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Low frequency strong magnetic field shield material

A shielding material and strong magnetic field technology, applied in the fields of magnetic/electric field shielding, electrical components, layered products, etc., can solve the problems of difficult shielding, reduced shielding efficiency, and unsatisfactory shielding effect of low-impedance magnetic field waves, and achieves improved anti-low frequency The ability of strong magnetic field interference and the effect of improving shielding effectiveness

Inactive Publication Date: 2013-06-26
GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the radiation field of the interference source belongs to the characteristics of low voltage and high current, its electromagnetic wave radiation field is mainly manifested as a low-frequency strong magnetic field. Although high-frequency materials such as copper have a good shielding effect on electric fields and high-frequency electromagnetic fields above 500KHz, the shielding effect on such low-impedance magnetic field waves is not ideal; on the other hand, although magnetic materials can be used to shield magnetic fields, they are not In fact, the magnetic permeability of the material is a function of the magnetic field frequency and magnetic field strength, and it will decrease with the increase of the magnetic field frequency, especially when the magnetic field strength is very high, the magnetic permeability of the magnetic permeable material decreases sharply and enters a magnetic saturation state , thus reducing the shielding efficiency

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] First prepare a PVA cylindrical tube according to the technical scheme described in the summary of the invention, then coat the outer wall with a layer of 0.1mm thick 1J85 ferromagnetic strip, and finally coat the outermost layer of the test sample with a layer of aluminum foil with a thickness of 0.03mm. The heat treatment process of ferromagnetic materials is: vacuum atmosphere, heat treatment temperature 1180°C, heat preservation for 4 hours, then cooling to 600°C in 3 hours, filling with argon gas at a cooling rate of 500°C / h to quickly cool to 150°C out of the furnace. Put the sample in a uniform magnetic field to test its shielding performance. The frequency of the magnetic field ranges from 10KHz to 500KHz, and the magnetic field strength ranges from 2.3Gs to 0.3Gs. Test results such as figure 2 As shown, the shielding effectiveness of the material is less than 40dB at 10KHz, and greater than 40dB above 20KHz.

Embodiment 2

[0038] First, prepare a PVA cylindrical tube according to the technical scheme described in the summary of the invention, then coat the outer wall with a layer of 1J50 ferromagnetic strip with a thickness of 0.1mm, and finally coat the outermost layer of the test sample with a layer of aluminum foil with a thickness of 0.03mm. The heat treatment process of ferromagnetic materials is: vacuum atmosphere, heat treatment temperature 1150°C, heat preservation for 5 hours, then cooling to 600°C in 3 hours, filling with argon gas at a cooling rate of 400°C / h to quickly cool to 150°C out of the furnace. Put the sample in a uniform magnetic field to test its shielding performance. The frequency of the magnetic field ranges from 10KHz to 500KHz, and the magnetic field strength ranges from 2.3Gs to 0.3Gs. Test results such as image 3 As shown, the shielding effectiveness of the material is less than 40dB at 10KHz-30KHz, and greater than 40dB above 40KHz.

Embodiment 3

[0040]First prepare the PVA cylindrical tube according to the technical scheme described in the summary of the invention, then respectively paste a layer of 0.05mm thick 1J79 and 0.1mm thick 1J50 ferromagnetic strips on the outer wall, and finally between the ferromagnetic strips and between the test samples The outermost layer is covered with a layer of aluminum foil with a thickness of 0.03mm. The heat treatment process of 1J79 ferromagnetic material is: vacuum atmosphere, heat treatment temperature 1180°C, heat preservation for 4 hours, then cooling to 600°C in 3 hours, filling with argon gas at a cooling rate of 500°C / h to quickly cool to 150°C out of the furnace. The heat treatment process of 1J50 ferromagnetic material is: vacuum atmosphere, heat treatment temperature 1150°C, heat preservation for 5 hours, then cooling to 600°C in 3 hours, filling with argon gas at a cooling rate of 400°C / h to quickly cool to 150°C out of the furnace. Put the sample in a uniform magnetic...

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Abstract

The invention relates to a low frequency strong magnetic field shield material, which is composed of a single layer or multiple layers high conductivity material and a ferromagnetism material. The shield material is combined by the high conductivity material and the ferromagnetism material according to different orders, layers and thicknesses. The ferromagnetism material is performed with heat processing during the process for preparing the shield material. Considering the easy generation of magnetic saturation phenomenon of high magnetic permeability ferromagnetism material under strong magnetic field environment, a highly resistance magnetic saturation material is selected to reduce the strong magnetic field, then the high magnetic permeability material is employed to shield attenuated magnetic field, The high conductivity material is employed as a magnetic barrier layer between the highly resistance magnetic saturation material and the high magnetic permeability material layer, and the low frequency strong magnetic field shield material can partially shield the alternating magnetic field. According to the invention, the thickness of the shield material is about 0.2mm, the shield efficiency of the low frequency strong magnetic field at 10 kHz-500 kHz can reach 40 dB, and a technical problem that how to increase the shield efficiency of the low frequency strong magnetic field under the condition that the shield material allowanced thickness is limited can be solved.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic shielding, in particular to the shielding of low-frequency strong magnetic fields. The frequency range of the magnetic field is 10KHz-500KHz, and the magnetic field strength range is 2.3Gs-0.3Gs. Background technique [0002] Electronic equipment, instruments, etc. are easily disturbed by the electromagnetic field of the surrounding environment during the working process. In order to ensure the normal operation of electronic equipment, instruments and meters, they need to be electromagnetically shielded. If the radiation field of the interference source belongs to the characteristics of low voltage and high current, its electromagnetic wave radiation field is mainly manifested as a low-frequency strong magnetic field. Although high-frequency materials such as copper have a good shielding effect on electric fields and high-frequency electromagnetic fields above 500KHz, the shielding effect...

Claims

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Application Information

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IPC IPC(8): B32B15/01H05K9/00
Inventor 马书旺杨剑毛昌辉刘坤梁秋实
Owner GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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