Bismuth-containing borate microwave dielectric ceramic with ultra-low dielectric constant

Abstract

The invention discloses bismuth-containing borate microwave dielectric ceramic BiW2B3O12 with an ultra-low dielectric constant and a preparation method thereof. The method comprises the following steps: (1) weighing initial powder of Bi2O3, WO3 and B2O3 having the purity of over 99.9 percent by weight according to the composition of BiW2B3O12; (2) mixing the raw materials in the step (1) by a wet ball mill for 12 hours by taking distilled water as a ball mill medium, drying, and preburning for 6 hours at an atmosphere of 750 DEG C; (3) adding an adhesive into the powder prepared in the step (2), granulating, pressing and molding, and sintering for 4 hours at atmosphere of 800-850 DEG C, wherein the adhesive is a polyvinyl alcohol solution having a mass concentration of 5 percent, and is 3 percent of total mass of the powder. The prepared ceramic has excellent sintering performance at 850 DEG C, has a dielectric constant of 8.1-8.7, a quality factor Qf of 71000-94000GHz and small resonant frequency temperature coefficient, and has a 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...

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 f ) 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 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

Exploration and development can not only sinter at low temperature but also have near-zero resonance frequency temperature coefficient (-10ppm / ℃≤τ f ≤+10ppm / °C) 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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