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Fe-Co-B Soft Magnetic Ribbons: Crystallization Process, Microstructure and Coercivity

Authors :
Anna Wojcik
Wojciech Maziarz
Maciej Kowalczyk
Robert Chulist
Maciej Szlezynger
Pawel Czaja
Lukasz Hawelek
Przemyslaw Zackiewicz
Patryk Wlodarczyk
Aleksandra Kolano-Burian
Source :
Materials, Vol 13, Iss 7, p 1639 (2020)
Publication Year :
2020
Publisher :
MDPI AG, 2020.

Abstract

In this work, a detailed microstructural investigation of as-melt-spun and heat-treated Fe67Co20B13 ribbons was performed. The as-melt-spun ribbon was predominantly amorphous at room temperature. Subsequent heating demonstrated an amorphous to crystalline α-(Fe,Co) phase transition at 403 °C. In situ transmission electron microscopy observations, carried out at the temperature range of 25–500 °C and with the heating rate of 200 °C/min, showed that the first crystallized nuclei appeared at a temperature close to 370 °C. With a further increase of temperature, the volume of α-(Fe,Co) crystallites considerably increased. Moreover, the results showed that a heating rate of 200 °C/min provides for a fine and homogenous microstructure with the α-(Fe,Co) crystallites size three times smaller than when the ribbon is heated at 20 °C/min. The next step of this research concerned the influence of both the annealing time and temperature on the microstructure and coercivity of the ribbons. It was shown that annealing at 485 °C for a shorter time (2 s) led to materials with homogenous distribution of α-(Fe,Co) crystallites with a mean size of 30 nm dispersed in the residual amorphous matrix. This was reflected in the coercivity (20.5 A/m), which significantly depended on the volume fraction of crystallites, their size, and distribution.

Details

Language :
English
ISSN :
19961944
Volume :
13
Issue :
7
Database :
Directory of Open Access Journals
Journal :
Materials
Publication Type :
Academic Journal
Accession number :
edsdoj.64ba1dea754160a2e2fe693a373627
Document Type :
article
Full Text :
https://doi.org/10.3390/ma13071639