Method of synthesizing nano grade calcium titanium ceramic powder

Abstract

A process for synthesizing the nanometre-class perovskite ceramic powder under the conditions of temp. lower than boiling point of substrate liquid and normal pressure includes such steps as directlymixing the substrate liquid which is the aqueous solution of barium hydroxide, strontium hydroxide, calcium hydroxide and lead hydroxide with the solution of metallic alkoxide in organic solvent, adding precipitant and disperser, and drying the deposit. Its advantages are high sintering activity, uniformity and stability of Ba / Ti rate, and cubic perovskite structure.

Description

technical field [0001] The invention relates to the preparation technology of ultrafine nanometer powder, in particular to a synthesis method of nanoscale perovskite ceramic powder. Background technique [0002] A class of ceramic materials with a perovskite structure represented by barium titanate is widely used in various electronic components due to its excellent ferroelectric and piezoelectric properties, such as multilayer ceramic capacitors (MLCC), positive Temperature coefficient thermistor (PTCR), piezoelectric motor, ceramic filter, etc. The purity and fineness of perovskite ceramic powder have a decisive influence on the performance and quality of electronic ceramic components. With the rapid development of electronic components in the direction of high integration, high precision, high reliability, multi-function and miniaturization, the electronics industry is concerned about the purity, particle size, and molding of barium titanate and other powders with perovs...

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Problems solved by technology

[0005] Chinese patent CN1101634A proposes to co-precipitate an aqueous solution of two or more metal ions (Ba, Ti, Sr, Zr, etc.) in an alkaline environment (aqueous solution) with pH = 14 (not lower than 13.6), and the temperature range is 70~ The particle size of the powder obtained after washing and drying the precipitate at 100°C is 70-400nm, but due to the use of strong alkali such as NaOH, KOH, etc. The purity of the body is difficult to guarantee, and in order to obtain a smaller particle size, it is necessary to add BETA-cyclodextrin as a dispersant, which increases the difficulty of the process and operation, and increases the cost of the product

S.Urek of Slovenia etc. have reported a kind of low-temperature hydrothermal method (J.Euro.Ceram.Soc., 18 (1997): 279-286), the aqueous solution of barium ion and the alcoholic solution of titanium ion are under strong alkaline environment Mixing to form a prepolymer, and then a perovskite micropowder precipitation (~20nm) was obtained at a lower temperature of 150°C, but the temperature of this method has exceeded the boiling point of water, and it must be in a high-pressure chamber to reach a supercritical state. In fact, it belongs to the hydrothermal synthesis method at a lower temperature, and it is difficult to get rid of the limitations of the hydrothermal synthesis method

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