Preparation method of biphase composite hard magnetic ferrite with exchange coupling

A technology of hard ferrite and exchange coupling, applied in the field of preparation of two-phase composite hard ferrite, can solve problems such as unfavorable exchange coupling effect, achieve fine and uniform powder, good exchange coupling characteristics, reduce sintering temperature and energy. consumption effect

Active Publication Date: 2013-12-18
ANHUI SINOMAG TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, the use of oxide methods that require high-temperature sin

Method used

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  • Preparation method of biphase composite hard magnetic ferrite with exchange coupling
  • Preparation method of biphase composite hard magnetic ferrite with exchange coupling
  • Preparation method of biphase composite hard magnetic ferrite with exchange coupling

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Experimental program
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Effect test

Embodiment 1

[0027] Preparation of SrFe 12 o 19 Powder: to analyze pure nitrate Sr(NO 3 ) 2 , Fe(NO 3 ) 3 Prepare 2 mmol of SrFe as starting material 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, 84mmol NaOH is required. The nitrate raw material was dissolved in 45 ml deionized water, and the NaOH was dissolved in 30 ml deionized water. Then, add NaOH solution dropwise to the mixed nitrate solution while stirring to make the metal ion precipitate, move the precipitate and the precipitate into a 100ml hydrothermal reaction kettle for hydrothermal reaction, and control the filling degree of the reactor to be 80% at the same time, and the reaction conditions are 220 °C×5h. The powder obtained after the reaction was washed 3 times and 2 times with deionized water and absolute ethanol, respectively. To ensure the purity of the phase, the obtained Sr f...

Embodiment 2

[0032] The preparation method of composite ferrite is the same as embodiment 1, and the variable parameter is: the SrFe that will prepare 12 o 19 and Ni 0.4 Zn 0.6 Fe 2 o 4 The nano powder is pressed into discs according to the mass ratio of 2:1. Crystal structure tests showed that the sample indeed contained only SrFe 12 o 19 and Ni 0.4 Zn 0.6 Fe 2 o 4 two phases. Figure 5 The hysteresis loop diagrams of the samples tested by VSM are given in . As can be seen from the figure, containing SrFe 12 o 19 and Ni 0.4 Zn 0.6 Fe 2 o 4 The two-phase composite ferrite powder sample does not show a step-type or neck-type two-phase characteristic curve, but a good single-phase hard magnetic characteristic curve, which indicates that there is good exchange coupling in the sample.

Embodiment 3

[0034] The preparation method of composite ferrite is the same as embodiment 1, and the variable parameter is: the SrFe that will prepare 12 o 19 and Ni 0.4 Zn 0.6 Fe 2 o 4 The nano powder is pressed into discs according to the mass ratio of 1:2. from Figure 5 The hysteresis loop in the figure shows that the composite ferrite exhibits a single-phase hard magnetic characteristic curve, which indicates that there is a good exchange coupling in the sample.

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Abstract

The invention discloses a preparation method of a biphase composite hard magnetic ferrite with hard magnetic/soft magnetic exchange coupling, belonging to the technical field of preparation of magnetic ferrites. The method comprises the following steps: pressing acid-cleaned SrFe12O19 and NixZn1-xFe2O4 ferrite nanopowder independently prepared by a hydrothermal method into wafers according to a certain weight ratio; then, calcining the wafers for 2 hours at 700 DEG C, wherein the biphase ferrite externally shows a single phase magnetic behavior, namely an exchange coupling effect exists. With the adoption of the method, as the required ferrite phase is directly prepared at a low temperature by the hydrothermal method, the phase forming problem doesis not needed to be considered when the ferrite is sintered at a high temperature into blocks. The grains of the powder are fine and uniform, so that the ferrite can be sintered into compact blocks at a lower temperature, thereby facilitating reduction of sintering temperature and energy consumption of the blocks. The grain of the ferrite which is calcined for 2 hours at 700 DEG C is still about 20nm, thereby facilitating formation of the exchange coupling effect.

Description

technical field [0001] The invention relates to the technical field of preparation of magnetic ferrite, in particular to a preparation method of a two-phase composite hard ferrite with hard magnetic / soft magnetic exchange coupling. Background technique [0002] As a ferrimagnetic material with a long history, hard ferrite is still widely used in electronics, home appliances, automobiles and other industries due to its high cost performance, cheap raw materials and good chemical stability. It is currently one of the magnetic materials with the largest output. one. However, as a big country in the production of hard ferrite, China's production technology is much behind that of Europe, America and Japan, and there is still a long way to go before becoming a strong country in the production of hard ferrite. For this reason, it is urgent to find a new preparation method of hard ferrite to improve the production level of hard ferrite in our country. [0003] Experiments and theo...

Claims

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Application Information

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IPC IPC(8): C04B35/26C04B35/30C04B35/622C04B35/626H01F1/10
Inventor 夏爱林左从华晋传贵吴胜华胡绪照任素贞
Owner ANHUI SINOMAG TECH
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