Changes of Structural and Hydrogen Desorption Properties of Mgh2 Induced By Ion Irradiation

Abstract

Changes in structural and hydrogen desorption properties of MgH2 induced by ion irradiation have been investigated. Powder samples of MgH2 have been irradiated with 45 keV B3+ and 120 keV Ar8+, with ion fluence of 10(15) ions/cm(2). The effects of ion irradiation are estimated by Monte Carlo numerical calculations using the Stoping and Range of Ions in Matter (SRIM) package. The induced material modifications and their consequences on hydrogen dynamics in the system are investigated by XRD, particle size distribution and TPD techniques. Changes of TPD spectra with irradiation conditions suggest that there are several mechanisms involved in desorption process which depend on defect concentration and their interaction and ordering. The results confirmed that the near-surface area of MgH2 and formation of a substoichiometric MgHx (x LT 2) play a crucial role in hydrogen kinetics and that various concentrations of induced defects substantially influence H diffusion and desorption kinetics in MgH2. The results also confirm that there is possibility to control the thermodynamic parameters by controlling vacancies concentration in the system.