Correlation between the corrosion rate and electrochemical noise energy of copper in chloride electrolyte.

Benfeng Zhu,Zhao Zhang,Yumeng Yang,Xiaoqing Du,Chenxi Yi

doi:10.1039/c8ra01203b

Abstract

An electrochemical noise technique has been applied to describe the corrosion process of copper. The results show that the sampling frequency clearly changes both the energy distribution plot and the power spectral density spectra, which should be taken into consideration strictly and logically before an electrochemical noise test. The corrosion energy, (Ec), deduced using the fast wavelet transform method showed a similar variation trend with corrosion rate. Hence, the proposed parameter Ec represents the corrosion rate or severity.

Highlights

The results show that the sampling frequency clearly changes both the energy distribution plot and the power spectral density spectra, which should be taken into consideration strictly and logically before an electrochemical noise test
9–11 the uctuation of electrode potential always simultaneously consists of “slow DC dri ” and a “fast random non-equilibrium uctuation signal”. The former is the traditional electrode potential, which indicates the thermodynamic stability; whilst the latter is designated as electrochemical noise, which represents the speed of the electrode reaction
For 0.06 M, 0.09 M and 0.12 M NaCl, the RP-EDPs remain the same and the maximum energy is in D1–D3 when f $ 8 Hz while it is in D7–D8 when f < 4 Hz

Summary

Introduction

Electrochemical noise (EN) is the generic term given to the uctuation of current and potential, and corrosion engineering is regarded as one of its important elds of application.[1,2,3,4,5,6] Fluctuations of electrode potential are connected to local anodic and cathodic reactions and are a consequence of events occurring at aws (such as pitting nucleation, propagation, and re-passivation), which are strictly related to the corrosion process.[7]From a physicochemical viewpoint, the electrode potential is de ned as the change in Gibbs energy when a charged particle transfers from the in nite into an electrode, including both the electrical and chemical work done during the process, whereas, potential only consists of the electrical work in the above transfer process. Correlation between the corrosion rate and electrochemical noise energy of copper in chloride electrolyte

Results

Conclusion