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

Abstract

A method for preparing zinc oxide varistor ceramics with large flow capacity, low residual voltage and high gradient, which is characterized in that the formula ingredients include zinc oxide ZnO, bismuth oxide Bi2O3, antimony trioxide Sb2O3, manganese dioxide MnO2, chromium oxide Cr2O3, cobalt trioxide Co2O3, silicon dioxide SiO2, silver nitrate oxide Ag2O, gallium nitrate Ga(NO3)3, yttrium nitrate Y(NO3)3. The beneficial effects are: the leakage current is suppressed; the joint addition of Y and Ga elements makes the aging performance of the ZnO varistor produced by this formula more stable, eliminating the problem that the leakage current cannot be suppressed due to the simple addition of Ag ions. at.

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...

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