Dielectric medium of ceramic capacitor and preparation process thereof

Abstract

The invention discloses a dielectric medium of a ceramic capacitor and a preparation process thereof and belongs to the field of capacitor manufacturing. The dielectric medium comprises the following raw materials in parts by weight: 40-60 parts of BaTiO3, 10-20 parts of SrTiO3, 10-20 parts of BaZrO3, 8-12 parts of CaTiO3, 8-12 parts of MgNb2O5, 2-4 parts of CeO2, 2-4 parts of ZnO, 2-4 parts of Co2O3, 1-3 parts of BaSiO3 and 1-3 parts of Gd2O3. The preparation process comprises the following steps of: crushing the raw materials and uniformly mixing the raw materials; then drying the raw materials and adding an adhesive for granulation to obtain granular materials; and finally, pressing the granular materials into a raw blank sheet and sintering the same to obtain the dielectric medium. The dielectric medium of the ceramic capacitor provided by the invention is high in electric constant and high in withstand voltage, and free of environmental pollution in a using process. The invention aims to provide a preparation method of the dielectric medium of the ceramic capacitor. The preparation method is relatively low in cost and free of pollution- to the environment in the preparation process.

Description

technical field [0001] The invention belongs to the field of capacitor manufacturing, and in particular relates to a dielectric of a ceramic capacitor and a preparation process thereof. Background technique [0002] Color TV, computer, communication, aerospace, missile, navigation and other fields urgently need ceramic capacitors with high breakdown voltage, good temperature stability, high reliability, miniaturization and large capacity. In order to realize the miniaturization and large capacity of ceramic capacitors, the dielectric of ceramic capacitors is required to have a high dielectric constant; in order to achieve a high breakdown voltage of ceramic capacitors, the dielectric withstand voltage of ceramic capacitors is required to be high; at the same time, with people's health and The increasing attention to environmental protection requires that the dielectric of ceramic capacitors will not cause harm to the human body and the environment during the process of prepa...

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Problems solved by technology

Another example is the Chinese Invention Patent Application Publication Note CN1212443A (the name of the invention is "high dielectric high performance medium temperature sintered chip type multilayer ceramic capacitor ceramic material", the patent application number is 97117286.2), although the disclosed ceramic capacitor ceramic material has a dielectric constant High (dielectric constant ≥ 16000), but poor withstand voltage (withstand voltage 700V / mm), and its components contain a certain amount of lead

Also have, Chinese invention patent application public specification CN1212444A (invention name is " high-performance mid-temperature sintered chip type multilayer ceramic dielectric capacitor ceramic material ", and the patent application number is 97117287.0), the disclosed capacitor ceramic material dielectric constant is too small (dielectric The electric constant is 3000), the dielectric loss is less than 1.5%, and the withstand voltage is low (the withstand voltage is 860V / mm), and its components contain a certain amount of lead

[0004] Although the dielectric of some ceramic capacitors does not contain lead, it is less harmful to the human body and the environment during the production, use and disposal of ceramic capacitors, but its dielectric constant is too small and / or the withstand voltage is low

For example, Chinese journal "Electronic Components and Materials" No. 5, 1989, disclosed a high-voltage ceramic capacitor dielectric material in the article "High Dielectric and High Voltage 2B4 Dielectric Ceramics". The dielectric constant of this dielectric material is too small (dielectric constant ε=2500-2600), tgδ=0.5-1.4%, poor pressure resistance (DC withstand voltage strength is 7KV / mm)

Another example is the Chinese Invention Patent Application Publication Specification CN1306288A (the name of the invention is "a high-voltage ceramic capacitor dielectric", and the patent application number is 00112050.6). Although the disclosed capacitor ceramic dielectric is a lead-free dielectric material, its DC withstand voltage can reach 10kV / mm Above, but the dielectric constant is too small (dielectric constant is 1860-3300), and the sintering temperature is higher (sintering temperature is 1260-1400°C)

In addition, the Chinese invention patent application publication specification CN1619726A (invention name is "a medium-low temperature sintered high-voltage ceramic capacitor medium", the patent application number is 200410041863.x), the weight percentage content of each component is: BaTiO 3 60-90%, SrTiO 3 1-20%, CaZrO 3 0.1-10%, Nb 2 o 5 0.01-1%, MgO0.01-1%, CeO 2 0.01-0.8%, ZnO0.01-0.6%, Co 2 o 3 0.03-1%, bismuth-lithium solid solution 0.05-10%, the dielectric constant is 2000-3000, the withstand voltage is above 6kV / mm, the dielectric constant and withstand voltage are still not ideal

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