Process for preparing tetragonal nanoparticles of barium titanate

A technology of phase barium titanate and nano powder, which is applied in the field of preparing tetragonal phase barium titanate nano powder, can solve the problems of low purity, growth, expensive raw materials, etc., and achieve simple preparation process, process parameter control, process parameter easy effect

Inactive Publication Date: 2003-01-15
TSINGHUA UNIV
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Problems solved by technology

The traditional solid-phase sintering method has been eliminated due to its low product purity, large particle size, and poor component uniformity, which cannot meet the needs of electronic ceramics production; the commonly used preparation method is to subject the first synthesized barium titanyl oxalate powder to ℃ thermal decomposition to obtain tetragonal phase barium titanate powder
Due to the high-temperature heat treatment, the particle size of the powder will inevitably grow up. The average particle size of the barium titanate powder obtained by this method is submicron or micron, and nano-scale powder cannot be obtained; low-temperature wet chemical synthesis method, such as water Thermal method, sol-gel method and citric acid method, etc., although nano-scale barium titanate can be obtained, most of them are cubic phases, and even contain a small amount of barium carbonate heterophase, which requires further high-temperature heat treatment to obtain tetragonal phases, and due to The raw materials are expensive and the requirements for the reaction device are high, resulting in high cost, which is not conducive to mass production

Method used

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  • Process for preparing tetragonal nanoparticles of barium titanate
  • Process for preparing tetragonal nanoparticles of barium titanate
  • Process for preparing tetragonal nanoparticles of barium titanate

Examples

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Embodiment 1

[0022] Example 1: Add 10ml of titanium tetrachloride dropwise to 50ml of ice water to form an aqueous solution of titanium tetrachloride, then add 1 liter of 1.5 mol / liter of ammonia water to form white hydrated TiO 2 The precipitate was dissolved in 12.2ml of concentrated nitric acid in an ice bath environment. If it cannot be dissolved temporarily, it can be placed in the freezer at low temperature to achieve dissolution. This gives a transparent titanyl nitrate solution. Barium nitrate, titanyl nitrate, citric acid and ammonium nitrate are mixed in a molar ratio of 1:1:3:17, and the mixed aqueous solution is adjusted to a pH value of 6-7 with ammonia water, and then heated and evaporated at 95°C until the water is evaporated to dryness. It is a brown viscous substance accompanied by bubbles. The ignition temperature is about 300°C when it is ignited and burns rapidly. The reaction is completed within a few minutes and a fluffy white titanium-barium powder is formed. It is ...

Embodiment 2

[0023] Embodiment 2: barium nitrate, titanyl nitrate, citric acid and ammonium nitrate are mixed with 1: 1: 2: 8 molar ratio, other is the same as embodiment 1. Such as figure 2 X-ray diffraction pattern (S 1 ), the X-ray diffraction analysis results show that the powder is tetragonal phase barium titanate, and does not contain the diffraction peaks of cubic phase barium titanate and barium carbonate. The grain size is about 50-80nm.

Embodiment 3

[0024] Embodiment 3: barium nitrate, titanyl nitrate, citric acid and ammonium nitrate are mixed with 1: 1: 4: 26 molar ratio, other is the same as embodiment 1. Such as figure 2 X-ray diffraction pattern (S 3 ), the X-ray diffraction analysis results show that the powder is tetragonal phase barium titanate, and does not contain the diffraction peaks of cubic phase barium titanate and barium carbonate. The grain size is about 100-150nm.

[0025] figure 2 For the X-ray diffraction pattern of the barium titanate nanocrystal prepared by the method provided by the invention, the diffraction pairs such as (001), (100), (200), (102), (112), (211) appearing in the figure The peak is the characteristic diffraction peak of tetragonal barium titanate.

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Abstract

A process for preparing the tetragonal nanoparticles of barium titanate includes such steps as preparing solution of titanium nitrate oxide, proportionally mixing it with the aqueous solution of barium nitrate, citric acid and ammonium nitrate, heating for becoming colloid by evaporation, and burning. Its advantage are high purity, easily controlled granularity, and low cost.

Description

technical field [0001] The invention belongs to the field of preparation of electronic raw materials, and in particular relates to a method for preparing tetragonal barium titanate nanopowder, which is used to prepare products by a low-temperature combustion method. technical background [0002] As an important electronic ceramic material with perovskite structure, barium titanate has three crystal forms: cubic phase, tetragonal phase and hexagonal phase. Among them, the tetragonal phase has become the most widely used crystal form because of its piezoelectricity, ferroelectricity and pyroelectricity. The traditional solid-phase sintering method has been eliminated due to its low product purity, large particle size, and poor component uniformity, which cannot meet the needs of electronic ceramics production; the commonly used preparation method is to subject the first synthesized barium titanyl oxalate powder to ℃ thermal decomposition to obtain tetragonal phase barium tita...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G23/00C04B35/468
Inventor 张中太罗绍华唐子龙尧巍华
Owner TSINGHUA UNIV
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