Studies of sintered MRE-Fe-B magnets by DyF₃ addition or diffusion treatment (MRE = Nd + Y + Dy)

Journal Article · Tue Mar 13 00:00:00 EDT 2012 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3679465· OSTI ID:1045816

Tang, W. ^[1]; Dennis, K. W. ^[1]; Kramer, M. J. ^[1]; Anderson, I. E. ^[1]; McCallum, R. W. ^[1]

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1. Ames Laboratory, and Iowa State University, Ames, IA (United States)

Sintered MRE₂(Fe, Co)₁₄B magnets by DyF₃ blending or diffusion treatment were investigated. “Base-line” magnets with a thickness of 1.5 mm were coated (painted) with DyF₃ powder and heated to promote Dy diffusion at 800–900 °C, i.e., “Diffusion” magnets. For comparison, the magnet alloy powder for making Base-line magnets was blended with 3–5 wt.% DyF₃ powder and then made into sintered magnets, i.e., “Blended” magnets. The coercivity and (BH)_max of Base-line magnets were 9.7 kOe and 32.7 MGOe, respectively, while the coercivity of Diffusion magnets was increased to 15 kOe and the (BH)_max was nearly unchanged at 31.4 MGOe. Blended magnets with 5 wt% DyF₃ had a coercivity of 17.8 kOe, but the (BH)_max was reduced to 25.4 MGOe, due to a considerable reduction of remanence. The total Dy concentration in the MRE₂(Fe, Co)₁₄B Diffusion magnets with a β value of -0.5%/°C was 5.3 wt%, while typical commercial Nd-based Nd₂Fe₁₄B magnets require at least 7.5 wt% Dy to achieve the same β. Therefore, the MRE₂(Fe, Co)₁₄B Diffusion magnets exhibited better temperature stability.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Vehicle Technologies Office (VTO)
• Grant/Contract Number: AC02-07CH11358
• OSTI ID: 1045816
• Report Number(s): IS-J-7704
• Journal Information: Journal of Applied Physics, Vol. 111, Issue 7; ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
temperature coefficient
crystallographic defects
magnetic anisotropy
magnetic equipment
magnetic materials
grain boundary diffusion
magnetic fields
materials synthesis and processing
materials properties