Corrosion resistance evaluation of Al‐based alloys by means of dynamic electrochemical impedance spectroscopy

Abstract

Purpose

The purpose of this paper is to present the investigation of aluminum alloy by means of dynamic electrochemical impedance spectroscopy (DEIS), which is simultaneous method of AC impedance and DC polarization measurements.

Design/methodology/approach

A method of DEIS has been applied. Changes in equivalent circuit (EC) parameters versus potential for both investigated aluminium alloys are evaluated.

Findings

On the basis of obtained results, it is unambiguously demonstrated that the addition of 4.5 percent magnesium degraded the anticorrosive properties of the test alloys. It is difficult to define unequivocally the range of passive state and a moment of passive layer breakdown on the basis of current/voltage dependencies. However, application of the DEIS method and analysis of the evolution of particular elements of an electrical EC allowed identification of the instant of corrosion process initiation.

Practical implications

The presented method is only suitable for laboratory evaluation of metal alloys because it requires sophisticated measuring equipment and is a difficult and time‐consuming way to obtain final results.

Originality/value

In one experiment, both polarization (DC) data and impedance (AC) measurements can be obtained. This allows the electrochemical properties of very similar aluminum alloys to be compared precisely with one other.

Citation

Krakowiak, S. and Darowicki, K. (2010), "Corrosion resistance evaluation of Al‐based alloys by means of dynamic electrochemical impedance spectroscopy", Anti-Corrosion Methods and Materials, Vol. 57 No. 1, pp. 28-32. https://doi.org/10.1108/00035591011009718