SYNTHESIS OF HIGHLY ACTIVE Mg-BASED HYDRIDES USING HYDRIDING COMBUSTION SYNTHESIS AND NbF₅ ADDITIVES

Superiority of the hydriding combustion (HC) technique over conventional metallurgical approach to the synthesis of cost-effective Mg based hydrides, which show promise as hydrogen storage materials, is well known. In the present research, we report further improvements in HC prepared Mg -based materials, achieved by optimizing the preparative parameters of HC and by catalytic addition. Mg₉₀-Ni₆₀-C₄₀ composites prepared using optimized processing parameters were ball-milled with NbF₅ (10 h) and characterized for their micro-structural and hydriding properties. The ball-milled/catalyzed powder showed decreased crystallinity with CNTs on its surfaces. Surface area of the ball-milled powder decreased to almost half of the as-HC powder, while TG analysis revealed a four-fold decrease in the desorption temperature of the milled powder compared to that of the as-HC prepared powder. Activated samples achieved the maximum absorption/desorption limits (5.3 wt.%) at as low as 100°C, underlining the possibility of the use of these materials in portable hydrogen storage devices.