Low-temperature sinterable ultra-low dielectric constant microwave dielectric ceramic li3biw8o27

Abstract

The invention discloses ultralow dielectric constant microwave dielectric ceramic Li3BiW8O27 capable of performing low-temperature sintering and a preparation method of the ultralow dielectric constant microwave dielectric ceramic Li3BiW8O27. The preparation method comprises the following steps: (1) weighing and dosing the original powder, having the purity more than 99.9wt%, of Li2CO3, Bi2O3 and WO3 according to the composition of Li3BiW8O27; (2) performing wet ball-milling on the raw material in the step (1), mixing for 12 hours, wherein the ball-milling medium is distilled water, and pre-sintering in the atmosphere at the temperature of 650 DEG C after drying; and (3) adding an adhesive into the powder prepared in the step (2), granulating, performing compression molding, and finally sintering in the atmosphere at the temperature of 700-730 DEG C, wherein the adhesive refers to 5% polyvinyl alcohol solution, and the addition amount of polyvinyl alcohol accounts for 3 percent of the total mass of the powder. The ceramic prepared by the invention has high sintering property at the temperature of 700-730 DEG C and has extremely high application values in the industry, the dielectric constant of the ceramic is 7.6-8.3, the quality factor Qf value reaches 54000-71000GHz, and the resonant frequency temperature coefficient is low.

Description

technical field [0001] The invention relates to a dielectric ceramic material, in particular to a dielectric ceramic material used to manufacture microwave components such as dielectric substrates, ceramic 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] Dielectric c...

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Problems solved by technology

[0010] 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 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 individual performance and can be sintered at low temperature, and 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 (│±τ ? │≤10ppm / ℃) and microwave dielectric ceramics with higher 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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