Co-Ni-Zn Ferrites Fabricated by Spark Plasma Sintering

Abstract

Ni0,4Co0,2Zn0,4Fe2O4 spinel ferrites have been synthesized by precipitation method from an aqueous solution and bulk samples were fabricated by Spark Plasma Sintering (SPS) to investigate the microstructure and the mechanical properties. Although SPS is considered as a rapid compaction technique, its application is uncommon for ferrites due to reactions occurring between the graphite die and the ferrite powder at elevated temperature. In our tests this problem was circumvented by an alumina film applied on the die. We found that both chemical and phase composition could be retained in the sintered specimens after sintering. In addition, they exhibited improved mechanical properties in terms of hardness (10 GPa) and fracture toughness (2.7 MPa · m−1/2) as compared to conventionally sintered reference samples.