Abstract: The Fe_100-xCr_x(x=3,5,7,9,11) alloy powders were prepared by using the means of mechanical alloying,and the microstructure of alloy powder was analysed by means of XRD and SEM,then the electromagnetic parameters characterization of alloy powder was used by vector network analyzer.The result shows that,the reflectivity of alloy powder was lower from 2 GHz to 7 GHz under 1.5 mm material thickness,especially at 5.3 GHz Fe₉₇Cr₃ alloy powder reflectivity was -17 dB.The reflectivity of Fe₉₇Cr₃alloy powder was systematically reseached,the result shows that the least reflectivity frequency was moved from high frequency to low frequency by increasing material thickness.The reflectivity of Fe₉₇Cr₃ alloy powder was least at 2.5 mm material thickness,at 3 GHz its reflectivity was -42 dB.

Key words: microwave absorbing material, mechanical alloying, Fe-Cr alloy