Comparison of Tafel Extrapolation and Linear Polarization Resistance Readings for TRC 8006 Aluminium Alloys in 3.5 wt.% NaCI Aqueous Solution

Abstract

Corrosion behaviour of the twin-roll casting (TRC) 8006 Al alloys has been investigated as a function of foil thickness by two different polarization techniques; Tafel extrapolation and linear polarization resistance. Polarization curve changes depending on foil thickness for the TRC 8006 Al alloys have been achieved using both the polarization techniques, respectively. The measurements were performed using a three-electrode electrochemical cell system. Tafel slopes, polarization resistance, density of corrosion current, corrosion potential and corrosion rate values have been calculated based on the data collected from both method’s outcomes and compared with those of each techniques used. For these two polarization curves, the corrosion rate values obtained for TRC 8006 Al alloy with a thickness of 180 µm is remarkably lower than the obtained results of TRC 8006 Al alloy with a thickness of 150 µm. This specifies that a decrease in foil thickness of the TRC 8006 Al alloys increased corrosion rate of the TRC 8006 Al alloys and thus the two techniques used in the present study to determine corrosion rate appears to be reliable methods for a long-term corrosion behaviour.