High specific saturation magnetization and high coercitive force strontium ferrite magnetic powder and preparation thereof

A strontium ferrite magnetic powder, magnetization technology, applied in the preparation of strontium ferrite magnetic powder, strontium ferrite magnetic powder field, can solve the problem of low magnetic properties of ferrite powder, achieve high coercive force, high Effect of Specific Saturation Magnetization

Inactive Publication Date: 2009-02-25
QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] The purpose of the present invention is to provide a method for preparing strontium ferrite magnetic powder with high specific saturation magnetization and high coercive force for the defect that the ferrite powder prepared by the prior art has low magnetic properties

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Weigh iron nitrate (Fe(NO 3 ) 3 ·6H 2 O) 60.6243g, strontium nitrate (Sr(NO 3 ) 2 ) 2.55354g, lanthanum nitrate (La(NO 3 ) 3 ·6H 2 O) 1.0991g, and cobalt chloride (CoCl 3 ·6H 2 O) 0.6257g.

[0038] Put the above-mentioned weighed raw materials in a beaker, add 500ml of deionized water, stir and dissolve fully to obtain a mixed solution A; then add 149g of citric acid to the mixed solution A, stir and dissolve to obtain a solution B; Adjust the pH value to 7.5 with ammonia gas to obtain dark green sol C; sol C evaporates the solvent at 80°C for 6 hours to form gel D; move the gel D to a muffle furnace at 500°C, the gel rapidly expands and smokes, and burn to obtain fluffy and porous black powder precursor E; grind the precursor powder E in a mortar, put it into a corundum crucible, and calcinate and keep it at a constant temperature of 700°C for 4 hours to obtain strontium ferrite fine powder.

[0039] The composition of the obtained strontium ferrite micropowd...

Embodiment 2

[0041] Weigh iron nitrate (Fe(NO 3 ) 3 ·6H 2 O) 60.6243g, strontium nitrate (Sr(NO 3 ) 2 ) 2.55354g, lanthanum nitrate (La(NO 3 ) 3 ·6H 2 O) 1.0991g, and cobalt chloride (CoCl 3 ·6H 2 O) 0.6257g.

[0042] Put the above-mentioned weighed raw materials in a beaker, add 500ml of secondary water, stir and fully dissolve to obtain a mixed solution A; then add 149g of citric acid to the mixed solution A, stir and dissolve to obtain a solution B; Adjust the pH value to 7.5 with ammonia gas to obtain dark green sol C; sol C evaporates the solvent at 80°C for 6 hours to form gel D; move gel D to a muffle furnace at 500°C, the gel rapidly expands and smokes , and burned to obtain a fluffy and porous black powder precursor E; weigh 30g of the precursor powder E, nano-SiO with a particle size of 20-80nm 2 0.15g, nano-CaCO with particle size less than 100nm 3 0.20g, 0.35g of calcium gluconate, put in a beaker, add 45ml of water, stir and mix for 30 minutes to obtain a viscous ...

Embodiment 3

[0045] Weigh iron nitrate (Fe(NO 3 ) 3 ·6H 2 O) 60.6243g, strontium nitrate (Sr(NO 3 ) 2 ) 2.55354g, lanthanum nitrate (La(NO 3 ) 3 ·6H 2 O) 0.5496g, ammonium cerium nitrate ((NH 4 ) 2 Ce(NO 3 ) 4 ) 0.3477g, yttrium nitrate (Y(NO 3 ) 3 ·6H 2 O) 0.2510g and cobalt chloride (CoCl 3 ·6H 2 O) 0.6257g.

[0046] Put the above-mentioned weighed raw materials in a beaker, add 500ml of deionized water, stir and dissolve fully to obtain a mixed solution A; then add 149g of citric acid to the mixed solution A, stir and dissolve to obtain a solution B; Adjust the pH value to 7.5 with ammonia gas to obtain dark green sol C; sol C evaporates the solvent at 80°C for 6 hours to form gel D; move the gel D to a muffle furnace at 500°C, the gel rapidly expands and smokes, And burn it to get the fluffy and porous black powder precursor E; grind the precursor powder E in a mortar, put it into a corundum crucible, and calcinate it at 700°C for 4 hours to get the strontium ferrite fi...

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Abstract

The invention provides a method for preparing a strontium ferrite magnetic powder with high specific saturation magnetization and high coercive force. Nitrates and chlorides of Sr, R Fe and M with limited amounts are dissolved, added with citric acid and ammonia gas to adjust the solution obtained to neutral or slightly alkaline so as to prepare sol; the sol is heated and evaporated to prepare gel, a precursor is prepared by self-propagating combustion, and the magnetic powder is obtained by calcining the precursor at a low temperature. In the composition, R is at least one of Y, La, Pr, Nd and Ce, and M is at least one of Co, Ni, Zn, Cu and Mn. In the method, the magnetic powder can be obtained by mixing, ball milling, calcining, fine grinding and annealing the precursor obtained by self-propagating combustion and at least one of the nano-grade SiO2, CaCO3, B2O3, SrSO4, Al2O3 and Cr2O3. The magnetic powder prepared by the technology has the specific saturation magnetization of 71-75emu/g and the coercive force of 5.5-6.5kOe. The magnetic powder is suitable for preparing bonded permanent magnets and automobile motor magnets requiring high magnetic property.

Description

technical field [0001] The invention belongs to the technical field of preparation of nanometer functional materials, and relates to a method for preparing strontium ferrite magnetic powder, in particular to a method for preparing strontium iron with high specific saturation magnetization, high coercive force and high remanence by using sol-gel technology Oxygen magnetic powder method. technical background [0002] The sol-gel method is one of the main methods for preparing nanopowders. This technology forms metal complexes through complexing agents and metal ions, and then forms polymer gels through crosslinking. In the gel, the metal ions are evenly distributed, and during the process of removing the gelling agent by heat treatment, the metal ions undergo oxidation reactions to form nano-oxide materials. There are two ways to remove the gelling agent: thermal decomposition and combustion. The temperature and holding time of heat treatment play a decisive role in the part...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/26C04B35/622
Inventor 祁米香龙光明刘美英王舒娅
Owner QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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