Hydrogen in Mechanically Prepared Ti-h-BN Systems
O. S. Morozova1, T. I. Khomenko1, A. V. Leonov2, Ch. Borchers3, E. Z. Kurmaev4 and A. Moewes5
1Semenov Institute of Chemical Physics, Russian Academy of Sciences,
Ul. Kosygina 4, Moscow 119991 (Russia)
E-mail: om@polymer.chph.ras.ru
2Lomonosov Moscow State University,
Leninskiye Gory, Moscow GSP-2, 119992 (Russia)
3Institute for Material Physics, University of Goettingen,
Friedrich-Hund-Platz 1, Goettingen D-37077 (Germany)
4Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences,
Ul. S. Kovalevskoy 18, Yekaterinburg GSP-170, 620219 (Russia)
5Department of Physics and Engineering Physics, University of Saskatchewan,
Saskatoon (Canada)
Страницы: 203-211
Аннотация
The effect of BN addition on hydrogen uptake by Ti after and during mechanochemical activation under flow conditions was studied using kinetic, structural, microscopic and spectroscopic techniques. An addition of hexagonal BN significantly stimulated Ti-H2 interaction during and after the milling process. The hydrogen uptake temperature (Tmax) decreased from 960 to 590 K after mechanical treatment of Ti with h-BN in helium flow due to formation of porous BN matrix containing randomly distributed Ti nanofragments. No titanium surface or bulk modification by N (B) atoms was found. Contrary to this, new types of occupation sites available for hydrogen in Ti lattice were formed under the milling in H2/He flow. These centres responsible for a drastic reduction of H2 desorption temperature from 1000 to 670-610 K were attributed to the presence of interstitial N atoms. Similar effect on hydrogen distribution between the site types was observed for TiH2/h-BN as-milled system.
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