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An investigation of the effects of inorganic inhibitors on the corrosion rate of aluminum alloy using electrochemical noise measurements and electrochemical impedance spectroscopy

Mohammad Ghassem Mahjani (Chemistry Department, K.N. Toosi university of Technology, Tehran, Iran)
Mohammad Sabzali (Chemistry Department, K.N. Toosi university of Technology, Tehran, Iran)
Majid Jafarian (Chemistry Department, K.N. Toosi university of Technology, Tehran, Iran)
Jaber Neshati (Corrosion Department, Research Institute of Petroleum Industry, Tehran, Iran)

Anti-Corrosion Methods and Materials

ISSN: 0003-5599

Article publication date: 27 June 2008

Abstract

Purpose

The purpose of this paper is to investigate the effects of inorganic inhibitors on the corrosion rate of aluminum alloy using the electrochemical noise (EN) analysis and electrochemical impedance spectroscopy (EIS) techniques.

Design/methodology/approach

EN and EIS measurements were employed to study the corrosion behavior of aluminum alloy in Na2SO4(0.50 M)/NaCl(0.20 M) solution in presence of inorganic inhibitors. The time‐series noise patterns were transformed into the frequency domain using fast Fourier transformation, and then their power spectrum densities (PSDs) at specified frequencies were determined and compared with the EIS and polarization results.

Findings

The EN, EIS and polarization results were in agreement. The inhibitive effect of the anions decreased in the order: CrO42−>Cr2O72−>NO3>WO42−>MoO42−>NO2. The results showed that the slope of PSD of the current (i.e. the “roll off”) was less where inhibition efficiency was greater. The spectral noise impedance and the modulus of the impedance recorded using impedance spectroscopy showed good agreement.

Originality/value

This paper provides useful information relative to corrosion inhibition efficiency of the sodium and potassium salts using EN analysis technique.

Keywords

Citation

Ghassem Mahjani, M., Sabzali, M., Jafarian, M. and Neshati, J. (2008), "An investigation of the effects of inorganic inhibitors on the corrosion rate of aluminum alloy using electrochemical noise measurements and electrochemical impedance spectroscopy", Anti-Corrosion Methods and Materials, Vol. 55 No. 4, pp. 208-216. https://doi.org/10.1108/00035590810887718

Publisher

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Emerald Group Publishing Limited

Copyright © 2008, Emerald Group Publishing Limited