Flexible Electromagnetic Shielding Nano-Composites Based on Silicon and NiFe2O4 Powders

Abstract

In this paper, the obtaining and characterization of five experimental models of novel polymer composite materials with ferrite nano-powder are presented. The composites were obtained by mechanically mixing two components and pressing the obtained mixture on a hot plate press. The ferrite powders were obtained by an innovative economic co-precipitation route. The characterization of these composites consisted of physical and thermal properties: hydrostatic density, scanning electron microscopy (SEM), and TG DSC thermal analyses, along with functional electromagnetic tests in order to demonstrate the functionality of these materials as electromagnetic shields (magnetic permeability, dielectric characteristics, and shielding effectiveness). The purpose of this work was to obtain a flexible composite material, applicable to any type of architecture for the electrical and automotive industry, necessary for protection against electromagnetic interference. The results demonstrated the efficiency of such materials at lower frequencies, but also in the microwave domain, with higher thermal stability and lifetime.

Sustainable Geopolymer Structural Insulation Panels Obtained with the Addition of Power Plant Ash and Furnace Slag with Potential Uses in the Fabrication of Specialized Structures

“…Finally, some studies (e.g., [42,43]) emphasized the electromagnetic properties of geopolymer composites, mainly related to the GHz domain, but the recipes for these materials included either iron powder/iron ore fine or carbon powder/fibers, materials known to enhance the electromagnetic shielding properties by themselves, so the geopolymer recipe in fact makes no contribution. It must be mentioned that such compositions are far from normal for geopolymer materials, made with high costs, and address a disputable market, related mainly to electronic applications, in which other types of composites are more suitable for use (see, for example, [44][45][46][47]).…”