Method for improving coercive force of spinelle iron-cobalt ferrite CoFe2O4

A technology of cobalt ferrite and coercive force, which is applied in the field of ferrite material preparation, can solve problems such as coercive force not involved in ferrite, achieve lower raw material prices, fine and uniform powder, lower sintering temperature and energy consumption effect

Active Publication Date: 2014-12-17
安徽中马磁能科技股份有限公司
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

However, none of the existing patents deal with CoFe 2 o 4 Increased coercive force of ferrite

Method used

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  • Method for improving coercive force of spinelle iron-cobalt ferrite CoFe2O4
  • Method for improving coercive force of spinelle iron-cobalt ferrite CoFe2O4
  • Method for improving coercive force of spinelle iron-cobalt ferrite CoFe2O4

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Experimental program
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Embodiment 1

[0027] 1) Preparation of SrFe 12 o 19 Powder: to analyze pure nitrate (Sr(NO 3 ) 2 , Fe(NO 3 ) 3 ) as raw material to prepare 2mmol of SrFe 12 o 19 Powder, the molar ratio of Fe and Sr in the raw material is 4:1, and Sr(NO 3 ) 2 2mmol, Fe(NO 3 ) 3 8mmol; according to molar ratio Proportioning required NaOH, that is, 84mmolNaOH is required. The nitrate raw material was dissolved in 45 ml deionized water, and the NaOH was dissolved in 30 ml deionized water. Then, NaOH solution was added dropwise to the mixed nitrate solution while stirring to precipitate metal ions, and the precipitate and precipitate were transferred into a 100ml hydrothermal reaction kettle for hydrothermal reaction, and the reaction temperature condition was 220°C×5h. The powder obtained after the reaction was washed 3 times and 2 times with deionized water and absolute ethanol, respectively. In order to ensure the purity of the phase, the obtained SrFe 12 o 19 The ferrite powder was washed on...

Embodiment 2

[0032] CoFe 2 o 4 and SrFe 12 o 19 The preparation method of nanopowder is the same as embodiment 1, in CoFe 2 o 4 The powder is mixed with SrFe according to the mass ratio of 10% 12 o 19 Powder, mixed evenly, pressed into tablets, sintered at 900°C for 2 hours to obtain CoFe with increased coercive force 2 o 4 .

[0033] The resulting CoFe with enhanced coercivity 2 o 4 The room temperature hysteresis loop of the sample is shown in image 3 middle.

Embodiment 3

[0035] CoFe 2 o 4 and SrFe 12 o 19 The preparation method of nanopowder is the same as embodiment 1, in CoFe 2 o 4 The powder is mixed with SrFe according to the mass ratio of 6% 12 o 19 Powder, mixed evenly, pressed into tablets, sintered at 700°C for 2 hours to obtain CoFe with increased coercive force 2 o 4 .

[0036] The resulting CoFe with enhanced coercivity 2 o 4 The room temperature hysteresis loop of the sample is shown in Figure 4 middle.

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Abstract

The invention discloses a method capable of significantly improving the coercive force of spinelle CoFe2O4 ferrite and belongs to the technical field of preparation of ferrite materials. The method comprise the following steps: respectively preparing CoFe2O4 and SrFe12O19 nanopowder by virtue of a hydrothermal method, and then doping a small amount of SrFe12O19 nanopowder (mass ratio of 6%-10%) into the CoFe2O4 ferrite, evenly mixing, tabletting and sintering at a temperature of 700 DEG C-900 DEG C for 2 hours. According to the method, by virtue of the exchange coupling effect between the CoFe2O4 and SrFe12O19 nanocrystalline phases and the pinning effect of SrFe12O19 ferrite, the coercive force of the CoFe2O4 ferrite is significantly improved and the coercive force can be improved by 93% to a maximum extent. The method has important value for further practical application of the CoFe2O4 ferrite.

Description

technical field [0001] The invention belongs to the technical field of ferrite material preparation, and in particular relates to a method that can significantly improve spinel cobalt ferrite (CoFe 2 o 4 ) method of coercive force of permanent magnet material. Background technique [0002] Compared to common SrFe 12 o 19 and BaFe 12 o 19 Equihexagonal permanent magnet ferrite, permanent magnet CoFe with spinel structure 2 o 4 Ferrite theoretically has high saturation magnetization, but its coercive force is relatively low, which limits its application. Therefore, improving the permanent magnet CoFe 2 o 4 The coercive force of ferrite has important practical value. [0003] At present, there have been patents and literature published several different CoFe 2 o 4 Preparation method of ferrite. For example, the patent notification number CN1858003 discloses a water-soluble CoFe 2 o 4 A microwave synthesis method for nanocrystals; the patent with the notification ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/622C04B35/26
Inventor 夏爱林任素贞晋传贵吴胜华刘先国
Owner 安徽中马磁能科技股份有限公司
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