Process for synthesizing nano barium ferrite powder by microwave induction and low-temp combustion

A low-temperature combustion synthesis, barium ferrite technology, applied in the direction of inorganic material magnetism, can solve the problem of unretrieved powder, etc., achieve the effect of low equipment requirements, narrow particle size distribution, and improved magnetic properties

Inactive Publication Date: 2002-11-13
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Microwave combustion synthesis has opened up a new field of combustion synthesis, and the basic and applied research in material synthesis is still in progress. At present, no relevant microwave-induced low-temperature combustion synthesis of hexagonal nano-BaFe has been retrieved. 12 o 19 powder report

Method used

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  • Process for synthesizing nano barium ferrite powder by microwave induction and low-temp combustion
  • Process for synthesizing nano barium ferrite powder by microwave induction and low-temp combustion
  • Process for synthesizing nano barium ferrite powder by microwave induction and low-temp combustion

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Use barium nitrate, ferric nitrate, citric acid and chloride as raw materials, according to Ba 2+ : Fe 3+ : citric acid: chloride molar ratio=1: 11.5: 30: 1 (chloride is the mixture of NaCl / KCl molar ratio=1: 1) batching, and method is as follows: respectively with nitrate, citric acid, be dissolved in deionized water , to make a solution, stir continuously after mixing, adjust the pH to 7 with ammonia water, then add chloride solution, stir well, and place it in a microwave cavity for heating. The microwave frequency is 2450MHz, and the input power is 500W. The solution first boils and bubbles, and as the water evaporates, a gel is formed. When reaching a certain temperature, the gel starts to ignite and burn, and a loose, foamy powder is obtained. The above powder was heat-treated at 700°C in air for 4 hours, washed with water to remove chlorides, and the final product was obtained. Its magnetic properties are: specific saturation magnetization σ s =55.79emu / g, i...

Embodiment 2

[0030]Use barium nitrate, ferric nitrate, citric acid, sodium chloride as raw materials, according to Ba 2+ : Fe 3+ : citric acid: sodium chloride = 1: 11.5: 26: 3 (molar ratio) ingredients, the method is as follows: respectively dissolve nitrate, citric acid, and deionized water to make a solution, stir continuously after mixing, and adjust with ammonia water PH is equal to 5, then add sodium chloride solution, stir well, and heat in a microwave cavity. The microwave frequency is 2450MHz, and the input power is 500W. The solution first boils and bubbles, and as the water evaporates, a gel is formed. When reaching a certain temperature, the gel starts to ignite and burn, and a loose, foamy powder is obtained. The above-mentioned powder is rapidly heated to 800°C, kept for 50 minutes, washed with water to remove chlorides, and the final product is obtained. The magnetic properties are: specific saturation magnetization σ s =66.79emu / g, intrinsic coercive force jHc=5.08KOe....

Embodiment 3

[0032] Using barium carbonate, ferric nitrate, citric acid, sodium chloride as raw materials, according to Ba 2+ : Fe 3+ : citric acid: sodium chloride = 1: 12: 15: 2 (molar ratio) batching, the method is as follows: respectively dissolve nitrate, citric acid, and deionized water to make a solution, stir constantly after mixing, adjust with ammonia water When the pH is equal to 6, add sodium chloride solution, stir well, and heat in a microwave cavity. The microwave frequency is 2450MHz, and the input power is 500W. The solution first boils and bubbles, and as the water evaporates, a gel is formed. When reaching a certain temperature, the gel starts to ignite and burn, and a loose, foamy powder is obtained. The above-mentioned powder was heat-treated at 800°C for 2 hours in the air and then washed with water to remove chlorides to obtain the final product. The magnetic properties are: specific saturation magnetization σ s =64.79emu / g, intrinsic coercivity jHc=4.587KOe. I...

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Abstract

A process for synthesizing nanometre BaFe12O19 powder includes such steps as proportionally mixing the inorganic salt (nitrate or carbonate) of Ba2+ or Fe3+, citric acid and chloride (potassium chloride, sodium chloride, or their combination in mol ratio of NaCl/KCl=1:0.5-1.5), microwave inducing, low-temp. combustion for 2-10 min, heat treating under 900 deg.c for 0.2-10 hr and water washing to obtain nanometre hexagonal crystal of BaFe12O19. Its advantages are simple process, low energy consumption, and regulatable magnetic performance of product.

Description

technical field [0001] The invention relates to a hexagonal (M-type) nano-barium ferrite (BaFe 12 o 19 ) powder synthesis method, especially a microwave-induced low-temperature combustion synthesis of nano-hexagonal BaFe 12 o 19 The powder method belongs to the field of magnetic material preparation. Background technique [0002] M-type barium ferrite can be used as permanent magnet material, magnetic recording material and ultra-high frequency gyromagnetic material due to its high coercive force and uniaxial anisotropy. In order to finally realize the tailoring of material properties, the controllability of powder composition and particle size is the key problem to be solved. At present, the main preparation methods of nano M-type barium ferrite powder include chemical co-precipitation method, molten salt method, metal organic compound hydrolysis method, sol-gel method, glass crystallization method, hydrothermal method, liquid mixing method, etc. . Although the above ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/26C04B35/64H01F1/10
Inventor 黄建国庄汉锐李文兰
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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