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