Wk. Choi et al., Electrochemical and structural characteristics of TiV2.1Ni0.3 surface-modified by ball-milling with MgNi, J ALLOY COM, 299(1-2), 2000, pp. 141-147
V-based TiV2.1Ni0.3 alloy with high hydrogen storage capacity was surface-m
odified by ball-milling with amorphous MgNi alloy prepared by mechanical al
loying. In charge-discharge cycle measurements, the decrease in discharge c
apacity for the prepared TiV2.1Ni0.3-MgNi composites was effectively suppre
ssed in comparison with the TiV2.1Ni0.3 alloy. In particular, ball-milling
for 3 h is the most effective in the present study. This was explained by s
urface analyses with EPMA mapping and X-ray photoelectron spectroscopy (XPS
). Changes in the EPMA maps, XPS spectra and depth profiles of the surface
alloy components suggested that the ball-milling caused the mutual diffusio
n between Mg and a little of the Ni components in the MgNi alloy and Ti and
V components in the TiV2.1Ni0.3 alloy at the interface between both alloys
. In addition, stable time course of rest potential for the TiV2.1Ni0.3-MgN
i composite electrodes immersed in 6 M KOH solution also showed the effecti
veness of the surface modification with ball-milling. (C) 2000 Elsevier Sci
ence S.A. All rights reserved.