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Anti-EMI (electromagnetic interference) ferrite material and preparation method thereof

A ferrite material and main component technology, applied in the field of anti-EMI ferrite material and its preparation, can solve the problems of low impedance, low impedance value, high impedance value, etc., achieve strong adaptability of raw materials, reduce electromagnetic wave interference, Effect of Excellent Impedance Characteristics

Inactive Publication Date: 2015-01-07
麦格磁电科技(珠海)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

From the examples, the magnetic core obtained by this technical scheme has a magnetic permeability of 1M below 2000; at the same time, the document does not give the data of the volume resistivity, and the formula main component Fe used in it is Fe 2 o 3 If the content exceeds 50mol%, its volume resistivity generally cannot reach 100Ωm, and the impedance will be low at high frequencies (above 5M)
[0010] There are two types of existing anti-EMI ferrite materials: one is Fe in the composition 2 o 3 Manganese-zinc ferrite materials with more than 50mol% have high initial magnetic permeability, which can reach 5000 and above, and have high impedance in the frequency range of 100K to 5M, but due to the Fe in its formula 2 o 3 The content exceeds 50 moles, and the volume resistivity is low, resulting in a frequency above 5M, and the impedance value is low; one is nickel-zinc or magnesium-zinc ferrite whose iron oxide is less than 50mol% in composition, and its initial magnetic permeability is low, often Below 2000, in the frequency range of 100K to 5M, the impedance value is low, but because of the iron deficiency formula, its volume resistivity is as high as 10000Ωm and above, and when the frequency is 25M and higher, its impedance value is high

Method used

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  • Anti-EMI (electromagnetic interference) ferrite material and preparation method thereof

Examples

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preparation example Construction

[0045] The preparation method of above-mentioned anti-EMI ferrite material, comprises the following steps:

[0046] (1) Mixing treatment: Weigh the main component raw materials in proportion, and mix them in a vibration mill for 20-120 minutes;

[0047] (2) Pre-sintering treatment: the mixed material is pre-sintered at 700-1200°C for 30-180 minutes;

[0048] (3) Sanding treatment: Add auxiliary components and additives weighed in proportion to the pre-fired powder, and sand for 30-150 minutes, so that the D50 is between 1.0-1.75 μm;

[0049] (4) Spray granulation;

[0050] (5) Molding treatment;

[0051] (6) Sintering treatment: The blank obtained after molding is sintered in an atmosphere with an oxygen content of 100ppm-21.00% (air), wherein the sintering temperature is 1200-1450°C, and the sintering holding time is 1-15 hours. The ferrite material can be obtained by cooling the saturated atmosphere to room temperature.

[0052] Step (4) spray granulation is to obtain pa...

Embodiment 1

[0058] According to the ratio of Fe 2 o 3 44.0mol%, ZnO 17.0mol%, MnO 39.0mol% Weigh the main component raw materials, mix them in a vibration mill for 20 minutes, then pre-burn at 700°C for 180 minutes, add the auxiliary component CoO ( 3000ppm), ammonium citrate 100ppm, polyvinyl alcohol glue 5wt%, octanol 2000ppm, sand mill for 30 minutes to obtain a slurry with a particle size D50 of 1.75 μm, and then spray granulate to obtain ferrite powder. Use a fully automatic hydraulic press to press the powder into a rough sample of H38×19×13, keep it warm at 1450°C with an oxygen content of 21% for 1 hour, and cool it down to room temperature in a nitrogen-saturated atmosphere to obtain a ferrite core. The sample number is 1. The initial permeability and volume resistivity test results of the sample are shown in Table 1, and the impedance and frequency f curves are shown in figure 1 , figure 2 or image 3 shown.

Embodiment 2

[0060] According to the ratio of Fe 2 o 3 44.0mol%, ZnO 24.0mol%, MnO 32.0mol% take the main component raw materials, mix in the vibration mill for 120 minutes, then pre-burn at 1200 ° C for 30 minutes, add the auxiliary component CoO ( 20000ppm) and ammonium citrate 2000ppm, polyvinyl alcohol glue 5wt%, grind for 150 minutes to obtain a slurry with a particle size D50 of 1.0 μm, and then spray granulate to obtain ferrite powder. Press the powder into a blank sample of H38×19×13 with a fully automatic hydraulic machine, keep it warm at 1200°C for 15 hours at an oxygen content of 100ppm, and cool it down to room temperature in a nitrogen-saturated atmosphere to obtain a ferrite core. The sample number is 2. The test results of initial magnetic permeability and volume resistivity are shown in Table 1.

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Abstract

The invention discloses an anti-EMI (electromagnetic interference) ferrite material and a preparation method thereof. The initial permeability of the ferrite material provided by the invention at the normal temperature is over 2000, the volume resistivity is over 100 ohm, and the ferrite material has an excellent impedance characteristic in a frequency band of 1-100M and can be used for effectively reducing electromagnetic wave interference of electronic equipment. The anti-EMI ferrite material disclosed by the invention can be produced and prepared by adopting conventional equipment and is simple in process, low in energy consumption and strong in adaptability of raw materials.

Description

technical field [0001] The invention belongs to the field of soft magnetic anti-EMI (Electromagnetic Interference, EMI for short), and specifically relates to a ferrite material for anti-EMI with high initial magnetic permeability and high volume resistivity and a preparation method thereof. Background technique [0002] With the increasing development of electronic technology, especially the rapid development of digital technology. All countries in the world attach great importance to the ability of electronic equipment to resist EMI. How to effectively reduce the electromagnetic wave interference of electronic equipment has become a common concern of researchers. Various EMI suppression components made of soft ferrite are widely used in various electronic devices to prevent unwanted signal feedback and coupling, avoid parasitic oscillations, and effectively suppress conduction and radiation noise. [0003] Impedance values ​​produced by ferrite: [0004] Z F = R + jω,...

Claims

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Application Information

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IPC IPC(8): C04B35/26C04B35/622
Inventor 毕建国刘志坚
Owner 麦格磁电科技(珠海)有限公司
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