TY - JOUR
T1 - Preparation of high-coercivity magnetic powder via heat treatment of a rapidly quenched amorphous starting compound with a THMN12 structure
AU - Kuno, Tomoko
AU - Yamamoto, Takahide
AU - Urushibata, Kimiko
AU - Kobayashi, Kurima
AU - Sugimoto, Satoshi
N1 - Funding Information:
This paper is based on results obtained from the future pioneering program “Developments of magnetic materials technology for high efficiency motors” commissioned by the New Energy and Industrial Technology Development Organization (NEDO).
Publisher Copyright:
© 2020 The Japan Institute of Metals and Materials.
PY - 2020
Y1 - 2020
N2 - Amorphous (Sm0.8Zr0.2)1.1(Fe0.9Co0.1)11.3Ti0.7 samples prepared by the rapid-quenching method were annealed under various conditions (8481223 K and 160 min) in a pure Ar atmosphere (PO2 < 1012 Pa). The powders obtained at low annealing temperatures (<1073 K) were predominantly composed of the 1-9 phase (SmFe9), whereas those obtained at high annealing temperatures (>1123 K), were mostly composed of the 1-12 phase (ThMn12). However, the highest coercivity (Hc) of more than 400 kAm11 (5 kOe) was observed for samples containing a mixture of the 1-9 and 1-12 phases, which were obtained by annealing at intermediate temperatures of 11231173 K for 1030 min. Domain structure observations revealed that the sample with the highest Hc (magnetic anisotropy field (Ha) of approximately 6 MAm11) was composed of single-domain particles. Moreover, Hc was decreased to approximately 160 kAm11 (2 kOe) by the formation of a domain structure (approximately 500 nm in width) in samples of the 1-12 mono-phase, despite high Ha of approximately 9 MAm11. A mechanism for these coercivity variations is proposed.
AB - Amorphous (Sm0.8Zr0.2)1.1(Fe0.9Co0.1)11.3Ti0.7 samples prepared by the rapid-quenching method were annealed under various conditions (8481223 K and 160 min) in a pure Ar atmosphere (PO2 < 1012 Pa). The powders obtained at low annealing temperatures (<1073 K) were predominantly composed of the 1-9 phase (SmFe9), whereas those obtained at high annealing temperatures (>1123 K), were mostly composed of the 1-12 phase (ThMn12). However, the highest coercivity (Hc) of more than 400 kAm11 (5 kOe) was observed for samples containing a mixture of the 1-9 and 1-12 phases, which were obtained by annealing at intermediate temperatures of 11231173 K for 1030 min. Domain structure observations revealed that the sample with the highest Hc (magnetic anisotropy field (Ha) of approximately 6 MAm11) was composed of single-domain particles. Moreover, Hc was decreased to approximately 160 kAm11 (2 kOe) by the formation of a domain structure (approximately 500 nm in width) in samples of the 1-12 mono-phase, despite high Ha of approximately 9 MAm11. A mechanism for these coercivity variations is proposed.
KW - Coercivity
KW - Domain structure formation
KW - Heat treatment
KW - Rapid-quenched powder
KW - Single-domain particles
KW - ThMn structure
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U2 - 10.2320/matertrans.MT-M2019356
DO - 10.2320/matertrans.MT-M2019356
M3 - Article
AN - SCOPUS:85082401115
SN - 1345-9678
VL - 61
SP - 657
EP - 662
JO - Materials Transactions
JF - Materials Transactions
IS - 4
ER -