Tribochemical Decomposition of Light Ionic Hydrides at Room Temperature

Tribochemical decomposition of magnesium hydride (MgH2) induced by deformation at room temperature was studied on a micrometric scale, in situ and in real time. During deformation, a near-full depletion of hydrogen in the micrometric affected zone is observed through an instantaneous (t < 1 s) and huge release of hydrogen (3–50 nmol/s). H release is related to a nonthermal decomposition process. After deformation, the remaining hydride is thermally decomposed at room temperature, exhibiting a much slower rate than during deformation. Confocal-microRaman spectroscopy of the mechanically affected zone was used to characterize the decomposition products. Decomposition was enhanced through the formation of the distorted structure of MgH2 with reduced crystal size by mechanical deformation.We acknowledge financial support from the Ministry of Economy and Competitiveness of Spain through the grants RYC-2009-0412, BIA-2011-25653, and IPT-2012-1167-120000 with participation of the European Regional Development Fund (FEDER) as well as MINECO 2011-22780 and MAT2013-48009-C4-1-P