A PROTECTIVE-DECORATIVE CATHODIC CONVERSION COATING ON STEEL

A decorative conversion coating was formed on mild steel from a soluti on of sodium molybdate and phosphate by cathodic treatment. Anodic cor rosion curves demonstrated the good anticorrosive ability of the coati ng formed. The results of XPS analysis showed that iron existed as iro n (II) and iron (III) in the film; molybdenum existed as molybdenum (V I) in the surface layer of the film, while as molybdenum (VI) and moly bdenum (IV) in the inner layer of the film; phosphorus in the film was present in the pentavalent state. The relative atomic percent content (A.C.%) of the film was obtained by AES profile to be oxygen 58.6, mo lybdenum 21.3, phosphorus 10.2, iron 6.5 and carbon 3.4.