Stefano Deledda

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Crystal structure determination is essential for characterizing materials and their properties, and can be facilitated by various tools and indicators. For instance, the Goldschmidt tolerance factor (T) for perovskite compounds is acknowledged for evaluating crystal structures in terms of the ionic packing. However, its applicability is limited to(More)
Magnesium borohydride (Mg(BH4)2) is one of the most promising complex hydrides presently studied for energy-related applications. Many of its properties depend on the stability of the BH4(-) anion. The BH4(-) stability was investigated with respect to H→D exchange. In situ Raman measurements on high-surface-area porous Mg(BH4 )2 in 0.3 MPa D2 have shown(More)
The effect of transition metal fluorides on the decomposition of NaBH4 has been investigated for NaBH4 ball milled with TiF3, MnF3 or FeF3. The compounds were examined by thermal programmed desorption with residual gas analysis, thermo gravimetric analysis and volumetric measurements using a Sieverts-type apparatus. The phase formation process during(More)
The possibilities to produce quaternary Mg-based transition-metal complex hydrides have been explored. Mg2Mn1--xFex (x = 0.5, 0) elemental powder mixtures were ball milled in a reactive D2 atmosphere (about 5 MPa). The results were compared with the formation of Mg2(FeD6)0.5(CoD5)0.5 from Mg-Fe-Co powders. The changes of D2 pressure were monitored during(More)
Among the thermodynamic properties of novel materials for solid-state hydrogen storage, the heat of formation/decomposition of hydrides is the most important parameter to evaluate the stability of the compound and its temperature and pressure of operation. In this work, the desorption and absorption behaviors of three different classes of hydrides are(More)
Mg2(Fe0.5Co0.5) elemental powder mixtures were processed by reactive ball milling in a H2 (orD2) atmosphere at about 50 bar. The changes of pressure were monitored during milling and hydrogen absorption was detected within the first 10 h of milling. X-ray and neutron powder diffraction analysis, followed by Rietveld refinement, suggests an almost complete(More)
Magnesium borohydride (Mg(BH4)2) is one of the most promising hydrogen storage materials. Its kinetics of hydrogen desorption, reversibility, and complex reaction pathways during decomposition and rehydrogenation, however, present a challenge, which has been often addressed by using transition metal compounds as additives. In this work the decomposition of(More)
Ball milling techniques have been used extensively in the last 30 years for the synthesis and processing of novel materials. The continuous fracturing and cold welding processes during milling allows to mechanically mix elements/compounds at an atomic scale, extend the solid solubility of metals and, in turn, obtain new alloys that might show interesting(More)
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