High temperature electromagnetic and microwave absorbing properties of polyimide/multi-walled carbon nanotubes nancomposites

Graphene Shield by SiBCN Ceramic: A Promising High-Temperature Electromagnetic Wave-Absorbing Material with Oxidation Resistance

“…For C6 with low EM wave absorption at ambient temperature, the increase in ε′, ε″, and tan δ, on the contrary, is beneficial for impedance matching because of their extremely low values (Figure S4d,f). In comparison to previous works on graphenes, as illustrated in Table , − ,− ,− either the EAB of 3.93 GHz measured at 600 °C (HT) or the RC min of −66.21 dB after oxidation at 600 °C (O) in this work is excellent. Even compared to other materials, for example, CNT–ZnO/glass and Fe 3 O 4 –MWCNTs–SiO 2 in Table , the graphene@Fe 3 O 4 /SiBCN nanocomplex also shows excellent EM wave absorption at high temperature, demonstrating immense potential as advanced EM absorption materials in harsh environments.…”

Temperature dependence of the electromagnetic and microwave absorption properties of polyimide/Ti3SiC2 composites in the X band

“…It is observed that both 3 0 and 3 00 show a remarkable temperature dependent effect at all the measured frequencies with rising temperature. Based on the Debye theory, 25,26 the increase of 3 0 can be attributed to the shorter relaxation time caused by the relaxation polarization at elevated temperature, while the increase of 3 00 is ascribed to the enhanced electrical conductivity of Ti 3 SiC 2 with rising temperature. For the composites at elevated temperature, 3 0 and 3 00 can be expressed as the following equations:…”

High temperature microwave absorbing materials

“…Therefore, some of the excited electrons jump over the surface barriers to produce current via the long-distance transfer, which causes the enhancement of the electrical conductivity of materials at high temperature. 40 On the other hand, the polarization loss consists of interfacial and dipole polarizations in the microwave frequency band. The rotation of dipoles will increase the orientation degree and decrease the internal friction at high temperature.…”