TY - JOUR
T1 - Processing soft ferromagnetic metallic glasses
T2 - on novel cooling strategies in gas atomization, hydrogen enhancement, and consolidation
AU - Ciftci, N.
AU - Yodoshi, N.
AU - Armstrong, S.
AU - Mädler, L.
AU - Uhlenwinkel, V.
N1 - Funding Information:
This work was financially supported by the Industrielle Gemeinschaftsforschung IGF (Grant No. 19219 N/1 ) and the Japan Society for the Promotion of Science (Grant No. 18K04767 ). V. Uhlenwinkel and L. Mädler also greatly acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG)-Project (No. 276397488-SFB 1232) for partly supporting this research. This work was partly conducted at Tohoku University, Sendai, Japan and N. Ciftci appreciates the financial support through the following scholarships: MAPEX Center for Materials and Processes at the University of Bremen and the Cooperative Research and Development Center for Advanced Materials at Tohoku University (No. GIMRT-18GK0015). Dr. M. Wendschuh, Dr. S. Pokhrel, Dr. N. Ellendt, Prof. R. Busch, Dr. B. Bochtler, J. Eitzen, and L. Ludwig are acknowledged for their fruitful contributions. We are also grateful for the experimental and scientific support from E. Matthaei-Schulz, S. Evers, F. Peschel, K. Harata, and Dr. Z. Yan.
Publisher Copyright:
© 2020
PY - 2020/12/15
Y1 - 2020/12/15
N2 - Processing soft ferromagnetic glass-forming alloys through gas atomization and consolidation is the most effective technique to produce bulk samples. The commercial viability of these materials depends on commercial purity feedstock. However, crystallization in commercial purity feedstock is several orders of magnitude faster than in high purity materials. The production of amorphous powders with commercial purity requires high cooling rates, which can only be achieved by extending the common process window in conventional gas atomization. The development of novel cooling strategies during molten metal gas atomization on two model alloys ({(Fe0.6Co0.4)0.75B0.2Si0.05}96Nb4 and Fe76B10Si9P5) is reported. Hydrogen inducement during liquid quenching significantly improved the glass-forming ability and soft magnetic properties of {(Fe0.6Co0.4)0.75B0.2Si0.05}96Nb4 powders. Spark plasma sintering experiments verified that amorphous rings could be produced regardless of the cooling strategies used. While the saturation magnetization was almost unaffected by consolidation, the coercivity increased slightly and permeability decreased significantly. The magnetic properties of the final bulk samples were independent of feedstock quality. The developed cooling strategies provide a great opportunity for the commercialization of soft ferromagnetic glass-forming alloys with commercial purity.
AB - Processing soft ferromagnetic glass-forming alloys through gas atomization and consolidation is the most effective technique to produce bulk samples. The commercial viability of these materials depends on commercial purity feedstock. However, crystallization in commercial purity feedstock is several orders of magnitude faster than in high purity materials. The production of amorphous powders with commercial purity requires high cooling rates, which can only be achieved by extending the common process window in conventional gas atomization. The development of novel cooling strategies during molten metal gas atomization on two model alloys ({(Fe0.6Co0.4)0.75B0.2Si0.05}96Nb4 and Fe76B10Si9P5) is reported. Hydrogen inducement during liquid quenching significantly improved the glass-forming ability and soft magnetic properties of {(Fe0.6Co0.4)0.75B0.2Si0.05}96Nb4 powders. Spark plasma sintering experiments verified that amorphous rings could be produced regardless of the cooling strategies used. While the saturation magnetization was almost unaffected by consolidation, the coercivity increased slightly and permeability decreased significantly. The magnetic properties of the final bulk samples were independent of feedstock quality. The developed cooling strategies provide a great opportunity for the commercialization of soft ferromagnetic glass-forming alloys with commercial purity.
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U2 - 10.1016/j.jmst.2020.03.077
DO - 10.1016/j.jmst.2020.03.077
M3 - Article
AN - SCOPUS:85086886829
SN - 1005-0302
VL - 59
SP - 26
EP - 36
JO - Journal of Materials Science and Technology
JF - Journal of Materials Science and Technology
ER -