ELECTROCHEMICAL BEHAVIOR OF CUPRONICKEL ELECTRODE IN ACIDIC MEDIA

Аннотация

The electrochemical properties of the cupronickel electrode polarized by an alternating current in an
aqueous solution of hydrochloric acid were studied for the first time. The electrochemical dissolution of cupronickel
was carried out in a polarization mode with a frequency of 50 Hz in pairs with a titanium electrode. The current
efficiency of dissolution of Cu-Ni alloys dependence on the current density at the titanium (20-120 kA/m2
) and
cupronickel (200-1200 A/m2
) electrodes, the concentration of a hydrochloric acid solution (0.5-5.0 M), the
electrolysis duration (0.5-1.75 h) and the alternating current effect (50-300 Hz) were considered. It was observed that
the current efficiency of the alloy dissolution decreases linearly with increasing current density at the cupronickel
electrode, while the current density at the titanium electrode passes through a maximum value at 60 kA/m2
. The
dependence of the alloy dissolution on the acid concentration was studied, and the reaction order was calculated. The
reaction orders for the formation of copper (I) and nickel (II) ions accounted for 0.95 and 0.85, respectively. As the
frequency of the alternating current increased, the current efficiency of the cupronickel electrode dissolution changed
significantly. It has been shown that high current frequencies do not provide the required anodic half-cycle duration
for the oxidation reaction of the metals, as the periods change very rapidly. It was found that electrolysis is effective
at a frequency of 50 Hz AC. It was observed that the dissolution rate of the copper-nickel alloy increases with
increasing solution temperature. It was found that the dissolution of cupronickel in an aqueous solution of
hydrochloric acid by the temperature-kinetic method takes place in the diffusion-kinetic mode. Ideally, the current
efficiency values were 59% for Cu (I) ions and 15% for Ni (II) ions