A Study on the Electrochemical Impregnation Process in the Manufacturing of Cadmium Electrode

摘要

The electrochemical reactions, involved in the electro-chemical impregnation process for the fabrication of the cadmium electrode, contain a very complicated sequence of reactions. In this work, the electrochemical impregnation process was examined both experimentally and theoretically. Experimentally, two sets of potentiostatic transients were obtained for a nickel microelectrode in two different electrolytes. The first set of data was obtained in an electrolyte which contained no cadmium ion; the second set of data was obtained in an electrolyte which contained cadmium ions. The higher current density obtained in the second data set was due to the occurrence of the co-precipitation reaction between cadmium ions and hydroxy ions which were generated by the electrochemical reaction. Two models, which described the transport process and reactions under two different experimental conditions were developed. The model for a cadmium-ion-free electrolyte was used to identify the rate of the heterogeneous electrode reaction by matching the model prediction with the experimental results. The heterogeneous reaction rate constants so obtained were then used to identify the rate of the homogeneous precipitation reaction by again matching its model prediction with the experimental results. (Author)