Effect of electrolyte temperature on the polarization characteristics of an Al-Li-Cu-Mg alloy in NaOH

The effect of electrolyte temperature on the polarization characteristics of an Al-Li alloy of composition Al-1.90 Li-1.80 Cu-1.00Mg-0.09 Zr in 0.1 M NaOH solution was studied by the potentiodynamic polarization method. The electrolyte temperature was the equilibrium temperature established due to the prevailing weather conditions at different times in the year. The alloys exhibited active-passive behaviour at all the temperatures It was found that the temperature of electrolyte affected the polarization behaviour of the alloys. The zero current potential and the open circuit potential were nobler with decreasing temperature. The corrosion current density, critical current density and passive current density increased with temperature, indicating the activated nature of the electrochemical process. The passive range was higher at 35 degrees C compared to other temperatures. The temperature effect on polarization behaviour has also been explained by considering the dissolved oxygen concentration in the electrolyte at different temperatures. The ennoblement of Cu on the AI-Li alloy surface has also been addressed.