High-quality-factor temperature-stable type microwave dielectric ceramic CaLi4Ge2O7 and preparation method thereof

Abstract

The invention discloses a high-quality-factor temperature-stable type ultralow-dielectric-constant microwave dielectric ceramic CaLi4Ge2O7 and a preparation method thereof. The preparation method comprises the steps: (1) weighing and burdening CaCO3, Li2CO3 and GeO2 original powders with the purity of more than or equal to 99.9 wt% according to the composition of CaLi4Ge2O7; (2) carrying out wet ball-milling mixing of the raw materials of the step (1) for 12 h with a ball-milling medium of distilled water, drying, and then pre-sintering for 6 h in an 800 DEG C air atmosphere; and (3) adding a binder to the powder obtained in the step (2), granulating, then pressing and molding, and finally sintering for 4 h in an 850-900 DEG C air atmosphere, wherein the binder adopts a polyvinyl alcohol solution with the mass concentration of 5% and the adding amount of polyvinyl alcohol accounts for 3% of the total mass of the powder. The prepared ceramic is well sintered at the temperature of 900 DEG C or less, has the dielectric constant reaching 13.0-13.9, has the quality factor Qf value as high as 91000-134000 GHz, has small resonant frequency temperature coefficient, and has great application value in industries.

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 mutually 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 relationship between microstructure and dielectric properties. Predict the microwave dielectric properties such as its resonant frequency temperature coefficient and quality factor, which largely limits the development of low temperature co-firing technology and microwave multilayer devices

Exploring and developing microwave dielectric ceramics that can be sintered at low temperature and have near-zero resonant frequency temperature coefficient (-10ppm / ℃≤τ?≤+10ppm / ℃) and high quality factor is the technology in this field A difficult problem that people have always wanted to solve but have never been able to succeed in

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