Saldan I. Synthesis, structure and properties of oxygen-stabilized ?-phases based on titanium and zirconium

The full-profile Rietveld analysis of X-ray and neutron diffraction data was used for determination of crystal structure of Zr3V3O0.6D9.6 and Ti3ZrNi2O0.3D6.2 deuterides. The X-ray phase analysis for Zr3-xTixV3-yNiyO0.6 alloys the (0Јx, yЈ1,5) and their hydrides revealed that the main phase of the alloys is the oxygen-stabilized ?-phase, with exception of Zr2TiV3O0.6 and Zr1.5Ti1.5V3O0.6. The existence of the continuous solid solution between the Ti4Ni2Ох and Zr4Ni2Ох compounds at 1273 К with the ?-Fe3W3C-type structure had been shown for the first time. The rise in the oxygen concentration in the Ті4-хZrxNi2Oy alloys (0,2ЈхЈ0,6; 0,2ЈyЈ1,0) is shown to be accompanied by a gradual drop in the amount of hydrogen absorbed from gaseous phase, but the part of electrochemically absorbed hydrogen can substantially increase and exceed 90 % of theoretically possible amount. The oxygen-modified and V-substituted alloys on the basis of the Ti2Ni one are characterized by high cyclic stability, which can be explained by both higher corrosion resistance and the rise in the stability against disproportionation during the formation of oxygen-stabilized ?-phases. The HDDR treatment of the Ti4Ni2O0.3 alloy was for the first time shown to lead to the improvement of microstructure homogeneity of hydrogen absorbing materials and, in its turn, to the 30% rise in the discharge capacity and cycling life during charge-discharge cycling.