Corrosion of LY12 aluminum alloy in sodium chloride solution

The corrosion behavior of LY12 alloy in sodium chloride solution and its electrochemical noise were reported. The development of the micro pits on the alloy surface was monitored by scanning electron microscopy, scanning tunneling microscopy, and electrochemical noise method. All the measurements show that the corrosion of LY12 alloy can be divided into two stages: a very reactive initial stage and a relative constant stable stage. The initial stage is corresponded to the adsorption of Cl ions and its reaction with the oxide film and the dissolution of Mg containing particles. The stable stage is corresponded to the development of the micro pits by the galvanic attack formed by Al Fe Cu Mn containing particles and the matrix. The initial stage lasts about 23 h while the stable stage dominates the whole corrosion process.