Significantly enhanced electromagnetic interference shielding in Al2O3 ceramic composites incorporated with highly aligned non-woven carbon fibers

Macroscopic parallel aligned non-woven carbon fibers were incorporated into Al 2 O 3 composites in this study to evaluate the contribution of multiple reflections to the total electric magnetic interference (EMI) shielding. Results indicate that parallel aligned non-woven carbon fiber layers contribute significantly to the total EMI shielding effectiveness (SE T ) of Al 2 O 3 composites by largely enhancing the EMI absorption, and seven parallel aligned thin non-woven carbon fiber layers finally make the almost microwave-transparent Al 2 O 3 an excellent EMI shielding material with an EMI SE T as high as 29–32 dB in the X-band frequency range. The volume fraction of carbon fibers in Al 2 O 3 composites with seven carbon fiber layers is calculated to be only 0.5%, and therefore the EMI SE enhancement efficiency by parallel aligned large non-woven carbon fiber layers is much higher than other highly conducting nano fillers. It validates the significance of multiple reflections in achieving high EMI shielding properties in ceramic composites and provides an instructive approach to design efficient EMI shielding ceramic composites.