Facile preparation and high microwave absorption of C/SiO2 composites with an ordered inter-filled string mesostructure

A kind of ordered inter-filled mesostructural C/SiO2 composites has been prepared by a combined processing of nanocasting method with hot-pressing sintering. In the composites, carbon particles can be incorporated, in the form of ordered nanowire arrays, into channels of mesoporous silica templates and endow the sintered composite with high electrical conductivity up to 1.47 x 10(3) S/m. The electromagnetic interference (EMI) shielding efficiency (SE) of the C/SiO2 composite, with a thickness of 2.0 mm, is as high as 35 dB and dominated by microwave absorption in the X band (8.0-12.0 GHz). The high complex permittivity of sample indicates that the large dielectric loss results in a significant effect on the microwave attenuation. Therefore, such conductive C/SiO2 composite ceramics with an inter-filled mesostructure will provide us with new applications as microwave absorbing materials. (C) 2012 Elsevier B.V. All rights reserved.