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Keywords: PIM Ni-Zn ferrites Mechanical properties Magnetic propertiesNowadays, the electronic industry demands small and complex parts as a consequence of the miniaturization of electronic devices. Powder injection moulding (PIM) is an emerging technique for the manufacturing of magnetic ceramics. In this paper, we analyze the sintering process, between 900 °C and 1300 °C, of Ni-Zn ferrites prepared by PIM. In particular, the densification behaviour, microstructure and mechanical properties of samples with toroidal and bar geometry were analyzed at different temperatures. Additionally, the magnetic behaviour (complex permeability and magnetic losses factor) of these compacts was compared with that of samples prepared by conventional powder compaction. Finally, the mechanical behaviour (elastic modulus, flexure strength and fracture toughness) was analyzed as a function of the powder loading of feedstock. The final microstructure of prepared samples was correlated with the macroscopic behaviour. A good agreement was established between the densities and population of defects found in the materials depending on the sintering conditions. In general, the final mechanical and magnetic properties of PIM samples were enhanced relative those obtained by uniaxial compaction.

The electrical properties of polycrystalline NiZn ferrite, Zn 0.44 Ni 0.38 Fe 2.18 O 4 , were investigated by impedance spectroscopy over the frequency and temperature ranges, 5 Hz to 2 MHz and 10 to 600 K and by magnetic permeability measurements at room temperature. Samples were sintered in either conventional or solar furnaces followed by quenching or slow cooling to ambient temperature. Depending on processing conditions, the room temperature electrical resistivity of conventionally-sintered samples varied by seven orders of magnitude, from 5 ohm cm for a sample Samples sintered in the solar furnace were much more conductive than ones that were slowcooled after conventional sintering and this is attributed to the relatively rapid cooling rate after exposure in the solar furnace, which preserved some of the oxygen deficiency present at high temperature. For the same reason, samples that were slow cooled in N 2 were also much more conductive. For conventionally-sintered samples of similar density, quenched samples had much higher imaginary permeability, attributed to their lower resistivity and higher eddy currents, than slow-cooled samples. Solar-sintered samples had higher real permeability than slow-cooled, conventionally-sintered ones mainly due to a combination of their lower resistivity and higher density, 96% compared to 86%.