The fabrication of ferromagnetic metal coated conductive carbon black, their physical properties and performances in EMI shielding composites and in magnetoelastical rubber are presented. The Nickel coated carbon black has been used in a polypropylene compound and presents an increase of the electromagnetic attenuation reported to that of pure carbon/polymer composite. On the other hand, there is an evidence for the change of the elastic modulus of the rubber charged with Ni or Fe coated carbon in the presence of the magnetic field.