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Screening of new corrosion inhibitors via electrochemical noise analysis
Author(s) -
Slavcheva E.,
Schmitt G.
Publication year - 2002
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/1521-4176(200209)53:9<647::aid-maco647>3.0.co;2-l
Subject(s) - electrochemical noise , corrosion , electrochemistry , electrode , chemistry , ethylene glycol , corrosion inhibitor , materials science , analytical chemistry (journal) , metallurgy , chromatography , organic chemistry
The inhibition efficiency of a series of organic compounds against corrosion of magnesium alloy AZ91 in a 50 wt.‐% aqueous solutions of ethylene glycol has been studied using polarisation curves and electrochemical noise (ECN) measurements. The comparative analysis of the results obtained has demonstrated unambiguously that the method of ECN is an effective tool for screening of new corrosion inhibitors which offers some advantages comparing to the common electrochemical techniques. The very fast measuring rate enables to instantaneously register and monitor the rate of the corrosion process and changes in its mechanism in presence of the organic additives. The measurements are performed at freely corroding “identical” electrodes without perturbation from the external signals, which could lead (as in the polarisation measurements), to changes in the surface structure, the adsorption of the inhibitor etc. The statistical analysis of the noise data (in terms of standard deviations) in the time domain shows that the noise intensity of the system correlates well with the intensity of the corrosion process. The total amount of the charges exchanged during the tests is a quantitative measure for the inhibiting effect of the substances under study, while the spectral analysis of the noise in the frequency domain can be used to characterise the type of the corrosion attack.