Nanosize Ni0,7Zn0,3Fe2O4 powders prepared by combustion synthesis, sintering and characterization

Nanosize Ni-Zn ferrite powders (Ni0,7Zn0,3Fe2O4) have been prepared by combustion synthesis using nitrates and urea as fuel. The resulting powders were characterized by X-ray diffractometry (XRD), BET, scanning electron microscopy (SEM), and helium pycnometry. The results showed that it is possible to obtain nanosize Ni-Zn ferrite powders with high specific surface area (63,89 m(2)/g). The powders showed extensive XRD line broadening and the crystallite size calculated from the XRD line broadening was 18,6 nm. The samples were uniaxially compacted by dry pressing and sintered at 1200degreesC/2h and characterized by bulk density, SEM and magnetic properties. The samples showed uniform microstructures with a small grain size (3,0 mum), high density (98% TD), maximum flux density (0,33 T) and coercive force (168,4 A/m).