Giant dielectric ceramic capacitor medium as well as preparation method thereof

Abstract

The invention relates to the technical field of inorganic nonmetal materials and particularly relates to a ceramic capacitor medium with a small giant dielectric capacitance temperature change rate as well as a preparation method thereof. A formula composition of the ceramic capacitor medium comprises the following components: 91wt%-98wt% of Ca0.925Nd0.05Cu3Ti4O12, 0.1wt%-8.0wt% of (Ba0.65Sr0.35)TiO3, 0.1wt%-4wt% of MgO and 0.01wt%-1.8wt% of Cr2O3, wherein the Ca0.925Nd0.05Cu3Ti4O12 and the (Ba0.65Sr0.35)TiO3 are respectively synthesized by adopting conventional chemical materials through a solid-phase method. According to the ceramic capacitor medium and the preparation method thereof disclosed by the invention, the ceramic capacitor medium with the small giant dielectric capacitance temperature change rate, which is lead-free and cadmium-free, is prepared by adopting common chemical materials, namely capacitor ceramic; a sintering temperature of the capacitor ceramic further can be lowered; the medium is suitable for preparing a monolithic ceramic capacitor and a single-layer ceramic chip capacitor.

Description

technical field [0001] The invention relates to the technical field of inorganic non-metallic materials, in particular to a ceramic capacitor medium with a small temperature change rate of giant dielectric capacitance and a preparation method thereof; it adopts common chemical raw materials of capacitor ceramics to prepare a lead-free and cadmium-free giant dielectric capacitance temperature The ceramic capacitor medium with a small change rate can also reduce the sintering temperature of the capacitor ceramic. This medium is suitable for the preparation of monolithic ceramic capacitors and single-layer chip ceramic capacitors, which can greatly reduce the cost of ceramic capacitors. The dielectric constant of this medium is extremely high. It is easy to realize the miniaturization of the ceramic capacitor, and at the same time, the withstand voltage can be increased to expand the application range of the ceramic capacitor, and the environment is not polluted in the process of ...

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Problems solved by technology

CCTO ceramics, regardless of single crystal or polycrystalline form, exhibit an unusually high dielectric constant, and have received more and more attention in recent years; CCTO ceramics have many advantages, such as a very large dielectric constant (εr is 10 4 ), in a relatively wide frequency range and a relatively wide temperature range, the dielectric constant changes little with frequency and temperature, and the preparation process is quite simple, and the dielectric constant can be adjusted by changing the sintering conditions. In the resonator , filter, memory and other important electronic devices have great application potential, so it is particularly attractive; however, the dielectric loss (tanδ value) of the usually prepared CCTO ceramics is very large, which will lead to the failure of the device or circuit in practical applications. Problems such as heat generation, unstable work, or signal attenuation are not conducive to its application as an electronic material; in order to solve the problem of large dielectric loss of CCTO ceramics, researchers have made many attempts to dope or replace the ceramics. These attempts The results were not very successful, and finally no modified CCTO ceramics with comprehensive dielectric performance indicators meeting the requirements of practical applications were obtained; specifically, these attempts either failed to achieve the purpose of reducing the dielectric loss to a sufficient extent, or obviously damaged the original properties of CCTO ceramics. The characteristic of high dielectric constant leads to a very low dielectric constant after modification, or destroys the original low-frequency dielectric constant of CCTO ceramics, which basically does not change with frequency; It is an important research topic that the advantage of high dielectric constant can significantly reduce the effective method of dielectric loss.

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