ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Hydrogen absorption and disproportionation of melt-spun Nd–Fe–B-based ribbons are significantly affected by quench state (wheel speed). The initial hydrogen absorption temperature corresponding to the formation of the Nd2Fe14BHx-type phase shifts from ∼120 °C for ingot to 250–300 °C for ribbons spun at 13, 15, 17, 20, 22, and 24 m/s wheel speeds. This shift is presumably related to the fact that ribbons are considerably more inert than ingot, which is typical of Nd–Fe–B materials. The hydrogen disproportionation temperature, however, monotonically decreases with increasing wheel speed from (approximately-greater-than)700 °C for ingot to 530 °C for 24 m/s ribbons. Hydrogen absorption due to disproportionation exhibits a two-step feature for wheel speeds ≥20 m/s. The onset and size of the lower temperature step correlates with the presence and amount of an amorphouslike component in the x-ray diffraction spectra of as-spun ribbons. The amorphouslike component is detectable only for wheel speeds ≥20 m/s, and both the amount of amorphouslike component and the size of the lower temperature step in the hydrogen absorption increase with increasing wheel speed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.355317
