High-dielectric-constant lithium-niobium-titanium-based low-temperature-fired ceramics and preparation method thereof

Abstract

The invention discloses a high-dielectric-constant lithium-niobium-titanium-based low-temperature-fired microwave dielectric ceramic material and a preparation method thereof. The material disclosed by the invention can be prepared through the solid-phase reaction of a lithium-rich lithium-niobium-titanium-based material and a lithium borosilicate glass burning improver of an amount accounting for 1-10% by weight of a main crystal phase. The composition of the lithium-rich lithium-niobium-titanium-based material is Li1.0+xNb0.6Ti0.5O3-yLBS, wherein the LBS is the lithium borosilicate glass burning improver, x is not smaller than 0 but not greater than 0.2 (mole ratio), and y is not smaller than 0 but not greater than 0.1 (weight ratio). The LBS is prepared from the following raw materials: lithium carbonate (Li2CO3), silicon dioxide (SiO2) and boron oxide (B2O3). The low-temperature-fired microwave dielectric ceramics LTCC (Low-Temperature Co-fired Ceramics) prepared by the method have the advantages that the firing at the temperature of 850-900 DEG C is good, the high dielectric constant [epsilon]r is 65-70, the quality factor Qf is moderate, and the temperature coefficient of resonance frequency is small; the ceramics can be applied to the production of microwave devices, such as LTCC systems, multilayer dielectric resonators, microwave antennae, wave filters and the like, and have great application values in industry.

Description

technical field [0001] The invention belongs to the field of dielectric ceramics, in particular to low-temperature sintered microwave dielectric ceramic materials. 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. Chips, dielectric waveguide circuits and other components are the key basic materials of modern communication technology. They have very important applications in portable mobile phones, TV satellite receivers, and military radars. In the process of miniaturization and integration of modern communication tools Zhongzheng is playing an increasingly important role. [0003] Dielectric ceramics used in the microwave frequency band should meet the requirements: (1) High dielectric constant to facilitate ...

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Problems solved by technology

However, the sintering temperature of undoped lithium-niobium-titanium ceramics is relatively high (1100°C), and cannot be directly co-fired with low melting point metals such as Ag and Cu.

[0004] In order to reduce the sintering temperature, low melting point fluxes are used in the study of lithium niobium titanium ceramic materials, such as salts or oxides containing boron and vanadium. Stable, which limits its practical application; while using other salts or oxides that do not contain boron and vanadium as flux or additives, the performance or process of the material is difficult to meet the requirements, which greatly limits lithium niobium titanium materials and microwave multilayer devices. development of

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