The potential and current oscillations during pitting corrosion of steel in NaCl solution were studied. Detailed analysis using numerical diagnostics developedto characterizecomplex time series clearly shows that the irregularity in these time series corresponds to deterministic chaos, rather than to random noise. The chaotic oscillations were
characterized by power spectral densities,phase space and Lyapunov exponents. Key words: electrochemicalnoise, chaos, pitting corrosioL steel.