磁导率与厚度因素对磁屏蔽效能的影响

Influence of Permeability and Thickness on Magnetic Shielding Effect

利用漏磁通法并选取取向硅钢及内磁屏蔽钢进行了磁屏蔽效能实验。对取向硅钢而言,随外磁场强度增加,材料屏蔽效能(SE)先是急剧上升至18.1dB,达到极大值后再缓慢下降。根据趋近于直流状态的磁导率在达到极大值前,材料屏蔽效能(SE)相似于磁导率变化趋势,证实材料尚未饱和;达到极大值后的缓慢变化应当根据取向硅钢磁化时磁力线的填充规则说明。对取向硅钢单片、双片以及不同厚度内磁屏蔽钢进行了比对实验,证实同种材料在材料磁化到饱和后,屏蔽效能的影响与厚度呈等趋势变化。

The paper presents a brief introduction to magnetic shielding material and shielding principle. The leaking magnetic flux density method was used to inspect magnetic shielding effect. With the increase of magnetic field strength, shielding effect （SE） increased abruptly and then decreased slowly. Classic shielding effect formula was applied to explain the phenomenon according to the permeability tending toward DC. To illuminate the influence of material thickness on shielding effect, oriented silicon steel （sin- gle sheet and double sheet） and inner magnetic shielding steel of different thickness were tested. It was proved that after the magnetic saturation, magnetic shielding effect varied proportionally with the thickness.