A study of hydrogen diffusion in hexagonal YHx single crystals (x≤0.10) by mechanical spectroscopy

181Ta perturbed-angular-correlation study of electric quadrupole interactions in yttrium metal and yttrium-hydrogen solid solutions

“…For x = 0.15 the activation energy is the same within this error interval. This value is in good agreement with previous results obtained by NMR and other techniques [16][17][18]. In the case of x = 0.20 a meaningful determination of E a was not possible because the fast fluctuation range investigated was too small.…”

Anelastic relaxation processes due to hopping of interstitial oxygen in scandium

“…Treatment 1 was performed in order to anneal the dislocations and outgas H in the "as received" material. The Q −1 (T) curve after this treatment (not reported here) shows that neither the relaxation of dislocations dragging interstitial H [4] nor the relaxation due to the formation/ dissolution of the H pairs [1,3] are present, whilst peak P-O1 is hardly detectable. The monotomic increase of the residual resistivity denotes a gaseous contamination of the sample with the thermal treatments.…”

“…Regarding the origin of P-O2, a possibility is a mechanism similar to that occurring with H in the hcp rare earths [3], namely a Zener-type formation and dissolution of H pairs along the c axis in T sites adjacent to a same metal atom. The stability of such paired configuration has been recently put into relation with the influence of interstitial H on the electronic system [10].…”

“…Anelastic spectroscopy measurements have revealed an unexpectedly rich relaxation spectrum in Y and Sc, in the temperature range 1-600 K, eight processes occur [2][3][4][5][6], even in samples which are generally considered pure. The processes around and below room temperature are all due to hydrogen motion either in free state or interacting with trapping impurities and dislocations [2][3][4][5][6].…”

“…The processes around and below room temperature are all due to hydrogen motion either in free state or interacting with trapping impurities and dislocations [2][3][4][5][6]. Instead, the processes above room temperature, which appear also in pure samples, should be presumably ascribed to oxygen relaxation.…”