Lead-free high-voltage capacitor dielectric ceramic sintered at medium temperature and preparation method thereof

Abstract

The invention discloses lead-free high-voltage capacitor dielectric ceramic sintered at medium temperature and a preparation method thereof; the lead-free high-voltage capacitor dielectric ceramic is prepared from, by weight, 100 parts of Sr0.78Ca0.20Ba0.02TiO3, 8-20 parts of Bi2O3.2TiO2, 0.05-0.35 part of MnCO3, 0.05-0.30 part of Co2O3, 0.01-0.08 part of MgTiO3, 0-0.20 part of Al2O3, 0-0.10 PART OF Nb2O5, 0-0.08 part of HfO2, and 1-2 parts of a sintering aid, via the steps of ball milling, drying, grinding and screening. The dielectric constant and insulating resistance of the capacitor dielectric ceramic are adjusted mainly by changing the content of Bi2O3.2TiO2, comprehensive performance of the dielectric ceramic is improved by selecting different doping modifying elements, and the finally prepared dielectric ceramic has high dielectric constant, low loss, high insulating resistance and high breakdown strength. The dielectric ceramic is sintered at medium temperature and free of lead, is suitable for the preparation of high-voltage multilayer ceramic capacitors (MLCC), and has great practical value and market value.

Description

technical field [0001] The invention relates to the technical field of electronic information materials and components, in particular to a medium-temperature sintered lead-free high-voltage capacitor dielectric ceramic material and a preparation method. The cost of ceramic capacitors is suitable for the development of single-layer and multi-layer ceramic capacitors. Background technique [0002] High-voltage ceramic capacitors have the advantages of high breakdown voltage, large capacity, high stability, high energy storage, AC high frequency, etc., and have the function of blocking DC and separating various frequency components. It is one of the key components of high-voltage power supplies and high-voltage lines such as voltage doubling power circuits for machines and various testing instruments, AC circuit breakers, etc. It is widely used in power equipment for power transmission and distribution systems and equipment for processing pulse energy. [0003] With the advanc...

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Problems solved by technology

Generally, barium titanate ceramics have the characteristics of high dielectric constant, large dielectric loss (1% to 2%) and low breakdown voltage (<100kV / cm) due to their ferroelectric structure. In addition, there is electrostriction. phenomenon, thus limiting its application in the field of high voltage capacitors

Another available high-voltage capacitor material is titanium dioxide, which has a high breakdown voltage (≈350kV / cm), low dielectric loss (≈0.05%) but low dielectric constant (≈110), so it is used as a high-voltage energy storage dielectric ceramic Its dielectric constant is low

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