Effect of Applied Potential on the Fretting Corrosion Behavior of 6082 Aluminum Alloy in 3.5% NaCl Solution

The fretting corrosion behavior of 6082 aluminum alloy in 3.5% NaCl solution under natural and applied potential polarization conditions was studied by using a high-precision multi-functional fretting-corrosion apparatus. Its fretting behavior, wear mechanism, corrosion behavior and the effect of the applied potential were analyzed in detail by scanning electron microscope and X-ray photoelectron spectroscopy. The results indicated that under the anodic potential polarization, the surface of the material was more prone to slip, so the range of gross slip zone was expanded, mixed zone and partial slip zone were narrowed. Friction coefficient decreased firstly and reached the minimum value at the self-corrosion potential. And then friction coefficient raised with the increasing potential. The friction coefficient at the cathode potential was larger than that at the anode potential. Under cathodic and self-corrosion potential polarization, the corrosion of the wear region was accelerated by the fretting behavior, which increased the corrosion current. While under the anodic polarization, the corrosion of the wear region and corrosion current was reduced by the fretting behavior. The damage degree of the material increased with the positive shift of the applied potential. Under cathodic and self-corrosion potential polarization, the wear mechanism of 6082 aluminum alloy was mainly delamination wear and mild abrasive wear, while under anodic potential polarization, that was mainly abrasive wear and corrosive wear.