A Mössbauer investigation of nano-NiFe alloy/expanded graphite for electromagnetic shielding

A new material is prepared by impregnating the expanded graphite (EG) into ethanol solutions of metal acetate and then drying and reducing it in H2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_2$$\end{document}. It contains the EG and the nanoparticles of the magnetic Ni–Fe alloy for the electromagnetic shielding. Its morphology, phase structure, magnetic properties, and electromagnetic shielding effectiveness (SE) are investigated in our experiment. It shows that the morphology, the phase structure, and the magnetic property of the composite can be modified by altering the Ni content in the alloy nanoparticles. Interestingly, the SE can be enhanced to 54–70 dB at low frequencies (300 kHz–10 MHz) by dispersing the magnetic nanoparticles onto EG.