Preparation and wave attenuation properties of GR/Fe93.5Si3.5Gd3 composite powders

Abstract

In this paper, different graphene (GR)/Fe93.5Si3.5Gd3 composite powders were prepared via high-energy ball milling. Through the analysis of the structural morphology and electromagnetic parameters of the composite powder, the effects of ball milling time and graphene on the wave absorption properties of the composite powder were investigated. It is shown that in the ball-milled composite powder, graphene is compounded with the alloy powder in an amorphous state, and the particle size of the composite powder decreases with the increase of ball milling time. Moreover, the addition of graphene and the introduction of high-energy ball milling did improve the electromagnetic parameters of the composite powder. With other conditions guaranteed to be the same, the real part of dielectric constant of the composite powder rises by up to 472.94% and the real part of permeability increases by up to 23.80%. The optimized change of electromagnetic parameters increases the conduction loss of the composite powder, together with the combined effect of spatial polarization and orientation polarization, it increases the dielectric loss of the composite powder. The magnetic loss of the composite powder is also greatly improved by the change of the main mode of magnetic loss to natural resonance. The increase in dielectric loss and magnetic loss has greatly improved the electromagnetic wave absorption performance of the composite powder. Among them, at 0.3 ∼ 8.5 GHz, the electromagnetic loss of 1.0 wt% GR/Fe93.5Si3.5Gd3 ball milled for 24 h reaches 1.20 ∼ 11.78. With other conditions being the same, it is respectively 718.06% and 708.22% higher than the composite powder without graphene and the composite powder with the shortest ball milling time, showing excellent microwave attenuating performance.