Electromagnetic interference shielding and microwave absorption performance of magnetic Co@C/Na2SiO3 composite at 673 K

Abstract A high temperature microwave absorber with magnetic metal as an additive (Planar anisotropy Co@C/Na2SiO3 composite) was successfully fabricated. Following a C-coat treatment and complex formation with Na2SiO3, the composite worked stably at 673 K and showed outstanding high temperature stability. Evaluation of TG analysis results and static magnetic properties before and after sintering adequately illustrated that its antioxidant performance was outstanding. Its electromagnetic interference (EMI) shielding may reach 20 dB with a thickness of 10 mm, where absorption inside the composite was the main mechanism underlying attenuation. A reflection loss (RL) intensity below -8 dB may be obtained in the X band with a thickness of 1.7 mm at 673 K. The absorption strength of the composite was lower than -10 dB in the range of 8.7–11.8 GHz. Moreover, the composite showed excellent stability at high temperatures. Compared with dielectric loss absorbers, magnetic metallic absorbers have an obvious advantage in both absorption performance and price, and show irreplaceable potential for extensive use and commercialization in the field of high temperature absorbance.