Oxide film formation on an al-cu alloy using spark anodisation methods
Date
2007
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Abstract
Enhanced corrosion resistance of the Al alloy AA2219 (6 wt. % Cu) can be achieved by normal anodisation in sulfuric acid. Unfortunately, a fatigue strength loss of ~ 40% results, due to the dissolution of Cu-rich constituents in the alloy. As an alternative, an AC/DC spark anodisation process using an alkaline silicate bath has been developed. The formed anodic oxide films were characterised using scanning electron microscopy (SEM), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The most passivating oxide films were obtained when the anodising bath contained 10 g/L of KOH and 40 g/L of a commercial sodium silicate solution and when the voltage reached 320:64 VDC:VAC. Atomic absorption spectrophotometry (AAS) and SEM suggested that many of the Cu-rich constituents in AA2219 remain intact after spark anodisation and the fatigue strength loss was found to be only ~ 12%. The corrosion resistance of anodised AA2219 could also be significantly improved with a polymer (Pary1ene HT) top-coat.
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Bibliography: p. 159-163
Some pages are in colour.
Some pages are in colour.
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McLeod, E. J. (2007). Oxide film formation on an al-cu alloy using spark anodisation methods (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/1412