Conventional sintering of baryum hexaferrite Co2Z leads to a mixture of phases with a low density. In this paper we try to obtain a pure densified CO2Z hexaferrite by microwave heating. The design of the applicator is computed from both the electromagnetic physical characteristics, the dimensions and the shape of the hexaferrite sample. The travelling microwave mode is preferred to the resonant one. Microwave process consists in a debinding step followed by the high temperature sintering cycle. Sintering temperature evaluated by infrared sensors seems to be over-valued. A skin effect is observed which can be attributed to electronic conductivity due to high temperature formation of Fe2+ ions.