Synthesis of melt-spun rare-earth transition-metal intermetallics with Nd{sub 3}(Fe,Ti){sub 29} structure (abstract)
- Institute for Materials Science, NCRS Demokritos, 153 10 Ag. Paraskevi, Attiki (Greece)
- Instituto Materiali Speciali per Elettronica e Magnetismo, Via Chiavari 18/A 43100, Parma (Italy)
- Centro dil Studio per la Strutturistica Diffractometria del CNR, Viale delle Scienze, Parma (Italy)
Single phase ingots of Nd{sub 3}Fe{sub 27.5}Ti{sub 1.5} were prepared by argon arc melting followed by annealing at 1373 K for 72 h in evacuated sealed quartz tubes and water quenching. Pieces of the ingots were then made into ribbons using the spin-melting technique in argon atmosphere with velocities between 20{endash}40 m/s. The ribbon samples were annealed over a range of temperatures 723{endash}1323 K for times in the range 15{endash}50 min. The as-spun ribbons were found to be amorphous and presented a composition close to the nominal one. After annealing, the samples were crystallized and presented the Nd{sub 3}(Fe,Ti){sub 29}-type structure. From the relative intensities of the diffraction peaks it was concluded that the annealed samples presented texture. This was confirmed from the x-ray diffraction patterns of annealed ribbons after powdering which were similar to those of the bulk samples. The lattice parameters are: a=10.63(4) {Angstrom}, b=8.57(4) {Angstrom}, c=9.729(5) {Angstrom} and {beta}=97.01(2){degree}. Rietveld analysis on the annealed ribbons gave a composition of 60{percent} Nd{sub 3}(Fe,Ti){sub 29}, 21{percent} Nd(Fe,Ti){sub 12}, and 19{percent} {alpha}-Fe. Thermomagnetic analysis curves of the as-spun ribbons showed a broad transition between 373{endash}433 K and a secondary one at about 553 K indicating the presence of a 1:12 impurity. After annealing, the samples presented a Curie temperature typical for the Nd{sub 3}(Fe,T){sub 29} compound, 437 K and two secondary magnetic transitions characteristic for the 1:12 and {alpha}-Fe phases, respectively. The room temperature saturation magnetization, M{sub s}, was 145.0 and 138.7 emu/g before and after annealing, respectively. Scanning electron microscopy photographs of the annealed ribbons showed a grain size {lt}1 {mu}m and the microanalysis of the grains gave a mean stoichiometry Nd{sub 3}Fe{sub 24}Ti{sub 5} for the 3:29 phase. The coercivity of the annealed samples was 1 kOe at room temperature. (Abstract Truncated)
- OSTI ID:
- 554271
- Report Number(s):
- CONF-961141-; ISSN 0021-8979; TRN: 98:000878
- Journal Information:
- Journal of Applied Physics, Vol. 81, Issue 8; Conference: 41. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 12-15 Nov 1996; Other Information: PBD: Apr 1997
- Country of Publication:
- United States
- Language:
- English
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