阅读说明：本技术 一种贫铁软磁铁氧体、电磁波吸收材料及其制备方法 (Lean-iron soft magnetic ferrite, electromagnetic wave absorption material and preparation method thereof ) 是由 颜冲 张建明 王育伟 于 2019-11-15 设计创作，主要内容包括：本发明涉及一种贫铁软磁铁氧体、电磁波吸收材料及其制备方法,它由主成分和副成分组成,以摩尔百分比计,所述主成分包括46.0~49.9mol%的Fe<Sub>2</Sub>O<Sub>3</Sub>、21.0~26.0mol%的ZnO以及余量的MnO；以主成分质量和为基准,所述副成分至少含有500~2500ppm的TiO<Sub>2</Sub>或1000-5000ppm的SnO<Sub>2</Sub>。通过采用特定组分的主成分和副成分进行复配,这样能够使得其做成的电磁波吸收材料在30MHz和500MHz频率的反射损耗都在20dB以上。(The invention relates to a lean-iron soft magnetic ferrite, an electromagnetic wave absorbing material and a preparation method thereof, wherein the lean-iron soft magnetic ferrite is composed of a main component and an auxiliary component, and the main component comprises 46.0-49.9 mol% of Fe in terms of mole percentage 2 O 3 21.0-26.0 mol% ZnO and the balance MnO; the subcomponent contains at least 500 to 2500ppm of TiO based on the mass sum of the principal components 2 Or 1000- 2 . By adopting the main component and the auxiliary component of the specific components for compounding, the reflection loss of the electromagnetic wave absorbing material prepared from the composite material at the frequencies of 30MHz and 500MHz is more than 20 dB.)

1. A lean-iron soft magnetic ferrite is composed of a main component and an auxiliary component, and is characterized in that: the main component comprises 46.0-49.9 mol% of Fe in terms of mol percentage₂O₃21.0-26.0 mol% ZnO and the balance MnO; based on the mass sum of the main components,the accessory component at least contains 500-2500 ppm TiO₂Or 1000-₂。

2. The lean soft magnetic ferrite of claim 1, wherein: the accessory ingredient also comprises 50-200 ppm of Na₂O。

3. The lean soft magnetic ferrite of claim 1, wherein: the accessory component also comprises 50-300 ppm of Ta₂O₅。

4. An electromagnetic wave absorbing material, characterized in that: it is composed of the low-iron soft magnetic ferrite as claimed in any one of claims 1 to 3.

5. An electromagnetic wave absorbing material as set forth in claim 1, wherein: its thickness is less than or equal to 6.5 mm.

6. A method for preparing an electromagnetic wave absorbing material as set forth in claim 4 or 5, characterized in that it comprises the steps of:

(a) weighing the main component and the auxiliary component in proportion, mixing, and presintering at 850-950 ℃ to obtain a presintering material;

(b) sanding and drying the pre-sintered material, adding a bonding agent, granulating, molding and sintering to obtain a sintered body;

(c) and (3) carrying out heat preservation sintering on the sintered body at 1250-1350 ℃.

7. The method for preparing an electromagnetic wave absorbing material as set forth in claim 6, wherein: in the step (b), the adhesive is polyvinyl alcohol, and the addition amount of the adhesive is 1wt% of the pre-sintering material.

8. The method for preparing an electromagnetic wave absorbing material as set forth in claim 6, wherein: in the step (b), the pre-sintering temperature is 900 ℃ and the time is 2 h; in the step (c), the sintering temperature is 1300 ℃ and the time is 5 h.

Technical Field

The invention belongs to the field of magnetic materials, relates to a soft magnetic ferrite, and particularly relates to a lean soft magnetic ferrite, an electromagnetic wave absorbing material and a preparation method thereof.

Background

With the continuous development of electronic information technologies such as 5G communication, people have an increasing demand for absorbing materials capable of absorbing electromagnetic waves. The absorption performance of the electromagnetic wave absorbing material can be evaluated by the reflection loss (ref (db)) calculated by the following equation:

in the above formula₀As wavelength (═ c/f), complex permeability is μ_r＝μ′_r-jμ″_rComplex dielectric constant of epsilon_r＝ε′_r_ε″_rAnd d is the thickness of the absorbing magnetic sheet. Generally speaking, the wave-absorbing material with reflection loss larger than 20dB and above under a given frequency band has excellent wave-absorbing performance; cost savings can be achieved by reducing the thickness of the absorbing magnetic flakes. The absorptive magnetic sheet is preferably relatively thin in thickness while maintaining reflection loss in a given frequency band.

