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

Gan Jet Hong Melvin,Qing‐Qing Ni,Zhipeng Wang

doi:10.1002/gch2.201900045

Gan Jet Hong Melvin, Qing‐Qing Ni + Show 1 more

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https://doi.org/10.1002/gch2.201900045

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Abstract

Agricultural wastes such as rice husks (RHs) are valuable due to their feasibility to be converted into carbon materials, low cost, and abundancy in contrast to the conventional carbon material sources. In this study, RHs are carbonized at various temperatures from low to high temperatures, and their electromagnetic (EM) wave absorption properties are evaluated. Carbon materials, silicon carbide (SiC) whiskers, and SiC particles are obtained from RHs carbonized at 1500 °C (CRH1500) for 0.5 h with presence of Ar gas at 1 atm. In order to evaluate their EM wave absorption performance, complex permittivity and permeability are measured by using vector network analyzer, and the values are utilized in the reflection loss (R.L.) calculation according to the transmission line theory. CRH1500, 40 wt% with thickness of 1.6 mm exhibits minimum R.L. of ≈−55.4 dB (>99.9997% absorption) at 11.37 GHz and response bandwidth (R.L. < 10 dB, > 90% absorption) of 4.21 GHz. Low‐cost and abundant RHs, carbonized at various temperatures, show significant absorption performance. Their absorption performance and response bandwidth are highly dependent on matching thickness, indicating that they can be easily modulated for promising electromagnetic wave absorber materials.

Highlights

Agricultural wastes such as rice husks (RHs) are valuable due to their this might leads to device malfunction, disturbance of electronic system, harm feasibility to be converted into carbon materials, low cost, and abundancy the environment, or affect the health of in contrast to the conventional carbon material sources
The disclosure of unnecessary or excessive electromagnetic knowledge, the EM wave absorption performance of rice husk (EM) wave emission are expected due to the extensive utiliza- (RH) carbonized at high temperatures which produced hettion of devices/applications associated with EM wave especially erogeneous materials including carbon materials and ceramic at GHz frequency ranges (G, X, Ku-band, etc.) in electronic materials has not been fields, wireless communication, and radar.[1–5]
Low cost and abundantly available RHs are carbonized at various temperatures, which produced a mixture of carbon and ceramic materials

Summary

Introduction

Agricultural wastes such as rice husks (RHs) are valuable due to their this might leads to device malfunction, disturbance of electronic system, harm feasibility to be converted into carbon materials, low cost, and abundancy the environment, or affect the health of in contrast to the conventional carbon material sources.

Results

Conclusion