Preparation and the electromagnetic interference shielding in the X-band of carbon foams with Ni-Zn ferrite additive

The composite of carbon foam with Ni-Zn ferrite as additive has been developed via foaming and carbonization process for electromagnetic interference shielding, using coal tar pitch as precursor and Ni-Zn ferrite as an additive. It was observed that the shielding effectiveness (SE) over the X-band frequency is enhanced along with the increase of Ni-Zn ferrite additive amount. The carbon foam with 15 wt% Ni-Zn ferrite shows a SE of 42 dB, which has a promising application prospect. The electromagnetic interference shielding mechanism of carbon foam with different amount of Ni-Zn ferrite additive is discussed in the work. An absorption-dominant mechanism, which is mainly associated with the magnetic property determined by the amount of Ni-Zn ferrite additive, has been revealed. It is also found that the mechanical strength of resultant carbon foams increases firstly and then decreases with the continuously increased amount of Ni-Zn ferrite additive.