Temperature stable ultra-low dielectric constant microwave dielectric ceramics that can be sintered at low temperature

Abstract

The invention discloses temperature stable type microwave dielectric ceramic with an ultra low dielectric constant capable of being sintered at a low temperature and a preparation method of the temperature stable type microwave dielectric ceramic. The preparation method comprises the specific steps: weighing and dosing original powder, with purity of 99.9% (in percentage by weight) of La2O3, Li2CO3, ZnO and SiO2 according to the composition of La3LiZnSi3O12; then, performing wet type ball-milling and mixing on the raw materials for 12 hours, and pre-sintering for 6 hours at 850 DEG C in an atmosphere, wherein a ball-milling medium is absolute ethyl alcohol; after adding a binder into the prepared powder and pelletizing, pressing and molding; and finally sintering for 4 hours at 900-940 DEG C in the atmosphere; the binder adopts a polyvinyl alcohol solution with mass concentration of 5%, and the adding amount of the polyvinyl alcohol accounts for 3% of the total mass of the powder. The ceramic prepared by the preparation method disclosed by the invention has good sintering performance at 900-940 DEG C, has a dielectric constant of 6.3-6.7, a quality factor Qf value as high as 87000-125000GHz, a small resonant frequency temperature coefficient, and an 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...

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

Images