Design of light weight multi-layered coating of zinc oxide-iron-graphite nano-composites for ultra-wide Bandwidth microwave absorption

The present study focused on the formulation of suitable material combination for good microwave absorption with ultra-wide Bandwidth at minimum coating thickness. For this purpose, a unique materials combination of semiconductor, conductor and magnetic materials has been specifically designed through a simple fabrication method to meet the necessity of enhanced absorption characteristics in the frequency range of 4.0-12.0 GHz. The chosen bulk materials like zinc oxide (ZnO), iron (Fe), and graphite (C) have been subjected to high energy ball planetary mill for fabricating the nano-composites. The impact of milling time on microwave absorption behavior of zinc oxide-iron-graphite nano-composites has been studied. The maximum microwave absorption value of -17.40 dB has been obtained for 15 h milled sample with average grain size of similar to 10.0 nm for single-layer absorber of coating thickness 3.0 mm with broad Bandwidth of 6.43 GHz (4.0-10.43 GHz). The double-layer absorber has been optimized by multi-layering technique to increase the microwave absorption for less coating thickness. This type of material may be quite useful for radar cross section reduction at C and X-band.