HYDROGENATION BEHAVIOR OF THE NEW COMPOSITE STORAGE MATERIAL MG-X-PERCENT FETI

Mg-x wt.% FeTi composite alloys have been successfully synthesized. Th e hydrogenation behaviour of these alloys has been extensively studied . The materials have been activated at 400-degrees-C under a hydrogen pressure of approximately 30 kg cm-2 and their hydrogen storage capaci ties and kinetics have been evaluated. The new composite hydrogen stor age material in contrast to the native ingredient FeTi, has been found to possess much higher storage capacity and exhibits favourable absor ption-desorption kinetics. For Mg-40% FeTi, a storage capacity of appr oximately 3-3.6 wt.% at room temperature (almost-equal-to 27-degrees-C ) has been found. This is the highest known capacity exhibited by any hydrogen storage material at ambient conditions. In order to unravel t he hydrogenation behaviour of these materials, structural-microstructu ral characteristics, and chemical composition before and after hydroge nation through X-ray diffraction, scanning electron microscopy and ene rgy-dispersive analysis of X-rays have been carried out. The ambient c ondition hydrogenation properties of these composite alloys have been found to be strongly correlated with the structural and microstructura l characteristics. Based on the observed structural and microstructura l characteristics, the details of hydrogenation behaviour have been ou tlined in terms of cracking of FeTi matrix on hydrogenation and provis ion of continued fresh surfaces for hydrogenation of FeTi-Mg, Mg-TiMg eutectic mixtures or FeTi-Mg complexes. The present composite alloy co rresponds to a new hydrogen storage material with higher storage capac ity (almost-equal-to 3-3.6 wt.%) and suitable kinetics (initial hydrog enation in 10 min, saturation hydrogenation in 40 min).