Magnetic hardening of Ce_1+xFe_11–yCo_yTi with ThMn₁₂ structure by melt spinning

Journal Article · Wed Apr 15 04:00:00 UTC 2015 · Journal of Applied Physics

DOI: https://doi.org/10.1063/1.4918562 · OSTI ID:1227303

Zhou, Chen  ^[1]; Sun, Kewei ^[2]; Pinkerton, Frederick E. ^[3]; Kramer, M. J. ^[2]

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1. MEDA Engineering and Technical Services LLC, Southfield, MI (United States)
2. Iowa State Univ., Ames, IA (United States)
3. General Motors R&D Center, Warren, MI (United States)

A recent study on the intrinsic magnetic properties of CeFe_11–yCo_yTi has revealed that substituting one Co for Fe retains the favorable magnetocrystalline anisotropy H_a found in the ternary Fe end member, while enhancing the Curie temperature T_c and saturation magnetization 4πM_s. These findings warrant further optimization around Co substitution y = 1 to try to exploit the hard magnetic properties of these Ce-based magnets. Both Ce and Co concentrations in Ce_1+xFe_11–yCo_yTi have been optimized in the range of x = 0 – 0.2 and y = 0 –1.5. It was found that Co substitution effectively enhances all hard magnetic properties, although the values are still lower than those predicted from the intrinsic magnetic properties. Specifically, T_c increases from 210 °C to 285 – 350 °C; 4πM₁₉ (magnetization at 19 kOe) from 8.9 kG to 10.5 – 11.5 kG, remanence Br from 3.1 kG to 4.1 – 4.5 kG, and most importantly, H_ci from 1.1 kOe to 1.5 kOe. As a result, the room temperature energy product (BH)_max has been increased by over 100% from 0.7 MGOe in Ce_1.1Fe₁₁Ti to 1.5 MGOe in Ce_1.05Fe_9.75Co_1.25Ti. Microscopy analysis indicates that the addition of Co refines the grain size and promotes chemical homogeneity at the microscopic scale. As a result, the beneficial effect of Co on the microstructure contributes to the improved hard magnetic properties.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-07CH11358
• OSTI ID: 1227303
• Report Number(s): IS-J--8688
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 17 Vol. 117; ISSN JAPIAU; ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English