Effect of Trace Indium on Corrosion Resistance of Rare-earth Aluminum Brass

The effect of trace indium on the corrosion resistance of rare-earth aluminum brass was studied by means of weight loss measurement, electrochemical testing, XRD and scanning electron microscopy. The results show that the average corrosion rate of the ceric aluminum brass was 7.3×10-3 mm/a, with the addition of trace indium, the polarization resistance was greatly improved and the free corrosion current density was reduced, the average corrosion rate was 6.7×10-3 mm/a. The trace In can improve the structure of the corrosion film and after corrosion in 3.5% NaCl solution, a tight and integrated corrosion film was formed on the surface of the matrix and the film can inhibit the diffusion of Zn atoms from the matrix to the solution to a certain extent. Besides, In can reduce the release of hydrogen from Zn, and thus can further inhibit the dezincification of brass.