Effect of Rare Earths addition on Al-Si hypoeutectic alloys: mechanical and corrosion behaviour

The lanthanides, for their chemical characteristics and chemical-physical properties, present themselves as strong candidates in the search for new corrosion inhibitors. These elements have often been used in aqueous solution in contact with Al-based materials in order to promote, after immersion, the formation of a surface passivation layer composed by their insoluble oxides and hydroxides, as an alternative method to chromating process. In this work, we will try to assess whether this positive effect is present even if these elements are directly added to the matrix during the alloy production. For this purpose it will carried out potentiodynamic polarization curves, using as corrosive environment a solution of NaCl 3.5% (w/w), at T = 25 ° C, P = 1 atm and in unstirred conditions, after an immersion time of 2 hours and using an electrochemical cell with three electrodes