Title :
Enhanced remanence in flash-annealed Nd4Fe78B 18
Author :
Altoe, M.V.P. ; Lancarotte, M.S. ; Rechenberg, H.R. ; Missell, F.P. ; González, J.M.
Author_Institution :
Inst. de Fisica, Sao Paulo Univ., Brazil
fDate :
11/1/1995 12:00:00 AM
Abstract :
Nanocrystalline Nd4Fe78B18 was produced by affixing current leads directly to amorphous ribbons for flash-annealing. Ribbons were annealed in the range Ta=650-1000°C, for times 10-600 s. Flash-annealed ribbons show higher remanence ratios (Mr/Ms=0.83) than those submitted to conventional furnace (680°C/10 min) annealing (M r/Ms=0.74). In flash-annealed ribbons, Mossbauer spectroscopy and X-ray diffraction indicated the presence of the Nd2Fe23B3 phase, in addition to Fe3B, Nd2Fe14B, and α-Fe. Flash-annealing for short times at high temperatures may give Hc values up to 20% higher than furnace annealing. The isothermal remanent magnetization and the dc demagnetization remanence were found to be in reasonable agreement with the Wohlfarth relation
Keywords :
annealing; boron alloys; crystallisation; demagnetisation; ferromagnetic materials; iron alloys; nanostructured materials; neodymium alloys; permanent magnets; remanence; α-Fe; 10 to 600 s; 650 to 1000 C; Fe; Fe3B; Mossbauer spectroscopy; Nd2Fe14B; Nd2Fe23B3; Nd2Fe23B3 phase; Nd4Fe78B18; Wohlfarth relation; X-ray diffraction; amorphous ribbons; dc demagnetization remanence; enhanced remanence; flash-annealed Nd4Fe78B18; flash-annealing; high temperatures; isothermal remanent magnetization; nanocrystalline Nd4Fe78B18; remanence ratios; Amorphous materials; Annealing; Furnaces; Iron; Isothermal processes; Neodymium; Remanence; Spectroscopy; Temperature; X-ray diffraction;
Journal_Title :
Magnetics, IEEE Transactions on
