The electrochemical behaviors of AA8090 and the SiC particulate-reinforced equivalent MMC in deaerated 3.5% NaCl(aq) solution were investigated and compared in the pH range 2 to 12 and in the temperature range 10°C to 90°C. The effect of stirring of the solution on both materials was also studied, In the pH range investigated, the MMC was found to be only slightly more susceptible to pitting in terms of the values of the pitting potential and the protection potential. At lower temperatures, the passive current density was smaller for the MMC, while above 50°C, the values for the passive current density of both the matrix alloy and the MMC were nearly the same. In deaerated solutions, the effect of stirring was not marked, but when the solution was open to air, stirring drastically altered the shape of the polarization curve.
Kevwords: aluminium-lithiurn alloy, SiC particulate-reinforced metal matrix composite, pitting corrosion, stirring effect