Abstract:

Ferrite-encapsulated cenosphere powders were prepared by citrate sol-gel method. The additive was used to improve the performance of ferrite coating. Microstructure of the products was tested by SEM and EDS. It was found that the coating was independent of the type of ferrite. Adding glycol or polyethylene glycol into the precursors can help the ferrite encapsulation. Microwave reflection loss of the coatings with thickness of 1.8mm made from ferrite-encapsulated cenosphere powders was tested in the frequency range from 5GHz to 18GHz. It was found that the ferrite-encapsulated cenosphere coating exhibited better microwave absorbing property than the pure ferrite. More, adding glycol can improve the microwave absorbing property of the coatings.

Key words: ferrite, cenospheres, microwave absorption, glycol, polyethylene glycol