A study on the electromagnetic properties of graphite/bismuth/bismuth oxide-coated composites

Abstract

Coating is a commonly used process for the preparation of protective textiles. In this study, the absorbing coated composite material was prepared by a coating process, using plain weave polyester/cotton fabric as the base fabric, PU-2540 polyurethane as the binder, and graphite, bismuth and bismuth oxide as the functional particles. The effects of the content of functional particles and the ratio of functional particles on the dielectric constant, reflection loss, shielding effectiveness, and tensile strength of the single-layer coating composites were studied using the control variable method. The results showed that when the frequency was 1–1000 MHz, the real and imaginary parts of the dielectric constant, the tangential value of the loss angle, and the tensile value increased with the increase of the coating content, and the polarization, loss and attenuation property, and mechanical property of the electromagnetic wave were enhanced. When graphite, bismuth, and bismuth oxide was mixed at the ratio of 9:0:0 in weight, the polarization property was the best. When mixed at the ratio of 6:1:2 in weight, the loss performance and attenuation ability were the best. When mixed at the ratio of 6:3:0 in weight, the absorbing property and mechanical property were the best. When mixed at the ratio of 6:2:1 in weight, the shielding property was the best.

Preparation and characterization of an electromagnetic composite polypyrrole/polyethylene short filament geotextile

“…Generally, when the RL value of the material is not greater than –10 dB, it can be considered that 90% of the electromagnetic waves are lost. 30…”

“…Generally, when the RL value of the material is not greater than -10 dB, it can be considered that 90% of the electromagnetic waves are lost. 30 SE is an important indicator of the shielding performance, and samples were tested with reference to the standard GJB 6190-2008 standard, "Measurement method of the shielding effectiveness for electromagnetic shielding materials." Generally, when the SE of the material is greater than 20 dB, it can be considered that 90% of the electromagnetic waves are shielded.…”

Recent research progress of carbon-based and their composites for electromagnetic waves absorption

“…That is, the frequency width of RL <−10 dB represents the frequency range of EMW that can absorb 90% of the energy. 30,31 Generally speaking, the wider the effective absorption width, the better the absorbing performance of the materials. When evaluating the absorbing performance of the materials, the vector network analyzer is used to test the magnetic and dielectric spectra, and then the reflection loss is calculated according to the transmission line theoretical formula.…”

Effect of bismuth oxide nanoparticle on the electromagnetic interference shielding and thermal stability of industrial waste based-geopolymer composites

“…Several research has incorporated various conductive fillings and loading to cement-based, such as carbon nanotubes with controllable silica shells 9 , graphene-coated CNT’s 10 , 11 , nickel fiber 12 , stainless-steel furnace dust 13 and metallic nanoparticles such as cobalt, nickel, and iron oxide 14 . One potential metallic nanoparticle that could be used as a conductive admixture is Bismuth Oxide (Bi 2 O 3 ), due to its good absorbing properties 15 . When Bi 2 O 3 is added as a filler or dopant, the uniformity and density of the material will improve and, consequently, its crystallinity.…”