Electromagnetic-wave absorption property of Cr₂O₃–TiO₂ coating with frequency selective surface

Cr₂O₃–TiO₂ (CrTiO) composite powders were synthesized via high temperature solid-state reaction method. CrTiO coating with different Cr₂O₃ content were prepared from plasma spraying using CrTiO composite powders as spraying feed respectively. X ray diffraction analysis (XRD) and scanning electron microscopy (SEM) analysis were taken to characterize the phase components and microstructure, respectively. Electromagnetic parameters (including complex permittivity and complex permeability) of CrTiO coating were characterized and studied through a network vector analyzer. Electromagnetic-wave absorption property of CrTiO coating with different coating thickness were also examined. Results of XRD show that the main composition of the CrTiO composites are TiO₂ and Cr_0.12Ti_0.78O_1.34. Complex permittivity and complex permeability of coating increase with the increase of Cr₂O₃ content, which is ascribed that the enhancement of carrier concentration, relaxation polarization, electron polarization and magnetic polarization etc. Reflectivity results show that the composite coating displays electromagnetic attenuation at 8.2 GHz–12.4 GHz (generally called the X-band) for 15% Cr₂O₃ content coating with a sample thickness 1.9 mm. The peak value of the reflection loss reaches −10dB can be achieved at 8.2 GHz–10.2 GHz. Moreover, a frequency selective surface (FSS) coupled by a circular element and four square elements is used to further enhanced the microwave absorption performance of coating. The results show that the microwave absorption performance of the absorbing coating mainly depend on the frequency selective surface, Cr₂O₃ content and thickness of the CrTiO coating. These results imply that CrTiO coating have a potential as microwave absorbing materials for electromagnetism applications.