XPS study of adsorption of 2-mercaptobenzothiazole on a brass surface

The surface of brass (Cu80/Zn20) exposed in water and different aqueous solutions and 2-mercaptobenzothiazole (MBT) is studied by XPS. The leaching of zinc (dezincification) is observed in pure water and in borate solutions. On the contrary, if brass is exposed in 0.5 M NaCl or Na2SO4 solutions copper is removed from the surface layer leaving brass surface covered by oxidized zinc, thus “decuprification” occurs. Exposure of brass in 0.05 mmol/l MBT solution reduces results oxide growth and forms mix complex CuZnMBT layer, which thickness increases with time. Adding 0.5 M NaCl to this solution does not remove copper from the surface.