Effects of mechanical milling on desorption kinetics and phase transformation of LiNH2/MgH2 mixture

We have investigated the ball-milling (5–45 h) followed by dehydrogenation kinetics of LiNH2–MgH2 mixture. A new result of ball-milling reveals the formation of Mg(NH2)2 for mixtures ball-milled for more than 15 h. The desorption kinetics has been found to improve appreciably by increasing the duration of milling from 5 to 45 h. This enhancement is attributed to formation of Mg(NH2)2 during this process. It was found that the Mg(NH2)2 form through the reaction 2LiNH2 + MgH2 → Mg(NH2)2 + 2LiH. The phase and microstructural characterizations have been done through X-ray diffraction, IR-spectrometry, transmission and scanning electron microscopy. Correlation between particle size and hydrogenation behavior has also been investigated.