Corrosion Behavior of Aluminum in Dilute Acetic Acid Solution Simulating Cooling Water in HVDC Transmission

The concentration, temperature effect and thermodynamic activation energy of aluminum corrosion in dilute acetic acid solution were explored by the polarization curve and the electrochemical impedance spectroscopy. With the increase of concentration and solution temperature of acetic acid solution, the corrosion resistance and charge transfer impedance of aluminum decreased. From 0 mM to 1.00 mM of acetic acid solution concentration, the corrosion potential, corrosion current density, anodic Tafel slope and charge transfer impedance of aluminum corrosion at 25 °C changed from -1.316 V, 0.207 μA cm-2, 5.581 V dec-1, 10.890 kΩ cm-2 to -1.141 V, 0.525 μA cm-2, 4.264 V dec-1, 7.344 kΩ cm-2. And with the solution temperature increase from 25 °C to 55 °C, the corrosion potential, corrosion current, anodic Tafel slope and charge transfer impedance of aluminum in 0.1 mM acetic acid solution changed from -1.248 V, 0.337 μA cm-2, 5.387 V dec-1, 9.590 kΩ cm-2 to -1.046 V, 1.651 μA cm-2, 5.031 V dec-1, 1.633 kΩ cm-2. The aluminum corrosion in dilute acetic acid solution was a transition chemical reaction of four processes (diffusion → surface adsorption → surface reaction → desorption).