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A preparation method of large flow capacity and low residual pressure varistor ceramics for UHV power transmission system

A technology of power transmission system and varistor ceramics, applied in piezoelectric/electrostrictive/magnetostrictive devices, circuits, electrical components, etc. complication and other problems, to achieve the effect of eliminating unstable aging performance, increasing nonlinear coefficient, and stable V-I characteristics

Active Publication Date: 2018-05-18
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In actual industrial production, Al ions are mostly used as donor ions to be added to ZnO varistor materials, but the addition of Al ions is often accompanied by an increase in leakage current, and at the same time leads to a decrease in the nonlinear coefficient, and the aging characteristics of ZnO varistors also become unstable
In industrial applications, there is also a method of pre-sintering ZnO and some auxiliary additives, so that part of the mixed raw materials are pre-reacted to improve the barrier and stability of the pressure-sensitive material. This method complicates the production process
At present, mainly by improving the uniformity of the crystal grains, the current can evenly flow through the entire varistor valve, thereby increasing the flow capacity of the ZnO varistor, but the uniformity of the grains is affected by the sintering process and the mixing and grinding process of raw materials, etc. The impact is greater, and it is more difficult to achieve uniformity of grains

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] According to the preparation method of a large flow capacity and low residual voltage varistor ceramics introduced in the patent specification of the present invention, the actual preparation of high-performance ZnO varistor ceramics is carried out.

[0041] (1) Raw material preparation:

[0042] According to the following ratio ZnO (87.5%), Bi 2 o 3 (2.0mol%), Sb 2 o 3 (1.5mol%), MnO 2 (1.0mol%), Cr 2 o 3 (1.0mol%), Co 2 o 3 (1.5mol%), SiO 2 (2.0mol%), and Ag 2 O(1.0mol%), Ga(NO 3 ) 3 (1.0mol%), Al(NO 3 ) 3 (1.5 mol%) to prepare the starting material.

[0043] (2) Slurry preparation

[0044] 1) Auxiliary additives for ball milling:

[0045] Bi 2 o 3 (2.0mol%), Sb 2 o 3 (1.5mol%), MnO 2 (1.0mol%), Cr 2 o 3 (1.0mol%), Co 2 o 3 (1.5mol%), SiO 2 (2.0 mol%) was put into the ball mill jar of star type ball mill, added appropriate amount of deionized water, and ball milled for 8 hours.

[0046] 2) Add (87.5mol%) ZnO to the auxiliary mixing slurry af...

Embodiment 2

[0061] According to the preparation method of a large flow capacity and low residual voltage varistor ceramics introduced in the patent specification of the present invention, the actual preparation of high-performance ZnO varistor ceramics is carried out.

[0062] (1) Raw material preparation:

[0063] According to the following ratio ZnO (95.8mol%), Bi 2 o 3 (0.5mol%), Sb 2 o 3 (0.5mol%), MnO 2 (0.5mol%), Cr 2 o 3 (0.5mol%), Co 2 o 3 (0.5mol%), SiO 2 (1.0mol%), and Ag 2 O(0.1mol%), Ga(NO 3 ) 3 (0.1mol%), Al(NO 3 ) 3 (0.5 mol%) to prepare starting materials.

[0064] (2) Slurry preparation

[0065] 1) Auxiliary additives for ball milling:

[0066] Bi 2 o 3 (0.5mol%), Sb 2 o 3 (0.5mol%), MnO 2 (0.5mol%), Cr 2 o 3 (0.5mol%), Co 2 o 3 (0.5mol%), SiO 2 (1.0 mol%) was put into the ball mill jar of the star-type ball mill, added an appropriate amount of deionized water, and ball milled for more than 6 hours.

[0067] 2) Add (87.5-95.8mol%) ZnO to the auxi...

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PUM

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Abstract

The invention provides a preparation method of large-discharge-current-capacity and low-residual-voltage voltage-sensitive ceramic used for an ultrahigh voltage power transmission system. The ceramic is prepared from zinc oxide ZnO, bismuth oxide Bi2O3, antimonous oxide Sb2O3, manganese dioxide MnO2, chromic oxide Cr2O3, cobalt oxide Co2O3, silicon dioxide SiO2, silver oxide Ag2O, Ga(NO3)3 and aluminium nitrate Al(NO3)3. The method has the advantages that the leakage current is restrained, the ageing performance of a ZnO voltage-sensitive resistor manufactured according to the formula is more stable by adding elements Al and Ga together, and the defect that when only Ag ions are added, the ageing performance of the voltage-sensitive resistor is not stable is overcome.

Description

technical field [0001] The invention relates to the field of material chemistry, in particular to a method for preparing ceramics. Background technique [0002] ZnO varistors are made of ZnO as the main raw material, adding a small amount of Bi2O3, Sb2O3, MnO2, Cr2O3, Co2O3, and silver glass powder as auxiliary components, and are prepared by ceramic sintering process. Due to its good nonlinear performance and the advantages of large current capacity, since it was discovered in the 1870s, ZnO varistors have been widely used in power system lightning protection and overvoltage protection of power equipment as the core component of power system lightning arresters. [0003] With the continuous improvement of the transmission voltage level, especially in the UHV system, the problem of equipment insulation has become increasingly prominent, and it will pay a high price to comprehensively improve the equipment insulation. The surge arrester assembled with ZnO varistors with high...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L41/187C04B35/453C04B35/626C04B35/64
CPCC04B35/453C04B35/6261C04B35/64C04B2235/3217C04B2235/3241C04B2235/3267C04B2235/3275C04B2235/3286C04B2235/3291C04B2235/3294C04B2235/3298C04B2235/3418C04B2235/96
Inventor 何金良胡军曾嵘
Owner TSINGHUA UNIV
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