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Process for synthesizing barium ferrite micro powder by self combustion method

A technology of barium ferrite and self-combustion method, which is applied in the field of preparing barium ferrite micropowder, can solve the problems of difficulty in precipitation and washing, complicated equipment, and difficulty in industrialized production, and achieves the effect of high purity

Inactive Publication Date: 2005-08-17
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Co-precipitation method has simple process, convenient operation, low cost, uniform barium ferrite particles, easy adjustment, and easy industrial production. The disadvantage is that it is difficult to wash the precipitate; the equipment and instruments of hydrothermal method are expensive, and high-pressure operation is not easy for industrial production; The glass crystallization process can obtain barium ferrite single crystal with fine particle size and narrow distribution, and has good magnetic properties, but the equipment is complicated and the cost is high; the sol-gel technology has the molecular level mixing of raw materials, and the product composition and ion substitution are easy Control, narrow particle size distribution, excellent magnetic properties, etc., but the synthesis of powder requires a higher temperature, and the powder may agglomerate

Method used

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  • Process for synthesizing barium ferrite micro powder by self combustion method
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  • Process for synthesizing barium ferrite micro powder by self combustion method

Examples

Experimental program
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Effect test

Embodiment 1

[0021] The method for synthesizing barium ferrite micropowder by self-combustion method, the concrete steps are: first in a reactor, adding 80ml concentration is 0.75M Fe(NO 3 ) 3 Solution, M is the molar concentration, and in another reactor, adding 20ml concentration is 0.25M Ba(NO 3 ) 2 solution. Under stirring conditions, the above two solutions were mixed to obtain a mixed solution A. Then add 0.19mol citric acid into the mixed solution A, and stir to obtain the mixed solution B. Adjust the pH value of the mixed solution B to 7.5 with ammonia water, heat while stirring at 75°C, and the following chemical reaction occurs:

[0022]

[0023]

[0024]

[0025] As the solvent evaporates, the viscosity of the solution increases, and the resulting complexes are linked by hydrogen bonds, forming a gel in 8-12 hours. After the gel is formed, move it to a constant temperature electric furnace at 200°C. The dry gel begins to expand, boil, and smoke in about...

Embodiment 2

[0032] The method for synthesizing barium ferrite micropowder by self-combustion method, the concrete steps are: first in a reactor, adding 80ml concentration is 0.75M Fe(NO 3 ) 3 solution, add 20ml concentration of 0.25M Ba(NO 3 ) 2 solution. Under stirring conditions, the above two solutions were mixed to obtain a mixed solution A. Then add 0.19mol citric acid into the mixed solution A, and stir to obtain the mixed solution B. Use ammonia water to adjust the pH value of the mixed solution B to 8.0, heat it while stirring at 80°C, and the following chemical reaction occurs:

[0033]

[0034]

[0035]

[0036] As the solvent evaporates, the viscosity of the solution increases, and the resulting complexes are linked by hydrogen bonds, forming a gel in 8-12 hours. After the gel is formed, move it to a constant temperature electric furnace at 200°C. The dry gel begins to expand, boil, and smoke in about 1 minute, and then generates a flame and discharges...

Embodiment 3

[0043] The method for synthesizing barium ferrite micropowder by self-combustion method, concrete steps are: first add 80ml concentration in a reactor and be 1.0M Fe(NO 3 ) 3 solution, add 20ml concentration of 0.125M Ba(NO 3 ) 2 solution. Under stirring conditions, the above two solutions were mixed to obtain a mixed solution A. Then add 0.57mol citric acid into the mixed solution A, and stir to obtain the mixed solution B. Use ammonia water to adjust the pH value of the mixed solution B to 8.5, heat while stirring at 85°C, and the following chemical reactions occur:

[0044]

[0045]

[0046]

[0047] As the solvent evaporates, the viscosity of the solution increases, and the resulting complexes are linked by hydrogen bonds, forming a gel in 8-12 hours. After the gel is formed, move it to a constant temperature electric furnace at 200°C. The dry gel begins to expand, boil, and smoke in about 2 minutes, and then generates a flame and emits a large am...

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Abstract

The self-combustion process of synthesizing fine barium ferrite powder includes the following steps: 1) compounding 0.125-0.25 M barium nitrate solution, compounding 0.125-1.0 M ferric nitrate solution, and mixing via stirring to obtain mixed solution an of molar Fe / Ba ratio in 12; 2) mixing citric acid with mixed solution A to obtain mixed solution B with the molar ratio between nitrate radical and citric acid of 1 to 1-3 through stirring, regulating pH value with acid or alkali to 7.5-8.5, heating at 75-85 deg.c to evaporate for 8-12 hr to form gel; 3) evaporating water of the gel and self-spreading combustion in electric furnace at 200 deg.c to form powder precursor; and 4) calcining the powder precursor at 600-700 deg.c for 2-4 hr to obtain the fine barium ferrite powder. The present invention has the features of low synthesis temperature, high product purity and small average grain size.

Description

technical field [0001] The invention relates to a method for preparing barium ferrite micropowder. Background technique [0002] Barium ferrite (BaFe 12 o 19 ) As a magnetic material of the hexagonal crystal system, it can be used as permanent magnet material, microwave absorbing material, perpendicular magnetic recording material and magneto-optical recording material, etc. It has been widely used in high frequency equipment. There are many methods to prepare barium ferrite, such as chemical co-precipitation method, hydrothermal method, glass crystallization method and sol-gel method. Co-precipitation method has simple process, convenient operation, low cost, uniform barium ferrite particles, easy adjustment, and easy industrial production. The disadvantage is that it is difficult to wash the precipitate; the equipment and instruments of hydrothermal method are expensive, and high-pressure operation is not easy for industrial production; The glass crystallization proces...

Claims

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Application Information

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IPC IPC(8): B22F9/30
Inventor 戴红莲李世普黄健韩颖超王欣宇黄福龙邵海成贺建华齐志涛
Owner WUHAN UNIV OF TECH
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