Abstract
The characteristic features of the electrochemical behavior of the amorphous 
alloy in alkaline media have been investigated. Changes occurring in both the physical state and the composition of the surface layer during chemical etching and electrochemical activation were studied by scanning electron microscopy, Auger electron spectroscopy, x‐ray diffraction, and cyclic voltammetry. Several new anodic maxima were observed in cyclic voltammograms after long‐term cycling and were attributed to the oxidation of hydrogen atoms stored in low‐energy fourfold coordinated interstitial sites, 
and
. The kinetics of the hydrogen evolution reaction (HER) on the alloy under investigation was studied in terms of the cathodic polarization curves. The Tafel plots contain two different ranges: (i) a low‐overpotential range, in which the slope of the linear η vs. 
is characteristic for charge transfer controlled processes; (ii) a high‐overvoltage range, in which a combined mechanism, charge transfer and hydrogen diffusion into the bulk, is operative. To get information about the parameters influencing the hydrogen charging and discharging processes, chronopotentiometric experiments were performed. The changes of anodic overvoltage with time during constant current discharge were used to determine the electrochemical parameters 
and β, as well as the diffusion coefficients 
of the H atoms in the bulk of the alloy. Both
and 
increased with hydrogen concentration, an observation which is consistent with a broad distribution of interstitial sites in the amorphous alloy.