Abstract: Microwave reflectivity of epoxy matrix composite containing Mn-Zn ferrite sintered at different temperatures such as 1100℃ , 1200℃ , 1300℃ , 1400℃ and 1500℃ is measured in the frequency range of 11.0GHz to 18.0 GHz. The phase constitution of the Mn-Zn ferrite is analyzed by X-ray diffraction. It is found that Mn-Zn ferrites sintered at different temperatures have the same main phases, while the relative content of the same kind is different. The higher the sintering temperature is, the more content Fe3O4has, and the less centent α-Fe2O3and γ-Fe2O3have. The results also show that the ferrite prepared at 1500℃ has better microwave absorbing property than those prepared at other temperatures. It may be concluded that the variation of Sintering temperature results in the change of hysteresis loss and dielectric loss of Mn-Zn ferrite. The electron exchange effect between Fe2+and Fe3+ becomes stronger and, the turbulent loss is more remarkable due to the formation of excessive Fe2+in deoxidizing of Fe2O3at higher sintering temperature.

Key words: Mn-Zn ferrite, sintering temperature, microwave absorbing behaviour, phase consti-tution