Preparation method of zinc oxide varister

Abstract

The invention relates to a preparation method of a zinc oxide varister, comprising two independent steps: preparing zinc oxide granules with doping ion components; and preparing a sintering material for coating the zinc oxide granules. According to the performance requirement of the varister, the doping components of the zinc oxide granules, the components of the high-impedance sintering material and preparation conditions are prepared in advance; finally, the zinc oxide granules and the high-impedance sintering material are evenly mixed according to a certain proportion, and the zinc oxide varister is prepared according to the conventional technology. The zinc oxide varister prepared by the preparation method not only has voltage-sensitive performance, but also has one or more functions of heat sensitivity, capacitance, inductance, piezoelectricity or magnetic characteristic, and the like, can sinter at low temperature (lower than 900 DEG C) and can use fine silver as an inner electrode.

Description

Technical field [0001] The invention relates to a method for preparing a zinc oxide varistor, in particular to a method for preparing a zinc oxide varistor in which the doping of zinc oxide and the high-resistance sintered material covering zinc oxide crystal grains are divided into two independent processes. Background technique [0002] The zinc oxide varistor (ZnO varistor) is based on zinc oxide, and adds bismuth (Bi), antimony (Sb), silicon (Si), cobalt (Co), manganese (Mn) and chromium (Cr) and other oxides. It is formed after high temperature sintering above 1000℃. Among them, during the high-temperature sintering process, the zinc oxide crystal grains will increase the semiconductivity due to the doping of bismuth (Bi), antimony (Sb), silicon (Si), cobalt (Co), manganese (Mn) and chromium (Cr) plasma. In addition, a high-resistance grain boundary layer with crystalline phase will be formed between zinc oxide crystal grains. [0003] Therefore, in the known preparation met...

AI Technical Summary

Problems solved by technology

[0005] However, in the same sintering process, the zinc oxide varistor preparation method that achieves the doping of zinc oxide grains and the formation of a high-resistance grain boundary layer between the grains has disadvantages in addition to the need for high-temperature sintering to complete the varistor with a crystalline phase. In addition to sintering the high-impedance grain boundary layer, it also brings various limitations to the performance control of zinc oxide varistors.

For example, in the sintering process, the conditions for doping ions in zinc oxide grains are limited, and the type and quantity of doping ions cannot be selected in a wider range. Therefore, the performance of zinc oxide varistors, including breakdown voltage, nonlinear coefficient , C value, leakage current, surge absorption capacity and ESD absorption capacity, etc., cannot be adjusted in a wider range

In the same way, during the sintering process, the conditions for forming a high-impedance grain boundary layer with a crystalline phase between zinc oxide grains are also limited, and in addition to creating more ideal or economical process conditions, it cannot be in a wider range. The composition and dosage of the high-impedance grain boundary layer are selected, so the performance of the zinc oxide varistor cannot be adjusted in a wider range.

Images