ZrNi–H2: microstructural analysis of the thermodynamically controlled hydride phase growth, and electronic properties

Structure and interstitial deuterium sites ofβ-phase ZrNi deuteride

“…[17][18][19][20] Numerous studies have suggested that the ␣-phase ZrNi metal lattice retains essentially the same structure ͑Cmcm symmetry͒ during hydrogen absorption, forming ␤-phase ZrNiH ͑i.e., monohydride͒ and ␥-phase ZrNiH 3 ͑i.e., trihydride͒. [1][2][3][4]6 The structure and interstitial occupancies of ␥-ZrNiH 3 have been exhaustively studied, 2,6,12 and all the experimental results agree well with the model first proposed by Westlake. 7 For ␤-ZrNiH, an early neutron powder diffraction ͑NPD͒ study 3 and a more recent x-ray diffraction ͑XRD͒ study 6 both favored a structure ͑␣, ␤, ␥ within the vicinity of 90°͒ that can be derived by slightly distorting the Cmcm-symmetric structure.…”

Magic-angle spinning NMR study of deuterium site occupancy and dynamics inZrNiD1.0andZrNiD3.0Adolphi1, Badola2, Browder3 et al. 2001Phys. Rev. B18030View full textAdd to dashboardCite

“…Furthermore, the identity of the secondary phase was not apparent in the room-temperature x-ray spectra, which may indicate that the secondary phase is present in larger quantities at lower temperatures ͑where we can observe it in the NMR spectra͒. Although the starting material is known to have contained a small amount of Zr 9 Ni 11 , 14,15 this phase does not absorb hydrogen under the same conditions as ZrNi, 15,43,44 and is therefore not likely to be the source of the impurity phase peak in the 2 H NMR spectra.…”

“…5,[10][11][12][13][14][15] The compound has also been favorably evaluated for a number of technological applications including tritium handling and storage, 11,16,17 closed-cycle Joule-Thomson refrigerators used to form solid H 2 at 10 K, 18 -21 and reversible gas-gap thermal switches. [22][23][24] One of our interests in studying the ZrNiD x system was to further develop 2 H magic-angle spinning nuclear magnetic resonance ͑MAS-NMR͒ spectroscopy as a tool for determining interstitial site occupancy and rates of motion in metaldeuterium systems.…”

Degradation study of ZrNiH1.5 for use as actuators in gas gap heat switches

“…The measured composition of this ingot essentially matched the ideal Zr/Ni ratio of 1.0. Detailed microscopic and X-ray diffraction examinations have been performed by Michel et al [39] on a portion of this same ZrNi ingot. They reported the material was the orthorhombic ZrNi-phase with a high density of twinning defects and a minor secondary phase of composition Zr 9 Ni 11 , which lies along the grain boundaries of the host matrix.…”