Tuning microwave permittivity coefficients for enhancing electromagnetic wave absorption properties of FeCo alloy particles by means of sodium stearate surfactant

Abstract

FeCo is well known as one of the most important Fe base alloys due to its unique properties. In this research FeCo were prepared by a wet chemical reduction method. Sodium stearate (SS) surfactant was used in different amounts as a modifier. XRD and FE-SEM were used to study phase and morphology characteristics of the products. Paraffin matrix composite samples containing 80%wt FeCo were prepared to measure the frequency dependence of the permeability and the permittivity utilizing Vector Network Analyzer (VNA). The results showed that by an increase in SS amounts, the permittivity was decreased. Reflection loss (RL) plots in the frequency range of 1–18 GHz demonstrated that the most wideband RL plots were for the sample with 0.004 mol SS because of its good impedance matching characteristics. For this sample, the RL bandwidth (−10 dB) by a thickness of 2.7 mm occurred 2.2 GHz in C band. Also, it covered the whole range of X and Ku bands having thicknesses of 1.5 mm and 1.1 mm, respectively. The maximum RL of −44 dB was obtained in the frequency of 5 GHz. The results of the research indicate that the composites containing FeCo particles are suitable candidates applicable as thin and wideband microwave absorbers.