Comparison of different methods to produce dense zinc ferrite ceramics with high electrical resistance

Three different methods were used to produce dense ZnFe2O4 ceramics with high electrical resistance – spray pyrolysis (SP), conventional sintering (CS) and spark plasma sintering (SPS). The phase purity was determined by X-ray diffraction and the morphology/particle size investigated by scanning electron microscopy. It was found that SP is the most appropriate method to produce a dense ZnFe2O4 ceramics with high electrical resistivity. By using the SP method, about 500 nm thick ZnFe2O4 films were obtained possessing a resistivity with 7 orders of magnitude higher than resistivity of ZnFe2O4 pellet sintered by SPS. Both samples obtained by SP and SPS show density close to the theoretical value. The sample obtained by CS shows a low resistivity and relatively high porosity.