Effect of Alloying Elements in Melt Spun Mg Alloys for Hydrogen Storage

S. ROZENBERG; F. AUDEBERT; J. LANG; F. SAPORITI; P. BOTTA; M. STOICA; J. HUOT; J. ECKERT

Cancún

Simposio; NANOMAT 2015; 2015

NANOMAT & TMS

Mg has high technological interest due to its potential application for hydrogen storage. Mg has high hydrogen absorption capacity of 7.6 wt% H, but in order to expand its application is still needed to decrease the absorption-desorption temperature and improve the kinetics reactions. Therefore, it is of interest to study the effect of the addition of a series of alloying elements on the hydrogen absorption-desorption behaviour. Samples have been produced by rapid solidification by means of melt spinning technique in order to obtain a refined microstructure and a good surface/volume ratio. The effect of Cu and Si were studied in the Mg90Si10, Mg90Cu10, Mg65Cu35 (at%) alloys, and the effect of the rare earths (using MM: mischmetal solid solution) and Al were studied in the Mg65Cu25Al10, Mg65Cu25MM10 and Mg65Cu10Al15MM10 (at%) alloys. The samples morphology was observed by scanning electron microscopy and the microstructure were characterized by X-ray diffraction. The stability and the crystallisation process in the Mg-Cu-MM based alloys were studied by means of differential scanning calorimetry (DSC). The hydrogen absorption-desorption cycles were performed at 350°C.All the melt-spun alloys without MM show a crystalline structure, and the Mg65Cu25MM10 and Mg65Cu10Al15MM10 alloys showed an amorphous and partially amorphous structure respectively. At 350˚C the MM containing alloys are fully crystallised, thus all the alloys had a crystalline structure during the hydrogen absorption-desorption tests.It was observed that Si and Cu in the binaries alloys studied hindered completely the activation of the Hydrogen absorption at 350˚C. The partial substitution of Cu by MM or Al allowed the activation of the Hydrogen absorption, and the combined substitution of Cu by MM and Al showed the best results with the fastest absorption and desorption kinetic at 350˚C.These results show that combination of Al and MM as alloying elements can be used as design strategy for new Mg alloys to be used as storage and continuous supply of hydrogen in energy systems, such as fuel cells.