Insulation coating method of composite soft magnetic powder

Abstract

The invention discloses an insulation coating method for composite soft magnetic powder. The insulation coating method comprises the steps of: S1, screening soft magnetic alloy powder; S2, uniformly dispersing the soft magnetic ferrite fine powder into an ethanol solution of a silane coupling agent to obtain a first dispersion liquid; S3, adding magnetically soft alloy powder into the first dispersion liquid for pretreatment; S4, adding ammonia water and tetraethoxysilane into the composite powder dispersion liquid to generate a composite coating layer; S5, dissolving a binder and a lubricant in acetone, and uniformly dispersing the ferrite fine powder in the solution to obtain a second dispersion liquid; and S6, evenly mixing the coated magnetically soft alloy powder into the second dispersion liquid, and conducting granulation and drying. The insulation coating method has the beneficial effects that a proper amount of soft magnetic ferrite fine powder is doped in the silicon dioxide coating layer and the binder, so that the magnetic conductivity of a magnetic part formed by pressing is improved, meanwhile, the high-frequency loss is relatively low, and a rear-end device has more excellent comprehensive performance.

Description

technical field [0001] The invention relates to the field of magnetic materials, in particular to an insulation coating method of composite soft magnetic powder. Background technique [0002] Amorphous and nanocrystalline soft magnetic materials have excellent properties such as high saturation magnetization, high magnetic permeability, low coercive force, low loss, good hardness, wear resistance and corrosion resistance, good temperature and environmental stability, etc. Comprehensive performance, in power electronics technology, embodies the advantages of small size, high efficiency, energy saving, etc., and its performance and price are relatively good among all metal soft magnetic materials. [0003] In the preparation process of amorphous and nanocrystalline magnetic powder cores, the performance of the insulating coating layer is an important factor affecting the high-frequency loss of the magnetic powder core. If the insulating coating layer is incomplete or damaged, ...

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Problems solved by technology

At present, the preparation of most magnetic powder cores is mainly made of inorganic coatings. Although these coatings have good insulation effects, most of them are non-magnetic substances, thus greatly reducing the magnetic properties of the magnetic powder cores.

[0004] In the application of the prior art, the insulation coating process usually uses an acidic solution for corrosive insulation coating treatment, such as disclosed in patent documents such as CN110181036A and CN104078180B Phosphoric acid solution is used to passivate the powder, and then insulating agent and binder are added for powder insulation coating. The acidic solution is usually diluted by volatile organic compounds, resulting in increased cost and environmental damage; reaction control in the corrosion process It is more difficult, and it is prone to uneven coating and excessive local heat release of powder particles, resulting in changes in the amorphous and nanocrystalline structure of the powder particle surface; corrosion of powder particles will cause adverse consequences such as a decrease in powder magnetic permeability and an increase in hysteresis loss , so in view of the above problems, it is urgent to design an insulation coating method of composite soft magnetic powder to meet the needs of actual use

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