A large flow capacity, low residual voltage, high gradient zinc oxide varistor ceramics

A varistor, zinc oxide technology, applied in the direction of piezoelectric/electrostrictive/magnetostrictive devices, circuits, electrical components, etc., can solve the problem of unstable aging characteristics of ZnO varistors, reduction of non-linear coefficients, production process Complications and other problems, to achieve the effect of stable V-I characteristics, increase of nonlinear coefficient, and elimination of leakage current

Active Publication Date: 2018-09-14
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

[0042] According to the preparation method of ZnO varistor ceramics with large flow capacity and low residual voltage introduced in the patent specification of the present invention, the actual preparation of high-performance ZnO varistor ceramics is carried out.

[0043] (1) Raw material preparation:

[0044] 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%), Y(NO 3 ) 3 (1.5 mol%) to prepare the starting material.

[0045] (2) Slurry preparation

[0046] 1) Auxiliary additives for ball milling:

[0047] 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.

[0048] 2) Add (87.5mol%) ZnO to the auxiliary mixing slu...

Embodiment 2

[0063] According to the preparation method of ZnO varistor ceramics with large flow capacity and low residual voltage introduced in the patent specification of the present invention, the actual preparation of high-performance ZnO varistor ceramics is carried out.

[0064] (1) Raw material preparation:

[0065] 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%), Y(NO 3 ) 3 (0.5 mol%) to prepare starting materials.

[0066] (2) Slurry preparation

[0067] 1) Auxiliary additives for ball milling:

[0068] 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.

[0069] 2) Add (87.5-95.8mol%) ZnO to th...

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PUM

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Abstract

The invention relates to a large-discharge-current-capacity low-residual-voltage high-gradient zinc oxide piezoresistor ceramic. The invention is characterized in that the ceramic comprises the following formula components: zinc oxide ZnO, bismuth oxide Bi2O3, antimony trioxide Sb2O3, manganese peroxide MnO2, chromic oxide Cr2O3, cobaltic oxide Co2O3, silicon dioxide SiO2, silver oxide Ag2O, gallium nitrate Ga(NO3)3 and yttrium nitrate Y(NO3)3. By using the ceramic, the leakage current is inhibited; and by adding the Y and Ga elements, the ZnO piezoresistor prepared according to the formula has more stable aging resistance, thereby overcoming the defect that the leakage current can not be inhibited when the single Ag ions are added.

Description

technical field [0001] The invention relates to the field of material chemistry, in particular to a ceramic and a preparation method thereof. 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, ZnO varistors have been widely used in lightning protection of power systems and overvoltage protection of power equipment since they were discovered in the 1870s as the core components of power system 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 w...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L41/187C04B35/453C04B35/622
CPCC04B35/453C04B35/622C04B2235/3225C04B2235/3241C04B2235/3267C04B2235/3275C04B2235/3286C04B2235/3291C04B2235/3294C04B2235/3298C04B2235/3418C04B2235/602C04B2235/656C04B2235/96
Inventor 何金良胡军
Owner TSINGHUA UNIV
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