Rescaled range analysis of the corrosion potential noise

Abstract

Rescaled range ( R/ S) analysis of random events is known to reveal the persistent or antipersistent nature of the process. Time records of corrosion potential noise, i.e. spontaneous voltage fluctuations with zero current, were collected from freely corroding pure aluminium samples in a number of different electrolytes. The results of the R/ S analysis, also compared with those of simulated time series, revealed long term correlations, the nature of which were seen to be characteristic to the corrosion processes. The differences between the R/ S patterns of general and pitting corrosion have been found to be particularly distinctive.