Synthesis and microwave absorbing properties of FeNi alloy incorporated ordered mesoporous carbon–silica nanocomposite

Ordered mesoporous carbon–silica/FeNi nanocomposite were prepared by a sol–gel method and following sintering process. The electromagnetic parameters were measured in the 0.5–18 GHz range. Compared with ordered mesoporous carbon–silica composite, the permittivity of ordered mesoporous carbon–silica/FeNi nanocomposite decreases, while the permeability almost remains unchanged. The optimal reflection loss of ordered mesoporous carbon–silica/FeNi nanocomposite can reach −45.6 dB at 11.1 GHz for a layer thickness of 3.0 mm. The enhanced microwave absorption of the mesoporous carbon–silica/FeNi nanocomposite is due to better balance between the complex permittivity and permeability, geometrical effect, as well as multiple reflections by the ordered mesoporous structure.

Frequency dependence of reflection loss for CS (a) and CS–FeNi (b); the dependence of λ/4 thickness on frequency for CS (c) and CS–FeNi (d).Figure optionsDownload as PowerPoint slideHighlights
► FeNi alloy was incorporated into ordered mesoporous carbon-silica nanocomposite.
► Greater than 90% absorption was obtained with various thicknesses.
► Maximum reflection loss of −45.6 dB at 11.1 GHz for a layer of thickness 3.0 mm was obtained.