Multifractal Detrended Analysis of the Corrosion Potential Fluctuations During Copper Patina formation on Its First Stages in Sea Water

摘要

The analysis of multifractal time series (MFDFA) has been carried out for copper patina corrosionpotential Ecorr fluctuations in the period of 10 days, when flat samples were immersed in Caribbean seawater. The results showed that there are ranges of s-sizes for potential signals and -order fluctuations,where exhibits a power law behavior. The Hurst exponent h(q) values, the nonlinear multifractalspectrum 蟿(q) and the shape of the singularity spectrum f() confirmed that Ecorr series of copperexposed in sea water are compatible with a multifractal behavior. The tendencies of Ecorr change werecorrelated with the copper ions release (runoff) during dissolution of corrosion products in sea waterand with the significant transformation in the copper patina (Cu2O) composition as time of corrosionprocess advanced.