Ultra-low dielectric constant microwave dielectric ceramic li2zn3si2o8 and its preparation method

Abstract

The invention discloses temperature-stable type ultralow-dielectric-constant dielectric ceramic Li2Zn3Si2O8 and a preparation method thereof. The preparation method comprises: (1) weighing original powders of Li2CO3, ZnO and SiO2 with the purity of 99.9 wt% or more according to the formula of Li2Zn3Si2O8 and proportioning; (2) performing wet-type ball milling mixing on the raw materials of the step (1) for 12 h by selecting distilled water as a ball milling medium, baking and pre-burning at 1000 DEG C in atmosphere for 6 h; and (3) adding a binder into the powder prepared in the step (2) and granulating, then performing compression molding, and finally sintering at 1050-1100 DEG C in atmosphere for 4 h, wherein the binder employs a polyvinyl alcohol solution with the mass concentration of 5% and the addition amount of polyvinyl alcohol is 3% by mass of the total powder. The prepared ceramic has good sintering, has the dielectric constant up to 8.1-8.8, has the quality factor Qf up to 131000-162000 GHz, has a small resonant-frequency temperature coefficient, and has extremely great application value in 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...

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Problems solved by technology

[0008] 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 with individual performance requirements, mainly because their resonant frequency temperature coefficient is usually too large or the quality factor Qf value 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, explore and develop near-zero resonant frequency temperature coefficient (-10ppm / ℃≤τ ? ≤+10ppm / ℃) and a series of different dielectric constant microwave dielectric ceramics with higher quality factors are difficult problems that those skilled in the art have been eager to solve but have always been difficult to achieve, which largely limits the use of microwave dielectric ceramics and device development

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