Composite electromagnetic shielding material for cables

Abstract

The invention provides a composite electromagnetic shielding material, belonging to the power electronic field. The composite electromagnetic shielding material is mainly made of electromagnetic shielding filler and thermoplastic plastic, wherein the mass ratio of the electromagnetic shielding filler to the thermoplastic plastic is (30-60):(70-40). The electromagnetic shielding filler refers to conductive carbon composite micro-sphere grains of which the surface is wrapped with Zn2-W type ferrite. The filler and the thermoplastic plastic are obtained by mixing, milling, extruding and prilling; the material can be used for manufacturing shells or shielding layers of power electric appliances; and meanwhile the material has strong shielding and absorbing efficiency.

Description

technical field [0001] The invention relates to an electromagnetic shielding material used in the field of power electronics, which can effectively shield cables, electrical appliances and electromagnetic waves generated inside and outside of electronic components. Background technique [0002] Electromagnetic Compatibility (EMC) refers to the performance of an electronic device that neither interferes with nor is not affected by other devices. With the development of the power electronics industry and the improvement of people's requirements for product quality and safety, electromagnetic compatibility has become an important indicator of product quality. The main means to achieve electromagnetic compatibility is electromagnetic shielding, that is, to isolate the electromagnetic field between two space regions to control the induction and radiation of electric fields, magnetic fields and electromagnetic waves from one region to another. Specifically, it is to use shielding ...

AI Technical Summary

Problems solved by technology

Hexagonal M-type strontium ferrite is a very important type of electromagnetic wave absorber. Its natural resonance frequency is high, it is not easy to generate skin current at high frequency, and its dielectric constant is small. It can be used in combination with other absorbing materials. Adjust the electromagnetic parameters of the wave-absorbing coating. However, the disadvantage is that the process is difficult to prepare, and a slight change in the process will affect the wave-absorbing performance. At the same time, it is necessary to improve the magnetic permeability of a single M-type ferrite , the difficulty is relatively large

If ferromagnetic metal powder absorbents with higher magnetic permeability are used, although they have good temperature stability and higher saturation magnetization Ms, these ferromagnetic metal powder absorbents are limited in the microwave frequency band due to the "tendency "skin effect" and the particle size should not be too large, and it is required to be evenly distributed, and the volume fraction should not be too large, so it also limits the increase of its filling amount

In addition, ferromagnetic metal materials also have a large specific defect

[0007] Therefore, in the shielding material, whether it is a single use of ferrite or ferromagnetic metal materials or a simple combination of them, it is impossible to obtain a shielding material with light weight, high filling, and good shielding effectiveness.

Images