Low-dielectric-constant microwave dielectric ceramic Ag3LiTi2O6 with near-zero resonance frequency temperature coefficient

Abstract

The invention discloses a low-dielectric-constant microwave dielectric ceramic Ag3LiTi2O6 which can be subjected to low temperature sintering and has a near-zero resonance frequency temperature coefficient and a preparation method thereof. The preparation method comprises the following steps: weighing and batching original powder of AgNO3, Li2CO3 and TiO2 of which the purity is more than 99.9% (in percentage by weight) according to the composition of Ag3LiTi2O6; (2) performing wet ball milling and mixing on raw materials in the step (1) for 12 hours by using distilled water as a ball milling medium, drying, and then pre-sintering for 6 hours in an atmosphere at 800 DEG C; and (3) adding a binding agent into powder prepared in the step (2) and pelletizing, then performing compression molding, and finally sintering for 4 hours in the atmosphere at 850-880 DEG C, wherein the binding agent adopts a polyvinyl alcohol solution with the mass concentration of 5%, and the addition amount of polyvinyl alcohol accounts for 3% of the total mass of the powder. The ceramic prepared by using the method disclosed by the invention is good in sintering performance at 850-880 DEG C, ensures that the dielectric constant reaches 28.7-29.4, the quality factor (Qf) value reaches 53000-57000GHz, and the temperature coefficient of resonance frequency is close to zero, and has extremely large application values in industry.

Description

technical field [0001] The invention relates to a dielectric ceramic material, in particular to a dielectric ceramic material used for manufacturing microwave components such as ceramic dielectric substrates, resonators and filters, 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. [0003] Dielectri...

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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 be practically produced and applied.

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 low-permittivity microwave dielectric ceramics that can be sintered at low temperature and have near-zero resonant frequency temperature coefficient and high quality factor is a difficult problem that those skilled in the art have been eager to solve but have always been difficult to achieve.

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