Tantalate dielectric ceramic with stable temperature and preparation method thereof

Abstract

The invention discloses a tantalate dielectric ceramic with stable temperature and a preparation method thereof. The general formula of the ceramic chemical composition comprises Ba[6-x]Ln[x]Fe[1+0.5x]Ta[9-0.5x]O30, wherein Ln is one or two compositions out of La, Pr, Nd and Sm; and x is not less than 0.00 and not more than 2. The preparation method comprises the following steps of preparing and mixing the original powders of BaCO3, Ln2O3, Fe2O3 and Ta2O5 with the purity of more than 99% according to the stoichiometric proportion of the chemical formula; ball-milling the mixture for 12-24h in a wet-type way with a solvent of distilled water, drying and pre-baking the mixture in the atmosphere at the temperature of 1350-1400 DEG C for 4-8h, subsequently adding adhesive in the pre-baked powder and granulating, pressing and forming the mixture, finally baking the mixture in the atmosphere at the temperature of 1400-1450 DEG C for 1-8h, wherein the adhesive adopts a polyvinyl alcohol solution with the mass concentration of 5% and the amount of the adhesive is 2%-10% of the total amount of the pre-baked powder. The method has simple preparation process, and the ceramic prepared by the method has high dielectric constant, low dielectric loss and small dielectric constant temperature coefficient Tau[Epsilon].

Description

Technical field [0001] The invention relates to a dielectric ceramic material, in particular to a temperature stable ceramic material used in ceramic capacitors and a preparation method thereof. Background technique [0002] Temperature stability is very important for the preparation of multilayer ceramic capacitors used in electronic products. Pass two or more temperature coefficients with opposite dielectric constants (τ ε ) Is mixed to produce a solid solution with a smaller temperature coefficient of dielectric constant. This method is often used to achieve the temperature stability of the material; or, for example, for BaTiO 3 Based capacitors, dopants are mixed and dispersed in the ceramic body to produce a ferroelectric-paraelectric phase transition near room temperature, and a relatively stable material is obtained. Currently, BaTiO 3 The base compound satisfies the X7R standard, and the change rate of the dielectric constant relative to room temperature within the temper...

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Problems solved by technology

At present, the temperature coefficient of dielectric constant of these tungsten bronze structure tantalates is relatively large, and the temperature stability is not good, so its practical application is limited.