Electromagnetic parameters of ultra-fine SiC, SiC whisker and nanometer SiC were tested to evaluate the microwave absorbing properties. Optimized nanometer SiC-CNTs/AT13 composite was fabricated by high energy mechanical commixture. Nanometer SiC-CNTs/AT13 absorbing coating was prepared by multi-functional micro-plasma spray system. Morphology and the structure of the powders were characterized by scanning electron microscope. The microwave absorbing characteristic of the coating was evaluated by measuring the reflection loss using an HP8757E scalar quantity network analyzer in the 2-18 GHz band range. The coatings were density, low porosity and uniform morphology. The reflection loss values of -10 dB are obtained in the 2~18GHz range. The minimum reflection loss of the coating is -13.12 dB at 12.64 GHz, and the bandwidth of the reflectivity below -5dB is 9.36GHz. It is indicated that the plasma spraying process is an effective way of preparing microwave absorbing coating.
