Simple and reproducible preparation of barium hexagonal ferrite by adsorbent combustion method

Barium hexagonal ferrite BaZn ₂Fe ₁₆O ₂₇ was rapidly synthesized by adsorbent combustion method. The whole preparation time was controlled within 8 h. The microstructures were studied using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). The results showed that the pure BaZn ₂Fe ₁₆O ₂₇ was obtained after calcined at 1200 °C and the particles exhibited homogeneous hexagonal-plate shape with high aspect ratio. Moreover, the complex permeability (μr=μ′-jμ″) and the complex permittivity (r=′-j″) were measured in the frequency range of 8-12 GHz (X-band) and 12-18 GHz (K _u-band) using the network analyzer. The as-prepared ferrite exhibited strong magnetic loss properties. The microwave absorbing properties of the single BaZn ₂Fe ₁₆O ₂₇ ferrite layer with different thicknesses were also analyzed. The results showed that the minimum reflection loss was -15.3 dB and the bandwidth of reflection loss less than -10 dB reached 7.7 GHz with the absorber thickness only 1.7 mm. The adsorbent combustion method is a kind of ideal method to rapidly prepare barium hexagonal ferrite with excellent microwave absorbing properties.