Lightweight Microwave Absorber from Industrial Waste Fly Ash Cenosphere
The present investigation demonstrates the microwave absorption property of magnetic alloy nanoparticle-coated solid industrial waste fly ash cenosphere (FAC). Here, cobalt iron (CoFe) alloy nanoparticles were chemically coated over FAC, and a composite matrix was made from these particles using epoxy resin. Surface morphology of both CoFe-FAC and epoxy/CoFe-FAC composites was studied. The dielectric loss and reflection loss (RL) of this polymer composite were studied by rectangular waveguide transmission line method. A 10 wt% CoFe-FAC-loaded epoxy composite shows an excellent microwave absorption property in the X-band (8.2–12.4 GHz). The most effective RL value −29 dB was obtained for epoxy/CoFe-FAC composite, whereas a pristine epoxy/FAC composite combination exhibits −12 dB RL under same condition. The thickness dependency of RL was also studied, and it indicates that the standard −10 dB RL can be obtained for epoxy/CoFe-FAC composite at a minimum thickness of 2 mm. The enhancement of dielectric loss, EM attenuation constant and loss factor with frequency was found to be responsible for the obtained RL.
KeywordsFly ash cenosphere (FAC) Polymer composite Reflection loss (RL) Dielectric loss Loss factor
Authors gratefully acknowledge the Department of Science and Technology (SB/S3/ME/51/2012) for financial support. This work is technically supported by IISc advanced characterization centre and CeNSE.
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