New FCC Mg–Zr and Mg–Zr–ti deuterides obtained by reactive milling

Abstract

Hydrogen storage, mechanical alloying, reactive milling, metal hydrides, powder X-ray and neutron diffractionResults for binary Mg-Zr and ternary Mg-Zr-Ti mixtures ball milled at room temperature under reactive deuterium atmosphere (5.6-6.7 MPa) are reported. X-ray and neutron powder diffraction combined with Rietveld refinements show that two new cubic phases were formed during

Phase Transformations in MgH2–TiH2 Hydrogen Storage System by High‐Pressure Torsion Process

“…Since the HPT method introduces shear strain under high pressure, it can synthesize the hydrides within shorter time compared with other mechanochemical synthesis methods. [87,88] Moreover, a recent study using the neutron diffraction method showed that the Ti-rich Mg-Ti-H hydrides synthesized by ball milling consist of the γ-MgH 2 clusters in the FCC-TiH 2 matrix, [33] but the current study confirms that a real atomic-scale mixing and the formation of metastable FCC Mg-Ti-H hydride occurs by HPT processing.…”

“…Although the metastable Mg–Ti–H FCC hydrides were already synthesized by ball milling or thin film sputtering, this study together with a few earlier publications suggests the potential of ultra‐SPD via the HPT processing as an alternative to other mechanochemical processing methods such as ball milling to produce ternary hydrides even from the immiscible systems. Since the HPT method introduces shear strain under high pressure, it can synthesize the hydrides within shorter time compared with other mechanochemical synthesis methods . Moreover, a recent study using the neutron diffraction method showed that the Ti‐rich Mg–Ti–H hydrides synthesized by ball milling consist of the γ ‐MgH 2 clusters in the FCC–TiH 2 matrix, but the current study confirms that a real atomic‐scale mixing and the formation of metastable FCC Mg–Ti–H hydride occurs by HPT processing.…”

Nanostructural Perspective for Destabilization of Mg Hydride Using the Immiscible Transition Metal Mn

“…Synthesizing other immiscible Mg–X (X: Zr, V, etc.) alloys and their hydrogenation/dehydrogenation properties have also been reported. − Among the immiscible Mg systems, Mg–Mn alloys are attractive because of the low material costs. However, the enthalpy for deuteride dissociation of the Mg 0.25 Mn 0.75 –D powder was found to be Δ H = 71.5 kJ mol –1 –D 2 , not much different from the value Δ H = 73.1 kJ mol –1 –D 2 (Δ H = 74.4 kJ mol –1 –H 2 ) found for conventional bulk Mg–D­(H) .…”