Formation of nanoporous oxide by self-organized anodizing of FeAl intermetallic alloy in oxalic acid solution containing glycol

Nanoporous oxide was formed by self-organized two-step anodizing of FeAl intermetallic alloy in 0.3 M (COOH)2 with 20 vol% of glycol, what allowed to decrease ionic mobility and consequently decrease current density and oxide growth rate. Additionally, the voltage range for anodizing was extended up to 40 V, while compared to FeAl anodizing in sulfuric acid. Furthermore, morphology of the grown oxide can be controlled by the voltage: pore diameter and interpore distance increase linearly with the voltage, but slopes of the fitted lines are smaller than in the case of intermetallics anodizing in different electrolytes.