Study on the electromagnetic properties of Ni-Zn ferrite powders and the effect of their powder-size distributions on microwave absorbing composites based on graphene/Epoxy

Abstract

This research presents the effects of the size distributions of Ni-Zn ferrite powders as well as addition of graphene on the absorbing properties of electromagnetic wave of epoxy/Ni-Zn ferrite/Graphene composite material Ni0 5Zn0 5Fe2O4 powder was prepared by using conventional solid-state method calcined at 1100℃for 2 hours Three distinct size-distributions of Ni-Zn ferrite powers were isolated through contrived sieving-method and extra ball milling The experimental measurements and theoretical analysis showed that there are two wave-absorbing mechanisms for the epoxy/Ni-Zn ferrite composite material magnetic loss for low-frequency absorption of 2-6 GHz and dielectric loss for high-frequency absorption of 16-18 GHz The absorbing efficiency of the composite materials increases with the size and volume fraction of Ni-Zn ferrite powers in the absorbing materials For the object of reflection loss less than -10 dB centered at 5 GHz 18 5 vol% of Ni0 5Zn0 5Fe2O4 with distribution of large power mixed with epoxy is recommended for which the thickness of the composite material is expected less than 7 mm For the study of effect of graphene on the absorbing properties the present experiment demonstrated that reflection loss of -10 dB centered at 5 GHz and smaller thickness of composite material was possible for the addition of 3 25 vol% of graphene

Date of Award	2020
Original language	English
Supervisor	Bing-Jing Li (Supervisor)