Abstract: After surface metallized modification, fly ash cenospheres which have the properties of light, hollow, low density, fine granularity, high intensity, heat-resistant and good conductivity are widely used as the fillings in composite materials and may probably become a new type of microwave absorber to replace the ultrafine metallic and ferrite powders. In this paper, conductive and magnetic cenospheres were fabricated by electroless plating Ni-Co-P alloy films on the surface of fly ash cenospheres after the pretreatment of sensitization and activation by SnCl2 and PdCl2. XRD, EDS, SEM and metallic microgragh analytical methods were utilized to characterize the properties and microstructure of the cenospheres coated with Ni-Co-P films by electroless plating. The results indicate that uniform and high quality Ni-Co-P alloy film with 2～4 μm thickness could be obtained after the activation by PdCl2.

Key words: Fly ash cenospheres, Electroless plating, Ni-Co-P alloy, Pretreatment, Coating