Low-loss stable-temperature molybdate microwave dielectric ceramic

Abstract

The invention discloses low-loss stable-temperature molybdate microwave dielectric ceramic Li3Eu3Mo2O12 and a preparation method thereof. The preparation method includes: (1) weighing original powder, higher than 99.9% (weight percentage) in purity, of Li2CO3, Eu2O3 and MoO3 according to a composition of Li3Eu3Mo2O12; (2) subjecting the raw materials prepared at the step (1) to wet ball milling for 12h, and pre-sintering in an air atmosphere for 6h at 1100 DEG C after drying, wherein distilled water serves as a ball milling medium; (3) adding a binding agent into powder prepared at the step (2), granulating, performing compression moulding, and sintering in the air atmosphere for 4h at 1150-1200 DEG C, wherein the binding agent is polyvinyl alcohol solution being 5% in mass concentration, and addition quantity of polyvinyl alcohol accounts for 3% of the total mass of the powder. The prepared ceramic is well sintered below 1200 DEG C, a dielectric constant reaches 11.3-11.9, a qualify factor Qf value is up to 79000-98000GHz, the temperature coefficient of resonance frequency is low, and an extremely high industrial application value is achieved.

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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