On the synthesis and hydrogenation behaviour of MmNi5-xFex alloys and computer simulation of their P-C-T curves

The present paper deals with the synthesis of MmNi(5-x)Fe(x) alloys (x = 0.05, 0.1, 0.3, 0.5). It has been found that Fe substitution, because of the higher electron attractive power of the Fe when substituted, leads to enhancement of the hydrogen storage capacity. Thus, the material MmNi(4.9)Fe(0.1) shows a storage capacity of similar to1.66 wt.%, which is one of the highest capacities for any as synthesised AB(5) type alloy. The P-C isotherms at various temperatures have been simulated by a suitable mathematical model. For this, the randomised variables DeltaH and DeltaS have been evaluated experimentally. These have been used as input parameters in the modelling. The simulated and experimental curves have been found to match closely. It is suggested that mathematical modelling is useful for predicting P-C-T behaviours when the hydride is used at different temperatures. (C) 2003 Elsevier B.V. All rights reserved.