Low-dielectric-constant microwave dielectric ceramic CaLi3NdV8O24 and preparation method thereof

Abstract

The invention discloses high-quality-factor temperature-stable low-dielectric-constant microwave dielectric ceramic CaLi3NdV8O24 capable of being sintered at low temperature, and a preparation method thereof. The preparation method comprises the following steps: (1) weighing and burdening original powder, having the purity over 99.9% (by weight), of CaCO3, Li2CO3, Nd2O3 and V2O5 according to the constitution of CaLi3NdV8O24; (2) carrying out wet ball-grinding and mixing on the raw materials in the step (1) for 12 hours, wherein a ball grinding medium is distilled water, drying and then pre-sintering for 6 hours at an air atmosphere at 700 DEG C; (3) adding a binder to the powder obtained in the step (2), granulating, then carrying out compression moulding, and finally sintering for 4 hours at an air atmosphere of 750-800 DEG C; a polyvinyl alcohol solution having the mass concentration of 5% is adopted as the binder, and the addition amount of the polyvinyl alcohol accounts for 3% of the total mass of the powder. The ceramic prepared by using the preparation method can be favorably sintered below 800 DEG C, wherein the dielectric constant reaches 20.6-21.4, the quality factor QF is up to 91000-126000GHz, and the temperature coefficient of resonance frequency is low; the microwave dielectric ceramic CaLi3NdV8O24 has a great application value in the industry.

Description

technical field [0001] The invention relates to a dielectric ceramic material, in particular to a dielectric ceramic material for manufacturing microwave components such as ceramic substrates, resonators and filters used in microwave frequencies and a preparation method thereof. Background technique [0002] Microwave dielectric ceramics refer to ceramics that are used as dielectric materials in circuits in the microwave frequency band (mainly UHF and SHF bands) and perform one or more functions. They are widely used as resonators, filters, and dielectric substrates in modern communications. Components such as chips and dielectric waveguide circuits are the key basic materials of modern communication technology. They have been used in portable mobile phones, car phones, cordless phones, TV satellite receivers and military radars. They are used in modern communication tools. It is playing an increasingly important role in the process of miniaturization and integration. [00...

AI Technical Summary

Problems solved by technology

[0009] In the process of exploring and developing new low-firing microwave dielectric ceramic materials, material systems such as Li-based compounds, Bi-based compounds, tungstate compounds and tellurate-based compounds with inherently low sintering temperatures have received extensive attention and research. However, due to the three performance indicators of microwave dielectric ceramics (ε r with Q f and τ ? ) is a mutual restrictive relationship (see literature: The restrictive relationship between the dielectric properties of microwave dielectric ceramic materials, Zhu Jianhua, Liang Fei, Wang Xiaohong, Lu Wenzhong, Electronic Components and Materials, Issue 3, March 2005), satisfying three There are very few single-phase microwave dielectric ceramics that require high performance and can be sintered at low temperature, mainly because their resonant frequency temperature coefficient is usually too large or the quality factor is too low to meet the practical application requirements.

At present, most of the research on microwave dielectric ceramics is a summary of experience obtained through a large number of experiments, but there is no complete theory to explain the r

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