A comparative study on the dielectric response and microwave absorption performance of FeNi-capped carbon nanotubes and FeNi-cored carbon nanoparticles

Daitao Kuang; Shiliang Wang; Lizhen Hou; Heng Luo; Lianwen Deng; Chuansheng Chen; Min Song; James L Mead; Han Huang

doi:10.1088/1361-6528/abc644

A comparative study on the dielectric response and microwave absorption performance of FeNi-capped carbon nanotubes and FeNi-cored carbon nanoparticles

Nanotechnology. 2020 Dec 10;32(10). doi: 10.1088/1361-6528/abc644.

Authors

Daitao Kuang^{1

2}, Shiliang Wang¹, Lizhen Hou³, Heng Luo^{1

2}, Lianwen Deng¹, Chuansheng Chen⁴, Min Song², James L Mead⁵, Han Huang⁵

Affiliations

¹ School of Physics and Electronics, Central South University, Changsha, 410083, People's Republic of China.
² State Key Laboratory for Powder Metallurgy, Central South University, Changsha, 410083, People's Republic of China.
³ School of Physics and Electronics, Hunan Normal University, Changsha, 410081, People's Republic of China.
⁴ College of Materials Science and Engineering, Changsha University of Science and Technology, Changsha, 410114, People's Republic of China.
⁵ School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.

PMID: 33126231
DOI: 10.1088/1361-6528/abc644

Abstract

The mechanisms responsible for the dielectric response of C-based microwave absorbers remain a long-standing theoretical question. Uncovering these mechanisms is critical to enhance their microwave absorption performance. To determine how different C forms alter the dielectric response of C-based absorbers, FeNi-capped carbon nanotubes (FeNi-CNTs) and FeNi-cored carbon nanoparticles (FeNi-CNPs) are synthesized, and a comparative study of their dielectric responses is then carried out in this study. The as-synthesized FeNi-CNTs and FeNi-CNPs have similar magnetic properties and complex permeabilities, but differ in complex permittivities. It is shown that FeNi-CNTs have a much stronger dielectric loss than FeNi-CNPs. At a thickness of 2.8 mm, a low optimal reflection loss of -32.2 dB and a broad effective absorption bandwidth of 8.0 GHz are achieved for FeNi-CNTs. Meanwhile, equivalent circuit models reveal that the CNT network of the FeNi-CNTs could introduce an electrical inductance that can effectively improve its dielectric loss capability. This study demonstrates that designing a composite with a tailored C form and composition is a successful strategy for tuning its microwave absorption performance. Furthermore, the equivalent circuit modeling is an effective tool for analyzing the dielectric response of the microwave absorbers, as is expected to be applicable for other metal-C composites.

Keywords: CNT; FeNi; core–shell nanoparticle; dielectric response; microwave absorption.