Aqueous corrosion of tin-bronze and inhibition by benzotriazole

The microstructure of Cu-11 wt% Sn bronze has a marked effect on the distribution of corrosion. Heterogeneous bronze exhibited a greater degree of selective attack in seawater than What Occurred on homogeneous alloys. Microprobe analysis and x-ray photoelectron spectroscopy studies showed that copper-rich areas dissolved preferentially in aerated seawater. Polarization work showed that benzotriazole is a good anodic inhibitor for bronze immersed in seawater and sodium chloride (NaCl) solution. The addition of 1 g/L benzotriazole to seawater significantly increased the time for the onset of visible corrosion on immersed bronze, while predipping had little effect. In aerated seawater containing benzotriazole, the copper was preferentially attacked; however, under wet mud in seawater, the tin showed slightly more dissolution.