Microwave absorption properties regulation and bandwidth formula of oriented Y₂Fe₁₇N_3-δ@SiO₂/PU composite synthesized by reduction-diffusion method

As concepts closely related to microwave absorption properties, impedance matching and phase matching were rarely combined with material parameters to regulate properties and explore related mechanisms. In this work, reduction-diffusion method was innovatively applied to synthesize rare earth alloy Y_2Fe_17. In order to regulate the electromagnetic parameters of absorbers, the Y_2Fe_17N_3-\delta particles were coated with silica (Y_2Fe_17N_3-\delta @SiO_2) and absorbers with different volume fractions were prepared. The relationship between impedance matching, matching thickness, and the strongest reflection loss peak (\rm RL_\rm min) was presented obviously. Compared to the microwave absorption properties of Y_2Fe_17N_3-\delta /PU absorber, Y_2Fe_17N_3-\delta @SiO_2/PU absorbers are more conducive to the realization of microwave absorption material standards which are thin thickness, light weight, strong absorbing intensity, and broad bandwidth. Based on microwave frequency bands, the microwave absorption properties of the absorbers were analyzed and the related parameters were listed. As an important parameter related to perfect matching, reflection factor (\sqrt ărepsilon_\rm r/\mu_\rm r) was discussed combined with microwave amplitude attenuation. According to the origin and mathematical model of bandwidth, the formula of EAB (\rm RL<-10 dB) was derived and simplified. The calculated bandwidths agreed well with experimental results.