Boron Enhanced Synthesis of Ti-hydride Nanoparticles by Milling Ti/B in Hydrogen Flow

C.      Borchers; T.      I. Khomenko; A.      V. Leonov; O.      S. Morozova; J.      Cizek; I.      Prochazka; A.      S. Shkvarin; E.      Z. Kurmaev; A.      Moewes

doi:10.2174/157341311797483817

Abstract

Morphological, structural and chemical evolution in Ti/B/H2 system is studied in detail as a function of mechanical treatment. Ti/B powder continuously changes both in composition and morphology during ball-milling in H2 flow: The powder composition varies from Ti/B to TiH2-x/B causing a change in mechanical properties. The role of boron additive also changes from preventing the Ti nanoparticles from sticking together in the early stages to a matrix material participating in Ti – B interface reactions in the intermediate and final stages of the process. Boron atoms participating in the formation of nanoscopic holes give rise to new H states in the hydride by changing the local atomic state of Ti atoms. The dynamics of the formation of these sites and the redistribution of hydrogen between different types of occupation sites in dependence of phase composition and milling time of the powders are also studied.

Keywords: mechanochemical synthesis, nanoparticles, nanoscopic holes, titanium hydride, hydrogen sorption, hydrogen desorption, hydrogen storage, positronium, positron annihilation spectroscopy, X-ray emission spectroscopy, transmission electron microscopy, thermal desorption spectroscopy