Magnesium mechanical alloys for hydrogen storage

Effect of the nature of the starting materials on the formation of Mg2FeH6

“…Previously Mg 2 FeH 6 has been obtained by sintering Mg and Fe powders at high H 2 pressures (∼100 bar) and temperatures of the order of 500 • C for several days [1,2]. An improvement in the synthesis of Mg 2 FeH 6 was made when mechanical alloying (MA) was used to obtain the hydride [3][4][5][6][7].…”

Effect of Nb2O5 on MgH2 properties during mechanical milling

“…Several routes to improve the H-sorption properties of magnesium have been explored: (a) alloying magnesium with transition metals, for example, Ni [5][6][7][8] or intermetallic compounds such as LaNi 5 and FeTi, to reduce the thermodynamic stability of magnesium [9][10][11][12][13], (b) alloying magnesium with transition metals such as Ti, Fe, Co, Zr, Nb, V and Pd to improve kinetics of the absorption or desorption of hydrogen [5,[14][15][16][17][18] and (c) chemical synthesising nanoparticles of magnesium doped with Ni [19]. These attempts resulted in improved MgH 2 H-sorption kinetics, however the dehydriding temperature was not below 330 • C and sometimes there was a dramatic loss of capacity.…”

Catalytic Action of Ammonia on the Mechanochemical Synthesis of Intermetallic Hydrides at High Gas Pressure

“…They also exhibit catalytic activities in reactions involving hydrogen, as has been reported in numerous publications [1][2][3][4][5][6]. Until the mid-1980s, two methods for the preparation of intermetallic hydrides were known, namely, by hydrogenation of alloys obtained by the pyrometallurgical process [1][2][3] and via organomagnesium compounds [4].…”

“…The drawbacks of the latter method are related to the poor practicability of processes involving organometallic compounds in industry. The hydride preparation method using so-called mechanical alloys obtained by mechanochemical activation of a mixture of two metals is free from these drawbacks [5]. These systems are readily hydrogenated without additional treatment and have a rather extensive specific surface area, and the energy expenditure for mechanical activation is much lower than in the pyrometallurgical method.…”