은 피복 Ni-Zn Ferrite 분말이 혼입된 고무 복합재의 전자파 차폐효과 (Electromagnetic Shield Effectiveness of Rubber Composites Containing Ag-coated Ni-Zn Ferrite Particles)

서지정보

· 발행기관 : 대한금속·재료학회
· 수록지 정보 : 대한금속·재료학회지 / 53권 / 1호 / 59 ~ 65페이지
· 저자명 : 김종혁, 김성수

초록

The present investigation provides an electromagnetic shielding composition that comprises Ag-coated Ni-Zn ferrite microspheres dispersed in silicon rubber matrix. Shielding effectiveness is analyzed for both the far-field and the near-field on the basis of electromagnetic shielding theory. Ni-Zn ferrite spheres that were 50 μm size on average were prepared by spray drying and sintering at 1130 ℃. Ag layer was plated on the ferrite spheres by electroless plating. Conductive Ni-Zn ferrite spheres with uniform Ag layer were obtained through plating using a high concentration of Ag precursor. The most sensitive material parameters of the rubber composites containing the ferrite spheres with Ag plating are the high values of the real and imaginary parts of the complex permittivity. The space charge polarization between the conductive particles in the rubber matrix results in high values of the dielectric constant and dielectric loss. Due to the high dielectric constant of the composites, a high value of the shielding effectiveness is predicted for the electric field. However, the shielding effectiveness for the magnetic field is not very high due to the small magnetic permeability of the ferrite spheres.

영어초록

The present investigation provides an electromagnetic shielding composition that comprises Ag-coated Ni-Zn ferrite microspheres dispersed in silicon rubber matrix. Shielding effectiveness is analyzed for both the far-field and the near-field on the basis of electromagnetic shielding theory. Ni-Zn ferrite spheres that were 50 μm size on average were prepared by spray drying and sintering at 1130 ℃. Ag layer was plated on the ferrite spheres by electroless plating. Conductive Ni-Zn ferrite spheres with uniform Ag layer were obtained through plating using a high concentration of Ag precursor. The most sensitive material parameters of the rubber composites containing the ferrite spheres with Ag plating are the high values of the real and imaginary parts of the complex permittivity. The space charge polarization between the conductive particles in the rubber matrix results in high values of the dielectric constant and dielectric loss. Due to the high dielectric constant of the composites, a high value of the shielding effectiveness is predicted for the electric field. However, the shielding effectiveness for the magnetic field is not very high due to the small magnetic permeability of the ferrite spheres.

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