Kovalchuk I. New hydrides of stabilized intermetallic compounds based on Titanium, Zirconium and Hafnium

The dissertation is devoted to the study of processed sorption-desorption hydrogen by new and known IMC and alloys based on zirconium, titanium and hafnium. In particular, the crystal structure of deuterides of oxygen-stabilized compounds Zr3Fe(Co,Ni)Ox with Re3B type structure; deuterides of k-phase Zr9V4S and Hf9Mo4Si with Hf9Mo4B type structure; deuterides of oxygen-modified η-phases (Ti,Zr)4Fe2Oх and Hf4Fe2Ox with Ti2Ni type structure (η-Fe3W3C) have been investigated. For the first time the dependence of the hydrogen storage capacity of Zr3MOx (M  Fe, Co, Ni) compounds on the amounts of dissolved oxygen. The oxygen content decreases the ability to disproportionation Zr3FeOx compounds. The results of joint refinement the crystal structure by XRD and NPD patterns show that the incorporation of hydrogen atoms into the structure Zr3MOx (M  Fe, Co, Ni) compounds causes the movement of oxygen atoms from octahedral interstices to tetrahedral and trigonal bipyramidal interstices. After desorption deuterium the oxygen atoms return to their original interstices. According to the results of neutronographic studies of (Ti,Zr)4Fe2OхDy deuterides, it has been found that when the titanium is replaced by larger zirconium atoms in the structure of the compounds, the hydrogen atoms of the triangular faces begin to fill. The hydrogen lattice of all investigated hydrides  phases (Ti,Zr)4Fe2Oх and Hf4Fe2Oх is disordered. In addition to the effect on structure and hydrogen sorption capacity of the compounds, oxygen modification allows to influence their physicochemical properties. In particular, the addition of oxygen facilitates the activation of Ti–Fe alloys and reduce the tendency to disproportionation of Ti/Zr–Fe alloys in the process of hydrogen absorption–desorption. The existence of a continuous solid solution  Ti4-xZrxFe2Oy and wide homogeneity range for oxygen allow to purposefully change the hydrogen absorption characteristics from getters ( Zr4Fe2Ox) to typical hydrogen storage materials ( Ti4Fe2Ox). In general, was determined the crystal structure of 20 new hydrides (deuterides) and the distribution of hydrogen atoms in the metal lattice was determined. Selectively investigated their physics and physicochemical properties. On the basis of established dependences composition-structure-properties for the investigated hydrides, are proposed the compositions of new geters and hydrogen accumulators.