Solid-state phase transformation in nanocrystalline R{sub 2}Fe{sub 17}C{sub x} compounds (R = Sm or Nd; x = 0--1)
- McGill Univ., Montreal, Quebec (Canada)
A solid-state phase transformation (SSPT) is observed in nanocrystalline Sm{sub 2}Fe{sub 17}C{sub x}, x = 0-1 (Th{sub 2}Zn{sub 17}-type carbides) prepared by both ball milling and rapid solidification. Upon annealing at 800 C the Sm{sub 2}Fe{sub 14}C (Nd{sub 2}Fe{sub 14}B-type) phase is formed for x {ge} 0.3. For x between 0.3 and 1.0, the Sm{sub 2}Fe{sub 17}C{sub y} (y {approximately} 0.3) and Sm{sub 2}Fe{sub 14}C phases co-exist. The process of the SSPT to Sm{sub 2}Fe{sub 14}C is faster in finer-grain samples. The annealing time required for a complete transformation varies from 15 min for a sample with an average grain size of 40 nm to 28 n for a 200 nm grain size sample. These results suggest that the SSPT is made accessible by reducing the grain sizes. Studies on Nd{sub 2}Fe{sub 17}O{sub 1.0} show that certain nd{sub 2}Fe{sub 14}C powders synthesized through SSPT contain highly anisotropic particles, suggesting a promising technique to produce anisotropic Nd{sub 2}Fe{sub 14}B-type permanent magnets.
- OSTI ID:
- 400776
- Report Number(s):
- CONF-960425--
- Journal Information:
- IEEE Transactions on Magnetics, Journal Name: IEEE Transactions on Magnetics Journal Issue: 5Pt2 Vol. 32; ISSN IEMGAQ; ISSN 0018-9464
- Country of Publication:
- United States
- Language:
- English
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