Low-temperature-sintering microwave dielectric ceramic Li2MgNb2O7 and preparation method thereof

Abstract

The invention discloses a low-temperature-sintering microwave dielectric ceramic Li2MgNb2O7 and a preparation method thereof. The preparation method comprises the following steps: (1) weighing and proportioning Li2CO3, MgO and Nb2O5 original powders with the purity of higher than 99.9% according to the composition of the Li2MgNb2O7; (2) carrying out wet ball milling mixing on the raw materials in the step (1) for 12 hours by using distilled water as a ball milling medium, drying, and presintering in an 850 DEG C atmospheric atmosphere for 6 hours; and (3) adding an adhesive into the powder prepared in the step (2), granulating, compacting, and finally, sintering in a 900-930 DEG C atmospheric atmosphere for 4 hours, wherein the adhesive adopts a 5 wt% polyvinyl alcohol solution, and the addition amount of the polyvinyl alcohol is 3% of the total mass of the powder. The ceramic has favorable sintering property at 900-930 DEG C, the dielectric constant reaches 25.6-26.3, the quality factor Qf value is up to 79000-88000 GHz, the temperature coefficient of resonance frequency is small, and the ceramic has great application value in industry.

Description

technical field [0001] The invention relates to a dielectric ceramic material, in particular to a microwave component such as a dielectric substrate used at a microwave frequency, a dielectric ceramic material of a ceramic capacitor or a temperature compensation capacitor 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 miniaturizat...

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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. A large number of exploratory studies have focused on Li-based binary or ternary compounds, and developed such as Li 2 TiO 3 , Li 2 MoO 4 and Li 2 MTi 3 o 8 (M=Mg or Zn) series of microwave dielectric ceramics with good performance, etc., but the microwave dielectric ceramic system that can be fired at low temperature is still relatively limited, and the τ of single-phase microwave dielectric ceramics with low inherent sintering temperature ? Usually large, can not meet the requirements of device thermal stability, which largely limits the development of low temperature co-firing technology and microwave multilayer devices

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