Electrochemical noise generation during corrosion of stainless Steel-Type 316 in acid Chloride Environment.

The electrochemical noise generated during the pitting and general corrosion of austenitic stainless steel-Type 3.16 in acid chloride environment was studied under free corrosion potential and at ambient temperature. The electrochemical noise was observed as spontaneous fluctuation of potential. The observed corrosion behaviours as obtained from the results are related to the existing known pitting/general corrosion mechanism(s) of stain1ess steels. The clearest indication of results are given by the spectrum standard deviation (essentially the average noise power) the noise voltage density, and the roll-off slope parameters. All the noise amplitudes generally increase with decreasing frequency and the power spectral density is inversely proportional to some power of the frequency, thus indicating '1 /f' or 'flicker' noise. The SEM micrograph made from the plastic replicas of the surface of specimens, showed the occurrence 9f pitting and severe general corrosion.