J Mater Sci Technol ›› 1992, Vol. 8 ›› Issue (3): 192-196.

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Protective Characteristics and Formation Mechanism of the Corrosion Product Films of B30 Tubes Exposed to Seawater

ZHU Xiaolong LIN Leyun Surface Technology Center,General Research Institute for Nonferrous Metals,Beijing,110083,ChinaTo whom correspondence should be addressed   

  • Received:1992-05-28 Revised:1992-05-28 Online:1992-05-28 Published:2009-10-10

Abstract: The corrosion product films of two kinds of B30 tubes(similar to CDA 715)exposed to seawat- er for various periods of time were investigated by SEM,AES and XPS.The results show that the pro- tective corrosion product film is thin,uniform and adherent.FeOOH is found to be present in the film surface,which confirms the hypothesis that iron hydroxide segregates at the surface of the film.The FeOOH promotes Ni enrichment in the corrosion layer by preventing Ni from running off.The corro- sion product film with no protectiveness is of lay- ered structure,loose and bad adherence.The for- mer film is formed through direct oxidation and the latter by precipitation and redeposition from dis- solved species.

Key words: Cu-Ni alloy, corrosion product film, exposure