Performance of barium titanate@carbon nanotube nanocomposite as an electromagnetic wave absorber

Abstract

Barium titanate (BT) nanoparticles were fabricated using sol-gel method, and then immobilized onto the surface of carbon nanotubes (CNTs) to fabricate heterogeneous barium titanate@carbon nanotube (BT@CNT) nanocomposites. The electromagnetic (EM) wave absorption ability increased as the weight fraction of BT@CNT increased.The BT@CNT 30 wt.% nanocomposites with thickness of 1.1 mm showed a minimum reflection loss (R.L.) of ∼ − 37.2 dB (> 99.98% absorption) at 13.9 GHz with a response bandwidth of 1.6 GHz (12.3 ∼ 13.9 GHz), and were the best absorber when compared to similar nanocomposites with different thicknesses. The relationship between conductivity and EM wave absorption properties was also discussed. Appropriate conductivity also plays an important role to obtain optimum absorption performance.BT@CNT nanocomposites exhibited significant absorption ability, and this indicates that they can be utilized as an effective EM wave absorber material.

Electromagnetic Wave Absorption Performance of Carbonized Rice Husk Obtained at Various Temperatures

“…As the frequency increased, the complex permittivity declined. This can be attributed to the dipoles in CRHs are not maintained in the phase orientation with the electric vector of the penetrating EM field . Comparatively, CRH1500 exhibited highest complex permittivity in contrast to other CRHs.…”

“…The disclosure of unnecessary or excessive electromagnetic (EM) wave emission are expected due to the extensive utilization of devices/applications associated with EM wave especially at GHz frequency ranges (G‐, X‐, Ku‐band, etc.) in electronic fields, wireless communication, and radar . Furthermore, this might leads to device malfunction, disturbance of electronic system, harm the environment, or affect the health of human beings, which has attracted the urgency to develop EM wave absorbing materials .…”

“…in electronic fields, wireless communication, and radar . Furthermore, this might leads to device malfunction, disturbance of electronic system, harm the environment, or affect the health of human beings, which has attracted the urgency to develop EM wave absorbing materials . Effective EM wave absorber materials will be able to dissipate EM wave energy into heat or different forms of energy and in result the EM wave cannot be reflected or permeated through the absorber materials, in addition to other advantageous properties such as lightweight, tunable absorbing ranges, and multifunctionality .…”

“…Based on the free electron theory, higher ε″ values are proportional to higher conductivity values . Thus, relatively higher electrical conductivity of CRH1500 permits strong polarization to take place, dissipation of electrostatic charges, Ohmic losses, or multiple scattering attributed to the heterogeneity and large specific area, which lead to improved complex permittivity . It is worth noticing that certain conductive materials are suitable for electromagnetic interference (EMI) shielding material, where the core process of EMI shielding is to produce a blockage made of electrically conductive materials that attenuates radiated or conducted EM energy through reflections and absorption .…”

“…For CRH1500 and CRH2200, the complex permeability slightly increased until a certain frequency, after which it started to decline. This behavior can be related to the natural resonance or eddy currents loss initiated from the graphitized carbon . Graphitized carbon in an alternating magnetic field will build up a close induced current inside the sample, which would scatter the energy and known as the eddy current loss .…”