Effect of Porous Structure on the Microwave Absorption Capacity of Soft Magnetic Connecting Network Ni/Al2O3/Ni Film

Abstract

Microwave radar absorbing materials have been the focus of the radar stealth research field. In this study, ceramic structured porous honeycomb-like Al2O3 film was prepared by anodic oxidation, and an Ni layer was deposited on the Al2O3 film via electrodeposition in a neutral environment to form a flower- and grain-like structure in a three-dimensional (3D) network Ni/Al2O3/Ni film. The films both have a through-hole internal structure, soft magnetic properties, and absorb microwaves. The dielectric loss values of two films were little changed, and the maximum microwave absorption values of flower- and grain-like Ni/Al2O3/Ni film were −45.3 and −31.05 dB with relatively wide effective bandwidths, respectively. The porous ceramic structure Al2O3 interlayer prevented the reunion of Ni and isolated the eddy current to improve the microwave absorption properties. The material presented in our paper has good microwave absorption performance with a thin thickness, which indicates the potential for lightweight and efficient microwave absorption applications.

Comprehensive study of lumped kinetic models and bio-oil characterization in microwave-assisted pyrolysis of Sargassum sp.

“…Particularly for microwaves emitted from standard microwave ovens at a frequency of 2.45 GHz, the small pore size of CAC notably diminishes its microwave absorption efficiency. 41,42 It is recognized that microwave absorbers with mesoporous pores, ranging from 2 to 50 nm, are more aptly suited for the absorption of low-frequency microwaves. 43…”

A review of recent advancements in Ni-related materials used for microwave absorption

“…To date, many metal oxides/sulfides, such as NiO, MnO 2 , TiO 2 , ZnO, Al 2 O 3 , Fe 3 O 4 , MoS 2 , and Ni 3 S 2 , have been employed in combination with Ni and Ni-containing alloys, and all the resultant composites have exhibited significant superiority in microwave absorption [90,[94][95][96][97][98][99][100][101][102][103][104][105][106]. For example, Wang et al obtained core-shell Ni@Ni 2 O 3 particles through the in situ oxidation of Ni particles in the presence of hydrogen peroxide, and they confirmed that the thin Ni 2 O 3 shell greatly improved the impedance matching of Ni@Ni 2 O 3 particles, but affected their relative complex permeability less [107].…”

Microstructures, Mechanical Properties and Electromagnetic Wave Absorption Performance of Porous SiC Ceramics by Direct Foaming Combined with Direct-Ink-Writing-Based 3D Printing

“…Nowadays, various mainstream methods have been widely investigated with the fabrication of porous ceramics and composites: partial sintering, replica template, sacrificial template, and direct foaming [ 21 , 22 , 23 , 24 ]. However, the challenges to these methods, including the complex manufacturing processes and high sintering temperatures, as well as the simple methods to shape porous SiC ceramics into complex shapes, remain unexplored [ 25 ].…”