Characterizing the ZrBe2Hx Phase Diagram via Neutron Scattering Methods

Hui Wu, Wei Zhou, Terrence J. Udovic, Robert C. Bowman Bowman, Bjørn C. Hauback
2022 Inorganics  
Since the initial assessment four decades ago of zirconium diberyllide, ZrBe2, as a potential hydride-forming intermetallic for hydrogen-storage applications, structural and dynamical studies to date have been chiefly limited to the hydride composition, ZrBe2H1.5, which exists as a single-phase disordered hydride with hexagonal P6/mmm symmetry that undergoes hydrogen sublattice ordering below ~200 K (~235–250 K for ZrBe2D1.5). It is desirable from both fundamental and technological viewpoints
more » ... have a more complete understanding of the ZrBe2Hx phase diagram. In the present study, both neutron powder diffraction and neutron vibrational spectroscopy measurements of ZrBe2Hx at lower hydrogen contents (x < 1.5) indicate that at least two other ordered phases exist at low temperatures, coinciding with respective nominal x values of 1 and 0.67. Compared to ZrBe2H1.5, these more-hydrogen-dilute phases possess different structural symmetries (orthorhombic) with different H-sublattice orderings and undergo much-higher-temperature order-disorder transitions at ≈460 K (x = 1) and ≈490 K (x = 0.67) to the characteristic H-disordered hexagonal P6/mmm structure associated with ZrBe2H1.5.
doi:10.3390/inorganics11010001 fatcat:4tb2mcxfofc2fkecrabqw2gcje