Effect of NaOH concentration on dissolution behavior for Al-Fe alloy

Dissolution behavior of Al-Fe alloy in 1, 3 and 5% NaOH solution at room temperature (about 25°C) has been investigated. Weight loss of the Al-Fe alloy etched by the NaOH solution linearly increases with increase in concentration of NaOH. The dissolution behavior has been qualitatively interpretated in terms of superimposement of anodic polarization curve of pure aluminum and cathodic polarization curve of intermetallic compound. The intermetallic compounds which are electrically conducted to the aluminum matrix play a cathodic role, and at the same time they dissolve themselves into the solution due to their small polarization resistance.