Defect Dipole-Induced HfO₂-Coated Ti₃C₂T_x MXene/Nickel Ferrite Nanocomposites for Enhanced Microwave Absorption

Abstract

This work reports for the first time the synthesis of a HfO 2 -coated Ti 3 C 2 T x MXene sandwich-like nanostructure (MXHf) using a simple hydrothermal method and their excellent microwave absorption property in combination with nickel ferrite and epoxy matrix. The nanocomposites of 2, 3, and 4 mm thick samples were tested for microwave absorption in the X-band, and a minimum reflection loss (RL min ) of −20.9 dB with EAB (effective absorption bandwidth) of 2.32 GHz was achieved for the 3 mm thick sample. Its superior performance results from the strong dielectric polarization of defect dipole in the MXene structure, the high number of oxygen vacancies brought about by HfO 2 nanoparticles, rich micro-interfaces in the sandwich-like HfO 2 -Ti 3 C 2 T x -HfO 2 structure, and impedance matching by NiFe 2 O 4 . A probable mechanism of absorption is proposed. Hence, HfO 2 /Ti 3 C 2 T x /NiFe 2 O 4 nanocomposites possess essential properties for real-time application in the defense and telecommunication industries.

Flexible, Stretchable, and Lightweight Hierarchical Carbon-Nanotube-Decorated Carbon Fiber Structures for Microwave Absorption

“…Figure c,d shows the comparison of the fabricated CFCNT0.35 nanocomposite with filler wt %, R L , and EAB for other available investigations. − Further, the comparison of CFCNT0.35 is made with the recently available nanocomposite in Supporting Information Table S3. The CFCNT0.35 nanocomposite structure has the ability to function in the presence of outside pressures in extreme environmental conditions despite degrading R L performance.…”

Influence of Exfoliated Boron Nitride for Fabrication of a Lightweight Wideband Microwave Absorbing Material

“…The AC had a tight relationship with dielectric and magnetic loss abilities. The AC (α) might be estimated using the results of earlier studies (eq ): , 0.25em α = 2 π f c ( μ ″ ε ″ − μ ′ ε ′ ) + false( μ ″ ε ″ prefix− μ ′ ε ′ false) 2 + false( μ ′ ε ″ prefix− μ ″ ε ′ false) 2 …”

“…The AC had a tight relationship with dielectric and magnetic loss abilities. The AC (α) might be estimated using the results of earlier studies (eq ): , …”

“…The AC had a tight relationship with dielectric and magnetic loss abilities. The AC (α) might be estimated using the results of earlier studies (eq 6): 67,68 RL measures how well microwave-absorbing materials effectively absorb microwaves. The following is a description of RL curves in terms of transmission line theory (eq 7): 67,69 (7) The following equation may be used to represent Z in , which is the absorbing material's input impedance in this case (eq 8): (8) where f is the frequency, c is the speed of an EM wave in free space, d is the thickness of the absorber, and ε r and μ r are the relative permittivity and permeability, respectively.…”