Rare earth oxide composite additive for zinc oxide varistor and preparation method thereof

Abstract

The invention relates to a rare earth oxide composite additive for a zinc oxide varistor and a preparation method thereof and belongs to the technical field of varistor material preparation. The preparation method comprises the following steps of: precipitating two or more rare earth element salts, filtering to obtain a precipitate, washing, drying, and calcining to obtain the rare earth oxide composite additive for the zinc oxide varistor. Components of the rare earth oxide composite additive prepared are uniformly mixed. Particle distribution range is narrow. Hydrogen chloride in mother liquor after precipitation can be recovered and reused. There is no discharge of harmful gases such as nitrogen oxide and the like during the calcining process, the whole process is environmentally friendly and has no pollution. In the meanwhile, in comparison with a plurality of rare earth oxide respectively added in a zinc oxide varistor, the rare earth oxide composite additive prepared by the preparation method can be used to make various rare earth elements added to be uniformly distributed, substantially improve the microstructure of the zinc oxide varistor and greatly raise its comprehensive electric properties.

Description

technical field [0001] The invention relates to a rare earth oxide composite additive for zinc oxide varistors and a preparation method thereof, belonging to the technical field of preparation of functional ceramic materials. Background technique [0002] Zinc oxide varistors have been widely used in various high-voltage transmission lines, DC power supply systems and Large grid system. With the rapid development of the above-mentioned various high-voltage engineering systems, higher requirements are put forward for the safety and reliability of related equipment. Therefore, the development of varistor ceramic materials with excellent electrical properties and high reliability has attracted widespread attention. [0003] Zinc oxide varistor ceramics usually add appropriate amount of other metal oxide additives, such as bismuth trioxide, antimony trioxide, cobalt trioxide, manganese dioxide, chromium trioxide, etc., to the zinc oxide base material, and mix them by ball milli...

AI Technical Summary

Problems solved by technology

[0007] At present, the existing methods generally adopt the simultaneous ball milling and mixing of rare earth oxides and zinc oxide base materials and oxides of Bi, Co, Sb, Mn, Cr and other elements to obtain zinc oxide varistor materials. On the one hand, trace amounts of rare earth element additives It is difficult to disperse evenly, which affects the uniformity of the microstructure of the varistor ceramics and the pinning effect of rare earth oxides on the grain boundaries of the varistor ceramics, thereby affecting the potential gradient and comprehensive electrical properties of the varistor ceramics; on the other hand, by adding The nitrates of rare earth elements are then pyrolyzed to obtain rare earth oxide additives. Although the dispersion uniformity of rare earth oxide additives can be improved, harmful substances such as nitrogen oxides will be produced during high-temperature calcination, which will cause serious pollution to the environment.