Structure and microwave absorption properties of Nd–Co–Ni alloys

Abstract

To study the effect of Ni content on microwave absorption of Nd 2 Co 17 alloy. The Nd 2 Co 17-x Ni x (X = 0.0, 0.2, 0.6, 1.0, 1.4) powders were prepared by arc smelting and high energy ball milling method. The structure and morphology of the powder were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electromagnetic parameters of the powder were measured by vector network analyzer (VNA) at room temperature. The XRD results indicate that the prepared powder maintain the Nd 2 Co 17 phase. The minimum reflectivity value frequency shifts towards the lower frequency with the increase of Ni content. The minimum reflectivity value of Nd 2 Co 15.6 Ni 1.4 alloy reaches about -26.6 dB at 2.9 GHz with the matching thickness of 2.2 mm. And the milled powder was tempered ranging of 50-200°C for 1 h. The minimum reflectivity frequency shifts to higher frequency region compared to the powder without heat treatment. The absorbing frequency bandwidth increases with the tempering treatment increase.

Challenges and future perspectives on microwave absorption based on two-dimensional materials and structures

“…New types of carbon-based materials include graphene (graphene oxides), single-wall and multiple-wall carbon nanotubes, graphite and carbon black. However, the absorbing mechanism of carbon materials originates only from dielectric loss and electrical loss, which typically prevent strong absorption and effective multiband absorption [24,[65][66][67][68][69][70][71][72][73]. The most important factors such as the intensity of multiplescattering and interface polarization loss are closely related to the microstructures of the absorbers.…”