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Preparation method of M-type calcium permanent magnetic ferrite

A permanent magnet ferrite and ferrite technology, applied in the field of permanent magnet materials, can solve the problems of magnetic performance limitation, long secondary ball milling time, coercive force and squareness ratio limitation, etc., to reduce the sintering temperature and ensure comprehensive magnetic properties Can effect

Active Publication Date: 2014-12-24
江门江益磁材有限公司
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  • Description
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Problems solved by technology

[0007] In order to improve and eliminate the reduction of magnetic properties caused by the deterioration of the calcined microstructure, many scholars have adjusted the particle size of the doped LaCo compound to regulate the microscopic morphology of the calcined material, thereby improving the magnetic properties. Although there has been some progress, but Since the traditional muffle furnace is still used for pre-firing in the preparation process, it is difficult to make improvements in reducing the grain size, which leads to a longer time for the second ball milling and a wider particle size distribution after the second ball milling, thus The improvement of the final magnetic properties is limited, especially the improvement of coercive force and squareness ratio is limited

Method used

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  • Preparation method of M-type calcium permanent magnetic ferrite
  • Preparation method of M-type calcium permanent magnetic ferrite
  • Preparation method of M-type calcium permanent magnetic ferrite

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preparation example Construction

[0040] Please refer to figure 1 , figure 1 The flow chart of the preparation method of the M-type calcium permanent magnet ferrite that the embodiment of the present invention provides, such as figure 1 Shown, the preparation method of the M type calcium permanent magnet ferrite provided by the invention comprises the steps:

[0041] S1. Ingredients: according to chemical structural formula A 1-x-y Ca x R y Fe 2n-z m z o 19 The composition requires the preparation of main material powder; add additive H by weight percentage 3 BO 3 , SiO 2 , CaCO 3 , La 2 o 3 、Co 3 o 4 and SrCO 3 , each component accounts for A 1-x-y Ca x R y Fe 2n-z m z o 19 The weight percentage is 0≤H 3 BO 3 ≤0.5%, 0≤SiO 2 ≤1.0%, 0.1%≤CaCO 3 ≤1.2%, 0≤La 2 o 3 ≤1.0%, 0≤Co 3 o 4 ≤1.0%, 0≤SrCO 3 ≤0.8%; and mixing and stirring the main material powder and the additive into a material powder;

[0042] S2, one-time ball milling: put the powder into the ball mill for grinding, add ste...

Embodiment 1

[0057] In this embodiment, the main phase of the M-type calcium permanent magnet ferrite is: Sr 0.72 Ca 0.05 La 0.23 Fe 11.21 co 0.19 o 19 , its preparation method is:

[0058] The batching process selects the raw materials of main ingredients as follows:

[0059] Fe 2 o 3 powder (of which Fe 2 o 3 The purity of the powder ≥ 99.3wt%, the original average particle size of the particles: 0.75um) 84.48wt%;

[0060] SrCO 3 Powder (purity ≥ 99%, original average particle size of particles: 1.0um) 10.06wt%;

[0061] La 2 o 3 Powder (purity ≥ 99%, original average particle size of particles: 2.0um) 3.55wt%;

[0062] co 3 o 4 Powder (purity ≥ 99.3%, original average particle size of particles: 0.8um) 1.44wt%;

[0063] CaCO 3Powder (purity ≥ 99.9%, original average particle size of particles: 2um) 0.47wt%;

[0064] The additives selected in the batching process are as follows:

[0065] h 3 BO 3 , SiO 2 , CaCO 3 , La 2 o 3 、Co 3 o 4 and SrCO 3 , each compone...

Embodiment 2

[0086] The raw material selection is the same as in Example 1, except that microwave pre-firing is divided into primary pre-firing and secondary pre-firing. Among them, the primary pre-firing is microwave pre-firing, and the second pre-firing uses a traditional muffle furnace for pre-firing.

[0087] The pre-firing temperature of the primary pre-firing is 1150°C, and the holding time is 30 minutes. The temperature of the secondary pre-burning is 1150°C, and the holding time is 90 minutes; the main phase formula with ferrite can be expressed as: Sr 0.72 Ca 0.05 La 0.23 Fe 11.21 co 0.19 o 19 .

[0088] Subsequent process is substantially the same as embodiment 1;

[0089] Randomly extract three samples in the samples of a plurality of sintered permanent magnet ferrites obtained in embodiment 2 and carry out upper and lower surface grinding, measure its residual magnetic induction (B r ), coercive force (H cb ), internal coercive force (Hcj), maximum energy product (BH) ...

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Abstract

The invention discloses a preparation method of an M-type calcium permanent magnetic ferrite. The M-type calcium permanent magnetic ferrite has the following molecular formula: A<1-x-y>CaxRyFe2n-zMzO19. According to the preparation method, a drying step and a microwave pre-sintering step are set before a sintering step, and the microwave pre-sintering step can be further subdivided into a primary pre-sintering step and a secondary pre-sintering step, wherein a microwave pre-sintering way is adopted in the primary pre-sintering step and / or the secondary pre-sintering step. Due to the setting of two-step sintering, a material can completely react at a pre-sintering state. Due to the introduction of the microwave pre-sintering way in the pre-sintering step, completely-reacted uniform and fine crystal grains are expected to obtain. Therefore, on one hand, the pre-sintered material has good performance, on the other hand, the secondary ball milling difficulty can be lowered, impurities brought by secondary ball milling and the particle size distribution range widening phenomenon caused by long-time ball milling can be reduced, and furthermore the comprehensive magnetic performance of the finally-obtained product can be improved.

Description

technical field [0001] The invention relates to the technical field of permanent magnet materials, in particular to a preparation method of M-type calcium permanent magnet ferrite. Background technique [0002] According to its characteristics and uses, ferrite is generally divided into five categories: permanent magnet, soft magnet, moment magnet, gyromagnetic and compressed ferrite. [0003] The final magnetic properties of permanent ferrite are generally measured by remanence Br and intrinsic coercive force Hcj. Among them, the high-performance permanent magnet ferrite usually refers to the ferrite that has the advantages of high residual magnetic induction, strong anti-demagnetization performance and low manufacturing cost. Due to these advantages, high-performance permanent ferrites are widely used in industries such as electronics, information, motorcycles, automobiles, and electric tools. [0004] The traditional ferrite material used in large quantities is Sr ferri...

Claims

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Application Information

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IPC IPC(8): C04B35/40C04B35/622
Inventor 汪南东陈中艳王凡冯则坤吕兆民
Owner 江门江益磁材有限公司
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