Mechanical properties of Fe-Si and Ni-Fe core-shell particles coated by NiFe2O4 ferrite

0450433 - ÚFM 2016 RIV SK eng A - Abstrakt
Hadraba, Hynek - Strečková, M. - Husák, Roman
Mechanical properties of Fe-Si and Ni-Fe core-shell particles coated by NiFe2O4 ferrite.
Book of Abstracts: International Conference Fractografia/Fractography 2015. Košice: SAV, 2015.
[International Conference Fraktografia/Fractography 2015. 18.10.2015-21.10.2015, Stará Lesná]
Grant CEP: GA ČR(CZ) GA14-25246S; GA MŠMT(CZ) ED1.1.00/02.0068
Institucionální podpora: RVO:68081723
Klíčová slova: soft magnetic composite * ferrite * superalloy
Kód oboru RIV: JG - Hutnictví, kovové materiály

The core-shell particles were prepared by coating Fe-Si and Ni-Fe particles with NiFe2O4 ferrite. NiFe2O4 cuboidal nanoparticles were directly deposited onto particle´s surface by the chemical precipitation of hydroxides by alkaline treatment of the dissolved metal in aqueous chloride solution. The deposited coating consisted of two concentric layers: dense one adherent to the particle´s surface and particulate one forming outer shell of the particle. The mechanical properties of coated particles were studied by means of instrumented indentation. The indentation hardness of Fe-Si and Ni-Fe particles was about 6GPa and 10GPa, respectively. The hardness of dense ferrite layer was about 9GPa while hardness of particulate outer shelf was about 2GPa. Due to silica/silicides interlayer developed onto surface the nature of Fe-Si core-shell particle response to mechanical loading was brittle. Even under low loading up-to 1mN by Berkovich indentor, the cracks induced from corners of indentor imprint propagated from layer towards Fe-Si surface and caused separation of layer from Fe-Si surface. This behaviour was not observed in the case of Ni-Fe core-shell particles.
Trvalý link: http://hdl.handle.net/11104/0252453