Soft magnetic composite base on ferromagnetic core and NiFe2O4 shell

0435594 - ÚFM 2015 RIV SK eng A - Abstrakt
Strečková, M. - Hadraba, Hynek - Roupcová, Pavla - Bureš, R.
Soft magnetic composite base on ferromagnetic core and NiFe2O4 shell.
Deformation and fracture in PM materials DFPM2014. Košice: Institute of Materials Research of the Slovak Academy of Sciences in Košice, Slovak Republic, 2014 - (Beata Ballóková; Katarína Ondrejová; Marcela Selecká). s. 31. ISBN 978-80-970964-8-9.
[DF PM 2014 Internatinal Conference Deformation and Fracture in PM Materials. 26.10.2014-29.10.2014, Stará Lesná]
Grant CEP: GA ČR(CZ) GA14-25246S
Institucionální podpora: RVO:68081723
Klíčová slova: soft magnetic composite * spinel ferrite * FeSi * Permalloy type particles
Kód oboru RIV: JG - Hutnictví, kovové materiály

Soft magnetic composite (SMCs) are basically designed as a ferromagnetic powder surrounded by thin electrically insulating layer. The formed dielectric layer may have an organic or inorganic nature. The advantage of widely use of organic binders lie in the smart preparation of composites, high density of final green compacts but the thermal treatment temperature is strictly limited by the thermal resistance of the organic insulating material which is not high enough for removing some plastic deformation creates after compaction step in the green compact. The sufficient heat treatment permits low volume fractions of defects, reduce the distortion within the particles, lowers the dislocation density and thereby increase the magnetic permeability. To achieve this purpose, electrically resistant materials, for example the spinel ferrites with acceptable magnetic properties are suitable candidates for SMCs preparation. In the present work, the spinel nickel ferrite NiFe2O4 was created on FeSi and Permalloy type particles by precipitation of chloride precursors from alkaline solution. The modified preparation of NiFe2O4 ferrite coating was synthesized by low temperature route, withouth any surfactant and multiple steps directly on the ferromagnetic powder. The created layer was extracted by FIB and examined by SEM, TEM and XRD analysis. The final powder was compacted at 400 MPa by one axis compression and the electrical resistivity was studied.
Trvalý link: http://hdl.handle.net/11104/0239686