Hydrogen diffusion in DyFe2 and its effect on magnetic properties

[摘要] For the DyFe2 Laves phase intermetallic compound, the nature of hydrogen-induced amorphization, structural changes and the dynamic behavior of hydrogen atoms were studied by means of X-ray diffraction, magnetic after-effect and thermal desorption spectrometry. DyFe2 can be amorphized by hydrogen charging within the narrow temperature range between 523 K and 593 K, even at a low hydrogen pressure of 0.1 MPa. At lower temperatures, DyFe2 forms a crystalline hydride, whereas it decomposes into alpha-Fe and DyH2 at higher temperatures. From the relaxation spectra obtained in magnetic after-effect measurements, it is found that hydrogen atoms in the crystalline hydride occupy the tetrahedral interstitial sites consisting of DyFe3 and Dy2Fe2 with activation energies of short-range diffusion determined as 0.24 eV and 0.35 eV respectively. For the amorphous hydride, hydrogen atoms additionally occupy Dy3Fe sites with an activation energy of 0.43 eV, and the distribution of activation energies becomes broader.

[发布日期] 1995-12-15

[效力级别]  Proceedings Paper

[关键词] amorphization;diffusion;hydrogen;magnetic after-effect;susceptibility