sizes of the Al2O3 powder and the Y2O3 powder are both smaller than 1[mu] m) are introduced, densification of the SiC ceramic sintered at relatively low temperature can be achieved.

Description

technical field [0001] The invention relates to a preparation method of SiC non-linear resistance ceramics applicable to surge voltage absorbing elements and demagnetization resistors of protection circuits, belonging to the field of SiC ceramics. Background technique [0002] In the generator set excitation system of a large hydropower or thermal power station, when a failure occurs inside the generator set or at the outlet of the generator or when the generator stops normally, the excitation power supply must be cut off quickly. Since the generator rotor winding is a large inductance for energy storage, the excitation The sudden change of current will inevitably cause a considerable transient overvoltage at both ends of the rotor winding, resulting in breakdown of the rotor insulation, so the magnetic energy in the rotor inductance must be consumed as soon as possible. Silicon carbide (SiC) material is called the basic material of "extreme electronic devices" by the indust...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/565C04B35/64
CPCC04B35/565C04B35/64C04B2235/48C04B2235/77C04B2235/96
Inventor 陈健黄政仁陈军军殷杰
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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