Low temperature sintered giant dielectric ceramic capacitor medium and preparation method thereof

Abstract

The invention relates to the technical field of inorganic non-metal materials, and particularly discloses a low temperature sintered ceramic capacitor medium with small giant dielectric capacitance temperature change rate and a preparation method thereof. The medium formula comprises the following components: 88 to 96 wt. % of CaCu3Ti4O12, 0.01 to 7.0 wt.% of (Ba0.65Sr0.35) TiO3, 0.01 to 0.6 wt. % of Nd2O3, 0.1 to 4 wt. % of SiO2-Li2O-B2O3 glass powder, 0 to 0.5 wt. % of MnO2, and 0.5 to 4 wt. % of (Li1 / 2Na1 / 2) NbO3, wherein CaCu3Ti4O12, (Ba0.65Sr0.35) TiO3, (Li1 / 2Na1 / 2) NbO3 and SiO2-Li2O-B2O3 glass powder (SLB) are respectively compounded by conventional chemical raw materials through a solid phase method. According to the invention, common chemical raw materials of capacitor ceramic are adopted to prepare the lead-free and cadmium-free ceramic capacitor medium with small giant dielectric capacitance temperature change rate, the sintering temperature of the capacitor ceramic is greatly reduced, and the medium is applicable to the preparation of monolithic ceramic capacitors.

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 low-temperature sintered giant dielectric capacitance and a preparation method thereof; it adopts common chemical raw materials of capacitor ceramics to prepare lead-free and cadmium-free giant dielectrics The ceramic capacitor medium with a small capacitance temperature change rate can also greatly reduce the sintering temperature of the capacitor ceramic. This medium is suitable for the preparation of monolithic ceramic capacitors and can greatly reduce the cost of ceramic capacitors. The dielectric constant of the medium is extremely high, and it is easy to realize ceramic capacitors. The miniaturization of ceramic capacitors can increase the withstand voltage at the same time to expand the application range of ceramic capacitors, and it does not pollute the environment during preparation ...

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Problems solved by technology

[0002] High dielectric constant provides the possibility for the volume miniaturization of capacitive devices; with the development of electronic device miniaturization, high dielectric constant materials play an increasingly important role in microelectronics technology, copper calcium titanate ( CaCu 3 Ti 4 o 12 , referred to as CCTO) ceramics is one of the most representative high dielectric constant materials, CCTO ceramics show abnormally high dielectric constant regardless of single crystal or polycrystalline form, and have received more and more attention in recent years; CCTO ceramics Has 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; The advantages of high dielectric constant and the effective method of significantly reducing dielectric loss are an important research topic; multilayer ceramic capacitors (MLCC) have the advantages of small size, large capacity, high reliability and high dielectric constant. One of the most widely used electronic components; the cost of MLCC mainly comes from the internal electrode, and its material is mainly palladium or silver-palladium alloy. However, due to the high price of palladium, the research on low-temperature sintering of dielectric ceramics is an important field in this field at home and abroad. One of the hotspots, at present, the sintering temperature of the giant ceramic capacitor dielectric is relatively high, generally 1040-1100 ° C, it is necessary to reduce its sintering temperature to meet the requirements of MLCC

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