The differences in the electrochemical behavior of a rapidly solidified, two-phase (matrix and dispersoid) microcrystalline Al-based alloy containing Fe, V, and Si (FVS0812 alloy), the bulk forms of its phases, and polycrystalline Al were investigated in neutral berate buffer solution. FVS0812 shows higher activity than the matrix and pure Al, while the dispersoid is the most active, due to oxygen evolution and dissolution, even in this benign solution. Barrier oxide films formed at FVS0812 appear to be generally uniform and similar in thickness to those formed at the matrix material. At low anodizing voltage the dispersoid phase appears to form an oxide film, although some loss of Fe and V is inferred. However, at higher voltages, evidence for the incomplete oxidation of the dispersoid phase and its incorporation and/or subsequent loss from some sites in the oxide film is seen, leading to a more flawed film of less uniform thickness. The higher capacitance of the oxide film at FVS0812 compared to that of films formed under identical conditions at Al and the matrix is consistent with the penetration of solution, via flaws, into the oxide film and the development of regions of thinner oxide film at dispersoid containing sites.