Regulation of dielectric loss by different exposed crystal facets in graphite-coated titanium carbide nanocomposites

Abstract

The mechanism of different exposed crystal surfaces on dielectric polarization characteristics is of great significance to understand the interface impedance matching. In this work, the controllable preparation of titanium carbide (TiC) with different exposed crystal surface was realized by adjusting the reaction atmosphere, which is based on the growth rate and surface energy of different exposed facets. TiC(100)/graphite and TiC(111)/graphite interfaces are found in the truncated octahedral TiC/C nancomposites, while only TiC(100)/graphite interface exits in the cubic nanocomposites. Experimental conclusion companied by theoretical calculations identify that dielectric loss capacity is improved by the strong localization of polarized charge at TiC(111)/graphite interface. Due to the enhanced permittivity, dielectric loss ability and absorption coefficient, the truncated octahedral TiC@C nanocomposites exhibit the reflection loss of −45.1 dB and the effective frequency bandwidth of 5.3 GHz at 2.1 mm. The proposed interfacial modulation strategy can provide a reference for designing high efficiency microwave absorber.