Preparation of Fe@Fe<sub>3</sub>O<sub>4</sub>/ZnFe<sub>2</sub>O<sub>4</sub> Powders and Their Consolidation via Hybrid Cold-Sintering/Spark Plasma-Sintering
Amalia Mesaros,
Bogdan Viorel Neamțu,
Traian Florin Marinca,
Florin Popa,
Gabriela Cupa,
Otilia Ruxandra Vasile,
Ionel Chicinaș
Affiliations
Amalia Mesaros
Physics and Chemistry Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca, Romania
Bogdan Viorel Neamțu
Materials Science and Engineering Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca, Romania
Traian Florin Marinca
Materials Science and Engineering Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca, Romania
Florin Popa
Materials Science and Engineering Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca, Romania
Gabriela Cupa
Materials Science and Engineering Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca, Romania
Otilia Ruxandra Vasile
Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Chemical Engineering and Biotechnologies, National University of Science and Technology Politehnica Bucharest, No 1-7 Polizu Street, S1, 060042 Bucharest, Romania
Ionel Chicinaș
Materials Science and Engineering Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca, Romania
Our study is focused on optimizing the synthesis conditions for the in situ oxidation of Fe particles to produce Fe@Fe3O4 core–shell powder and preparation via co-precipitation of ZnFe2O4 nanoparticles to produce Fe@Fe3O4/ZnFe2O4 soft magnetic composites (SMC) through a hybrid cold-sintering/spark plasma-sintering technique. XRD and FTIR measurements confirmed the formation of a nanocrystalline oxide layer on the surface of Fe powder and the nanosized nature of ZnFe2O4 nanoparticles. SEM-EDX investigations revealed that the oxidic phase of our composite was distributed on the surface of the Fe particles, forming a quasi-continuous matrix. The DC magnetic characteristics of the composite compact revealed a saturation induction of 0.8 T, coercivity of 590 A/m, and maximum relative permeability of 156. AC magnetic characterization indicated that for frequencies higher than 1 kHz and induction of 0.1 T, interparticle eddy current losses dominated due to ineffective electrical insulation between neighboring particles in the composite compact. Nevertheless, the magnetic characteristics obtained in both DC and AC magnetization regimes were comparable to those reported for cold-sintered Fe-based SMCs.
