Grain size and coercivity tuning in Nd2Fe14B-based magnets prepared by high pressure hydrogen milling
New publication
2023/07/19
I. Dirba, A. Aravindhan, M. Muneeb, O. Gutfleisch
High-performance Nd2Fe14B -based permanent magnets are vital for emerging green technologies such as direct-drive generators in wind turbines or motors for hybrid and electric vehicles. High coercivity at elevated operating temperatures is crucial for device performance and is largely determined by the microstructure of the magnet. In this work, we use high pressure hydrogen milling to reduce the average grain size in Nd2Fe14B powders towards the critical single domain regime to study the influence on the resultant coercivity.
• High pressure hydrogen milling was successfully used to produce Nd2Fe14B-based magnets with grain size tunable several orders of magnitude from below single domain regime (<200 nm) up to tens of μm.
• Coercivity peaks around the analytically calculated single domain grain size of ≈200 nm for Nd2Fe14B.
• Higher contents of Nd-rich grain boundary phase lead to a continuous increase in coercivity up to μ0Hc=1.5 T.
J. Magn. Magn. Mater. 582 (2023) 171018.
