Magnetic filter produced by ZnFe2O4 nanoparticles using freeze casting

Zinc ferrite magnetic nanoparticles were synthesized by combustion method and the obtained powders were processed by the freeze casting technique, to produce magnetic filters. Green bodies were obtained by freezing a water-based slurry of nanoparticles and polyethylene glycol (PEG) of molecular mass 8000. The suspension was frozen to −140 °C under the cooling rate of 10 °C/min. The obtained bodies were sintered at 1300 °C during 1 h and the X-ray diffraction (XRD) analyses showed ferrite as the only crystalline phase. Scanning electron microscopy (SEM) analyses revealed formation of porous channels in freezing direction and Archimedes’ density measurements showed porosity values ranging from 48.0% to 63.0%, depending on PEG content.