The Role of H₂O₂ and K₂S₂O₈ as Oxidizing Agents for Accelerated Corrosion Testing

In this work, the application of hydrogen peroxide (H₂O₂) and potassium persulfate (K₂S₂O₈) in accelerated corrosion testing was considered. H₂O₂ is already used as an accelerant in the standard immersion test ASTM G110, and K₂S₂O₈ is an oxidizing agent that shows promise for corrosion testing applications. A Koutecky-Levich approach was used to investigate the cathodic kinetics of both oxidizing agents as well as dissolved oxygen (O₂). Cathodic kinetics for O₂, H₂O₂, and S₂O₈²⁻ were faster when measured on a platinum electrode than when measured on an AA2060-T3 electrode. This difference was attributed to the additional limit to cathodic kinetics posed by the protective oxide film on aluminum. H₂O₂ was a more potent accelerant than K₂S₂O₈ at a concentration of 0.1 M due to the faster cathodic kinetics of H₂O₂ on aluminum. However, K₂S₂O₈ was more convenient to use in a laboratory setting due to its stability during storage. The severity of tests using K₂S₂O₈ was increased by lowering the solution pH to 2.28. At the low solution pH, cathodic kinetics and extent of attack increased.