Application of X-Ray Computed Tomography to Assess the Effect of Elevated Temperature on Atmospheric Corrosion of Aluminum Alloy 6063 in Contact with FeCl3 Droplets

The atmospheric corrosion behavior of aluminum alloy 6063-T5 with exposure to FeCl3 containing droplet deposits to simulate direct contact with steel corrosion product droplets has been investigated. Experiments were performed at 50°C and compared to room temperature exposure conditions to assess the behavior of aluminum heatsink materials. The evolution of corrosion sites, penetration rates, and corrosion product chemistry was analyzed using x-ray computed tomography, Raman spectroscopy, and electron microscopy techniques. The measured corrosion rates were lower when the temperature was raised, even when exposed to multiple wet-dry periods. The lower corrosion rates were attributed to a reduced propensity to form iron oxyhydroxides/oxides at the aluminum surface, which were present after room temperature exposure. The results are discussed in light of the galvanic corrosion behavior of aluminum alloy in contact with liquid steel corrosion products.