MnZn ferrite and NiZn ferrite sintered materials can be used as the wave absorbing material. The NiZn ferrite material contains expensive Ni element, which increases the manufacturing cost of the material. The electromagnetic wave absorption sheet made of MnZn ferrite is inexpensive as compared with that made of NiZn ferrite, and can exert excellent absorption performance even when the thickness of the absorption sheet is thin. However, since the electromagnetic wave absorbing sheet made of MnZn ferrite is generally used only in a low frequency band of 30MHz or less, there is a need to develop a MnZn ferrite wave absorbing material that can realize excellent wave absorbing performance even at a frequency of 30MHz or more, particularly, in a frequency range of 30MHz to 500 MHz.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a lean soft magnetic ferrite.

In order to achieve the purpose, the invention adopts the technical scheme that: the lean-iron soft magnetic ferrite consists of a main component and an auxiliary component, wherein the main component comprises 46.0-49.9 mol% of Fe in terms of mole percentage₂O₃21.0-26.0 mol% ZnO and the balance MnO; the subcomponent contains at least 500 to 2500ppm of TiO based on the mass sum of the principal components₂Or 1000-₂。

Optimally, the accessory ingredient also comprises 50-200 ppm of Na₂O。

OptimizationThe accessory component also comprises 50-300 ppm of Ta₂O₅。

It is still another object of the present invention to provide an electromagnetic wave absorbing material composed of the above lean soft magnetic ferrite. The electromagnetic wave absorbing material can be in a conventional sheet shape and the like, and the thickness of the electromagnetic wave absorbing material is less than or equal to 6.5 mm.

Another object of the present invention is to provide a method for preparing an electromagnetic wave absorbing material, which comprises the steps of: (a) weighing the main component and the auxiliary component in proportion, mixing, and presintering at 850-950 ℃ to obtain a presintering material; (b) sanding and drying the pre-sintered material, adding a bonding agent, granulating, molding and sintering to obtain a sintered body; (c) and (3) carrying out heat preservation sintering on the sintered body at 1250-1350 ℃. In the step (b), the adhesive is polyvinyl alcohol, and the addition amount of the adhesive is 1wt% of the pre-sintering material. In the step (b), the pre-sintering temperature is 900 ℃ and the time is 2 h; in the step (c), the sintering temperature is 1300 ℃ and the time is 5 h.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages: according to the lean-iron soft magnetic ferrite, the main component and the auxiliary component with specific components and contents are compounded, so that the reflection loss of the electromagnetic wave absorbing material prepared from the lean-iron soft magnetic ferrite at the frequencies of 30MHz and 500MHz is more than 20 dB.

Detailed Description

The lean-iron soft magnetic ferrite comprises a main component and an auxiliary component, wherein the main component comprises 46.0-49.9 mol% of Fe in terms of mole percentage₂O₃21.0-26.0 mol% ZnO and the balance MnO; the subcomponent contains at least 500 to 2500ppm of TiO based on the mass sum of the principal components₂Or 1000-₂. By adopting the main component and the auxiliary component with specific components and contents for compounding, the electromagnetic wave absorbing material prepared from the composite material can generate a composite effect, and the reflection loss at the frequency of 30MHz and 500MHz is more than 20 dB. The accessory ingredient also comprises 50-200 ppm of Na₂O, which is easy to form a glass phase existing in a grain boundary and is beneficial to improving the sintering density; the accessory ingredient also comprises 50-300 parts ofTa of ppm₂O₅Thus, the crystal grains can be refined and the growth of the crystal grains can be promoted to be uniform. The abovementioned secondary components may also contain other impurities, particularly added or unavoidable, generally in the range from a few ppm to a few hundred ppm, such as SiO, relative to the mass sum of the main component₂、CaO、NiO、MgO、Al₂O₃、Cr₂O₃、P₂O₅、B₂O₃、SO₃One or more of CuO, and the like; they have little effect on the final electromagnetic wave absorbing material.

The electromagnetic wave absorbing material of the present invention is composed of the above-mentioned lean soft magnetic ferrite. The electromagnetic wave absorbing material can be in a conventional sheet shape, and the thickness of the electromagnetic wave absorbing material can be selected according to actual needs, such as less than or equal to 10mm, and further can be selected to be less than or equal to 6.5 mm. The preparation method of the electromagnetic wave absorbing material comprises the following steps: (a) weighing the main component and the auxiliary component in proportion, mixing, and presintering at 850-950 ℃ to obtain a presintering material; (b) sanding and drying the pre-sintered material, adding a bonding agent, granulating, molding and sintering to obtain a sintered body; (c) and (3) carrying out heat preservation sintering on the sintered body at 1250-1350 ℃. In the step (b), the adhesive is polyvinyl alcohol, and the addition amount of the adhesive is 1wt% of the pre-sintering material. In the step (b), the pre-sintering temperature is 900 ℃ and the time is 2 h; in the step (c), the sintering temperature is 1300 ℃ and the time is 5h

(the sintering temperature range described above does not greatly affect the properties of the product).

The following detailed description of preferred embodiments of the invention is provided: