Temperature-stable low-dielectric-constant microwave dielectric ceramic CaLi3Nd3W2O13

Abstract

The invention discloses a high-quality-factor temperature-stable low-dielectric-constant microwave dielectric ceramic CaLi3Nd3W2O13 and a preparation method thereof. The method comprises the following steps: (1) CaCO3, Li2CO3, Nd2O3 and WO3 original powders with purities higher than 99.9% (weight percentage) are weighed and blended according to the composition of CaLi3Nd3W2O13; (2) the raw material obtained in the step (1) is subjected to wet ball milling for 12h, wherein a ball milling medium is distilled water; after drying, the material is pre-sintered for 6h under a temperature of 720 DEG C in an air atmosphere; and (3) a binding agent is added to the powder obtained in the step (2), granulation and compression molding are carried out; and sintering is carried out for 4h under a temperature of 770-820 DEG C in an air atmosphere. The binding agent is a polyvinyl alcohol solution with a mass concentration of 5%, wherein the addition amount of polyvinyl alcohol accounts for 3% of the total mass of the powder. The ceramic provided by the invention can be well sintered under a temperature below 820 DEG C. The dielectric constant of the ceramic reaches 23.1-23.8, and the quality factor Qf of the ceramic reaches 123000-161000GHz. The ceramic has a low resonance frequency temperature coefficient, and has high application value in industrial application.

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-fire microwave dielectric ceramic materials, material systems such as Li-based compounds, Bi-based compounds, molybdate-based 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 meet the requirements of practical applications.

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

Images