Surface Treatment for Corrosion Resistant Aluminium Alloys by Removing Intermetallic Phases
It is well known that the Al-Fe system intermetallic compound particles on the aluminum and its alloys are detrimental to the corrosion for aluminum materials. Trial and error efforts reveal that Al3Fe intermetallic compound particles exposed on aluminum are preferentially and selectively removed by electrochemically treatment in cathodic current. These treatment combined by two steps: the first step is selective dissolution of aluminum component in the Al3Fe intermetallic compound by electrochemical reaction. The second step is intensive removal of the iron-enriched intermetallic particles on which vigorous hydrogen bubbling has been took place. The electrochemical measurement and surface observation show that the aluminum and its alloys with free intermetallic compound particles treated by aboves have excellent corrosion resistance in a NaCl solution. It is also found that the intermetallic compound-free surface is preferable for the pretreatment surface for the surface finishing.
W.J. Poole, M.A. Wells and D.J. Lloyd
O. Seri "Surface Treatment for Corrosion Resistant Aluminium Alloys by Removing Intermetallic Phases", Materials Science Forum, Vols. 519-521, pp. 729-734, 2006