Studies of hydrogen dynamics and structural aspects of polymer dispersed and boron added MmNi<inf>3.5</inf>Al<inf>0.5</inf>Fe<inf>0.5</inf>Co <inf>0.5</inf>

Pressure-composition (P-C) hydrogen absorption isotherms have been obtained for MmNi3.5Al0.5Fe0.5Co0.5+0.5 wt% B and MmNi3.5Al0.5Fe0.5Co0.5 +25 wt% polyaniline (PANI) in the ranges 30-100 °C and 0.1-40 bar using a high pressure Seiverts' apparatus. The phase structure and microstructure morphologies of as-prepared and ball-milled materials have been analysed by XRD and SEM respectively. The effect of particle size, boron addition and PANI dispersion on the hydrogen absorption kinetics in MmNi3.5Al 0.5Fe0.5Co0.5 has been studied and discussed. The diffusion coefficient and activation energy of dissolved hydrogen in MmNi3.5Al0.5Fe0.5Co0.5, MmNi 3.5Al0.5Fe0.5Co0.5+0.5 wt% B and MmNi3.5Al0.5Fe0.5Co0.5+25 wt% PANI have been obtained from the studies of hydrogen absorption kinetics using the first order rate equation and the results have been discussed. © 2005 IOP Publishing Ltd.