Temperature stable ultra-low dielectric constant microwave dielectric ceramic BaBi2W6O22

Abstract

The invention discloses temperature stable ultra-low dielectric constant microwave dielectric ceramic BaBi2W6O22 which can be sintered at low temperature and a preparation method thereof. The method comprises the following steps: (1) weighing the following original powder with purity of over 99.9wt%: BaCO3, Bi2O3 and WO3 according to the composition of BaBi2W6O22; (2) mixing the raw materials in the step (1) by wet grinding for 12 hours by adopting distilled water as the grinding medium, baking, and pre-burning in the atmosphere at 700 DEG C for 6 hours; (3) adding a binder into the powder prepared in the step (2), granulating, pressing and forming, and sintering in the atmosphere at 750-780 DEG C for 4 hours, wherein the binder is prepared from polyvinyl alcohol solution with mass concentration of 5 percent, and the additive amount of polyvinyl alcohol is 3 percent of the total mass of the powder. The ceramic prepared by the method is well sintered at 750-780 DEG C, has the dielectric constant being 17.8-18.4 and the quality factor Qf value being up to 55000-67000GHz, has a small temperature coefficient of resonance frequency, and 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 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

Explore and develop low-temperature sintering and near-zero resonant frequency temperature coefficient (-10 ppm / ℃≤τ ? ≤+10 ppm / ℃) and high quality factor microwave dielectric ceramics are difficult problems that those skilled in the art have been eager to solve but have always been difficult to achieve

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