Abstract

The extensive development of diverse electronic/electrical systems has led to increased exposure to electromagnetic field and can result in many adverse effects on humans, other living beings, safety operation of various equipment, etc. Electromagnetic interference (EMI) shielding materials are in greater demand to suppress this electromagnetic pollution. The present study investigates the factors affecting the shielding efficiency of carbon black-based nanocomposite shields. Fe3O4/carbon black nanocomposite (CBN) with paraffin wax were fabricated by melt mixing methods in different weight percentages of the dispersants. The EMI shielding properties of the nanocomposites were measured using a vector network analyzer in the frequency range of 8.2 to 12.5 GHz (X band) based on the transfer/reflection method. The total shielding efficiency was used to assess the shield's protection performance. Based on the weight percentages of nanocomposite constituents, four samples were obtained. The highest average of total shielding efficiency in equal thickness belonged to the sample with 50 CBN and 15 Fe3O4 nanoparticles in weight. At different thicknesses, the highest average total shielding efficiency was related to the minimum thickness of 0.8 mm. Also, in with increasing the frequency decreased the mean total shielding efficiency in the samples. Depending on the type and weight percentage of nanocomposite compounds, one of the absorption or reflection mechanisms can be the main mechanism in reducing or eliminating electromagnetic waves in nanocomposite shields. The shield thickness and frequency of electromagnetic waves affect the protective performance of the shield. © 2022, The Korean Institute of Electrical and Electronic Material Engineers.