Oxidation of copper alloys in ambient air has been studied by the use of ESCA techniques. Alpha-brass oxidation begins with the formation of a relatively thick layer of zinc oxide followed by the growth of Cu(OH)_{2 and C}<sub_O _{on top of} _C<sub_<i2O. Contrary to the generally accepted process, dezincification in sea water begins with the outward migration and oxidation of large amounts of zinc. This process is followed by dissolution of some of the copper oxide layers and eventual cessation of zinc migration to the outside. Eventually islands of ZnO appear. -- AATA