Controllable synthesis of defective carbon nanotubes/Sc2Si2O7 ceramic with adjustable dielectric properties for broadband high-performance microwave absorption

Dielectric response and electromagnetic wave absorption of novel macroporous short carbon fibers/mullite composites

“…Consequently, high‐performance EM wave absorbing materials which have drawn increasing attention are now regarded as an effective strategy to eliminate the EM pollution. Carbon‐based composites, 5‐9 metal‐based composites, 10‐14 polymer‐based composites, 15‐19 and ceramic‐based composites, 20‐24 have been extensively studied for EM wave absorption application. However, applications of carbon, metal, and polymer‐based composites are limited at elevated temperatures due to their degraded strength and EM wave absorption under oxidizing and/or corrosive atmosphere 25 .…”

Preparation and characterization of CNT films/silicone rubber composite with improved microwave absorption performance

“…Figure 9 presents the changes of Z in the three CNT/SR composites absorbers. Ideally, the condition is = Z 1 for absolutely entering the interior of absorber [10,47,48]. The Z values of 0.5 CNT films/SR are very closely the ideal value of 1 in the range of 14.54-16.93 GHz, revealing the greatly enhanced impedance matching in this frequency range.…”

“…Multiple Cole-Cole semicircles are easily found in the inset of figure 11(c), showing multiple Debye dipolar relaxations for the contribution of permittivity dispersion in 0.5 CNT films/Sr Meanwhile, those of CNT powders/SR absorbers present worm-like short plots of e¢ versus e near the origin of coordinates, showing inferior effects on permittivity dispersion with less Cole-Cole polarization relaxation processes. Another useful tool is denoted as attenuation constant (α) to evaluate the internal microwave attenuation of absorber, being described as the following equation:[48,56]…”

Tuning Dielectric Loss of SiO2@CNTs for Electromagnetic Wave Absorption

“…Their intensity ratios (ID/IG) for the SiO2@Fe3C/Fe@NCNT-GT was 1.002, which indicated rich defects in the sample. These defects in the SiO2@Fe3C/Fe@NCNT-GT can greatly improve the polarization relaxation and contribute to enhancing the absorption of electromagnetic waves [21]. As shown in Figure 2c, the N2-sorption isotherms of the SiO2@Fe3C/Fe@NCNT-GT displays type-IV loops, revealing that the mesopores existed in the prepared sample.…”