Preparation method of zinc oxide varistor ceramics with excellent comprehensive electrical properties

A technology for varistors and electrical performance, applied in electrical components, piezoelectric/electrostrictive/magnetostrictive devices, circuits, etc. Complications and other issues can be eliminated to achieve the effect of eliminating unstable aging performance, increasing nonlinear coefficient, and stabilizing V-I characteristics

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

[0038] (1) Slurry preparation

[0039] Auxiliary additives for ball milling:

[0040] Bi 2 o 3 (1.5mol%), MnO 2 (1mol%), Sb 2 o 3 (1mol%), Co 2 o 3 (1mol%), SiO 2 (1.5mol%) and Cr 2 o 3 (1mol%) was put into a ball mill jar of a star ball mill, an appropriate amount of deionized water was added, and ball milled for 300 min.

[0041] Add 90% mol of ZnO to the auxiliary mixing slurry after ball milling, add PVA, a dispersant and an appropriate amount of deionized water, and mix and ball mill all the mixing materials until they are uniformly dispersed.

[0042] Add aluminum and yttrium ions

[0043] In the uniformly mixed ZnO and auxiliary additives, add Al(NO3) 3 .9H 2 O (2mol%), Y (NO3) 3 .9H 2 O (2mol%), continue ball milling for 60min, after spray granulation, contain water.

[0044] (2) Molding

[0045] The powder obtained in the previous step is sprayed, and after automatically containing water, the tablet molding process is adopted. Using a hydraulic table...

Embodiment 2

[0056] (1) Slurry preparation

[0057] Auxiliary additives for ball milling:

[0058] Bi 2 o 3 (1.55mol%), MnO 2 (0.99mol%), Sb 2 o 3 (0.99mol%), Co 2 o 3 (1.01mol%), SiO 2 (1.48mol%) and Cr 2 o 3 (1mol%) was put into a ball mill jar of a star ball mill, an appropriate amount of deionized water was added, and ball milled for 300 min.

[0059] Add 92% mol of ZnO to the auxiliary mixing slurry after ball milling, add PVA, a dispersant and an appropriate amount of deionized water, and mix and ball mill all the mixing materials until they are uniformly dispersed.

[0060] Add aluminum and yttrium ions

[0061] In the uniformly mixed ZnO and auxiliary additives, add Al(NO3) 3 .9H 2 O (2.6mol%), Y (NO3) 3 .9H 2 O (2.1mol%), continue ball milling for 60min, after spray granulation, contain water.

[0062] (2) Molding

[0063] The powder obtained in the previous step is sprayed, and after automatically containing water, the tablet molding process is adopted. Using a ...

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PUM

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Abstract

The invention relates to a formula of zinc oxide piezoresistor ceramic with a favorable comprehensive electrical performance. The formula is prepared from the following components: ZnO, Bi2O3, MnO2, Sb2O3, Co2O3, SiO2, Al2O3, Y2O3 and Cr2O3. The formula has the beneficial effects that the current leakage is restrained; the aging performance of a ZnO piezoresistor made by the formula is more stable by the jointed addition of Al and Y elements, and the defect that the aging performance of the piezoresistor is instable owing to the pure addition of Al ions is eliminated.

Description

technical field [0001] The invention relates to the field of electrical materials, in particular to a preparation method of varistor ceramics. Background technique [0002] ZnO varistor is made of ZnO as the main raw material, adding a small amount of Bi 2 o 3 , Sb 2 o 3 , MnO 2 、Cr 2 o 3 、Co 2 o 3 , and silver glass powder as auxiliary components, 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 w...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L41/187C04B35/453C04B35/626C04B35/64
CPCC04B35/453C04B35/6261C04B35/64C04B2235/3225C04B2235/3241C04B2235/3262C04B2235/3275C04B2235/3294C04B2235/3298C04B2235/3418C04B2235/656C04B2235/6567
Inventor 何金良胡军
Owner TSINGHUA UNIV
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