Abstract
We investigated the effects of Al/Cu co-doping on the magnetic and microstructural properties of a Nd-Fe-B sintered magnet. In particular, the structural and compositional changes of Cu-dissolved Nd-rich (Cu-rich) triple junction phase (TJP) and grain boundary phase (GBP) experienced upon Al/Cu co-doping were intensively analyzed. Al was selectively dissolved into the Culow-rich phases (B phase, 3–15 at.% Cu) other than the Cuhigh-rich phases (A phase, 20–45 at.% Cu). The B phase with an h-Nd2O3 structure was transformed to the C phase (Al-dissolved Culow-rich phases) with a c-Nd2O3 structure upon Al dissolution. In addition, the continuity of C GBP was improved and the Fe content of C GBP was reduced (25 → 5 at.% Fe). As a result, the coercivity (Hc) of the Al/Cu co-doped magnet was higher than that of a Cu-doped magnet. The critical role played by Al in improving the magnetic properties and microstructure of the Al/Cu co-doped magnet was elucidated. The detailed mechanism for the Hc enhancement of the Al/Cu co-doped magnet was discussed based on the results.
Original language | English |
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Pages (from-to) | 200-207 |
Number of pages | 8 |
Journal | Acta Materialia |
Volume | 133 |
DOIs | |
Publication status | Published - 2017 Jul |
Keywords
- Coercivity
- Grain boundaries
- Metastable phases
- Microstructures
- Nd-Fe-B sintered magnet
- Triple junctions
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys