Study On The Electromagnetic Shielding Properties Of Fe-based Amorphous Alloy

With the development of information technology and electronic industry, electromagnetic wave radiation has already being a new public hazard. Exploring effective electromagnetic shielding composites, preventing electromagnetic radiation pollution to protect the environment and human health, preventing electromagnetic leakage in order to ensure the security of information, has become the international problem that need to be addressed urgently.In this paper, the electromagnetic shielding characteristics of FeSiB amorphous strips and powders, have been studied in detail. For the FeSiB amorphous powder and FeCuNbSiB nanocrystalline powder, E51 typed epoxy resin is selected as the matrix of electromagnetic shielding composite, and the glass fiber and carbon fiber were selected as the reinforced phase. The series of electromagnetic shielding composite panels with the thickness from lmm to 5mm were prepared successfully with excellent mechanical properties and shielding properties by controlling the processing parameter of string technology, solidifying pressure and temperature, etc. strictly. Otherwise, for the iron-based FeSiB amorphous strip, butyl rubber (IIR) is choose as the matrix and carbon fiber is as reinforced materials to prepare the IIR/Cf composite film, and then the electromagnetic shielding composites is formed by sticking amorphous strips on the prepared IIR/Cf composite film surface. Through tesing, the shielding properties during the range of 1MHz～1.5GHz were analysed systematically.It is shown that the tensile strength, fracture strength and elongation at break are all improved with the increasing content of Fe-based FeSiB amorphous powder and FeCuNbSiB nanocrystalline powder. Comparing with the E-type glass fiber composite with the tensile strength greater than 100MPa and the compression strength more than 200MPa, the tensile strength of the S-type glass fiber composite is above 680MPa. During the electromagnetic wave band range from 30kHz to 6GHz, the composite panels with Fe-based FeSiB amorphous powder and FeCuNbSiB nanocrystalline powder as shielding agents show a good high-frequency shielding characteristics and broadband shielding characteristics, and the shielding properties of the composite is rising significantly with the powder content and material thickness increasing. Meanwhile, the absolute value of shielding effectiveness decreased from about 50dB to about 13dB at the range of 30 kHz-0.2 GHz. At the same time, the absolute value of shielding effectiveness is above 13dB, and the absolute value increases with frequency increases during the frequence of 0.2GHz-6GHz.Through experimenting, we found that the electromagnetic shielding effectiveness of the Fe-based FeSiB amorphous strip is better than that of amorphous powder. The result shown that the shielding effectiveness of single layer FeSiB amorphous strip is 40-18dB at the range of 1MHz-1.5GHz. When multi-layer FeSiB amorphous strips were applied in composites, the composites have a good wide-frequent shielding characteristics with 54-59dB at the range of 1 MHz～1.5GHz.