THE INVESTIGATION OF CERIUM AS A CATHODIC INHIBITOR FOR ALUMINUM-COPPER ALLOYS

In situ current density mapping, scanning electron microscopy, and ene rgy dispersive spectroscopy were used to study the effects of cerium a s a corrosion inhibitor for an aluminum copper alloy (Al 2024-T4) in c hloride containing solutions. It was found that cerium inhibits corros ion of this alloy by reducing the rate of the cathodic reaction. This was due to the formation of cerium-rich films over copper containing i ntermetallics which act as local cathodic sites. Results from tests ca rried out on an aluminum/copper galvanic couple, which was used to sim ulate the electrochemical behavior of the copper containing intermetal lics, showed that corrosion inhibition was associated with the formati on of a Ce-rich film over the copper in agreement with that observed f or the alloy.