Microstructure, magnetic and mechanical properties of Ni–Zn ferrites prepared by powder injection moulding

Nowadays, 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.

Graphical AbstractThe application of Powder Injection Molding to Ni–Zn ferrites allowed obtaining samples with density, magnetic and mechanical properties improved in relation to those obtained by uniaxial pressure compaction. Different powder loadings were tested. The best mechanical performance was achieved for 55 vol.%, while samples prepared with 58% powder loading present the higher magnetic properties.Figure optionsDownload as PowerPoint slideResearch highlights
► PIM samples density and magnetic permeability is higher than uniaxial pressing samples.
► Highest density and elastic modulus was achieved in 55% PIM samples.
► Highest flexural Strength and fracture toughness was achieved in 52% PIM samples.