ELECTRODISSOLUTION KINETICS OF IRON IN CHLORIDE SOLUTIONS .8. CHAOS IN POTENTIAL CURRENT OSCILLATIONS

The electrodissolution of iron in aqueous NaCl solutions has been studied under a variety of conditions with rotating ring-disk electrodes. The current oscillations observed under potentiostatic conditions, as well as the potential oscillations observed under galvanostatic conditions, are all aperiodic. Detailed analysis, using numerical diagnostics developed to characterize complex time series, clearly shows that the irregularity in these time series corresponds to deterministic chaos, rather than to random noise. The estimation of the correlation dimension in systems where the underlying dynamics are deterministic, but in which experimental noise is also present, is accomplished by a new technique described here.