Enhanced microwave absorption of plasma-sprayed Ti₃SiC₂/glass composite coatings

The Ti₃SiC₂/glass composite coatings were prepared by atmospheric plasma spraying. There are no evident microcracks between Ti₃SiC₂ and glass matrix due to low residual stress resulting from the matching CTE of them. The XRD patterns of the as-sprayed Ti₃SiC₂/glass composite coatings are composed of glass matrix, Ti₃SiC₂, TiC, and a small amount of Ti₅Si₃. The short dwell time and quite low oxygen partial pressure in plasma jet flow restrain TiC and Ti₅Si₃ from further oxidation. Both the real and imaginary part of the complex permittivity increase with rising Ti₃SiC₂ content. The coating with 25 wt% Ti₃SiC₂ possesses excellent microwave absorption properties. The minimum reflection loss is −47.7 dB (> 99.99 % absorption) at 10.6 GHz with a thickness of 1.4 mm and the bandwidth (<−5 dB) can be obtained in the frequency range of 8.2–12.4 GHz. The impedance matching and dielectric loss of the coating result in the microwave absorption properties improved. The enhanced microwave absorption performance suggests that the Ti₃SiC₂/glass coating could be a good candidate for highly efficient microwave absorption material.