Metallurgical and Materials Transactions B

, Volume 2, Issue 11, pp 3129–3134 | Cite as

The role of cupric complex ions in the dissolution and stress-corrosion cracking of α-brass in nontarnishing aqueous ammonia

  • E. N. Pugh
  • J. A. S. Green
Environmental Interactions


A study has been made of the dissolution and stress-corrosion cracking of copper and a series of α-brasses in nontarnishing 15 N ammoniacal solutions containing various concentrations of cupric complex ions. Corrosion studies under open-circuit conditions indicated that the dissolution process is controlled by the cathodic reduction of the cupric complexes or, more specifically, by the transport of these ions to the metal surface. Stress-corrosion tests confirmed earlier reports that failure of Cu-30 Zn under open-circuit conditions requires the presence in solution of cupric complexes in excess of a critical concentration. However, potentiostatic experiments demonstrated that cracking occurs in theabsence of significant cupric complex-ion concentrations provided that the dissolution rate of the specimens exceeds a critical value. Thus it is concluded that in stress-corrosion tests under open-circuit conditions the role of the cupric complex ions is simply to provide an efficient cathodic reaction, permitting rapid anodic dissolution. These observations are discussed in terms of the mechanism of cracking in these solutions.


Cupric Complex 


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  1. 1.
    E. Mattson:Electrochim. Acta. 1961, vol. 3, pp. 270–91.CrossRefGoogle Scholar
  2. 2.
    T. P. Hoar and C. J. L. Booker:Corrosion Sci., 1965, vol. 5, pp. 821–40.CrossRefGoogle Scholar
  3. 3.
    W. Lynes:Corrosion, 1965, vol. 21, pp. 125–31.Google Scholar
  4. 4.
    E. N. Pugh and A. R. C. Westwood:Phil. Mag., 1966, vol. 13, pp. 167–83.CrossRefGoogle Scholar
  5. 5.
    E. N. Pugh, J. V. Craig, and A. J. Sedriks:Proc. Conf. on Fundamental Aspects of Stress-Corrosion Cracking, pp. 118–51, NACE, 1969.Google Scholar
  6. 6.
    A. J. Forty and P. Humble:Phil. Mag., 1963, vol. 8, pp. 247–64.CrossRefGoogle Scholar
  7. 7.
    A. J. McEvily, Jr., and A. P. Bond:J. Electrochem. Soc., 1965, vol. 112, pp. 131–38.CrossRefGoogle Scholar
  8. 8.
    E. N. Pugh, J. V. Craig, and W. G. Montague:ASM Trans. Quart., 1968, vol. 61, pp. 468–73.Google Scholar
  9. 9.
    A. Howie and P. R. Swann:Phil. Mag., 1961, vol. 6, pp. 1215–26.CrossRefGoogle Scholar
  10. 10.
    E. N. Pugh, W. G. Montague, and A. R. C. Westwood:Corrosion Sci., 1966, vol. 6, pp. 345–46.CrossRefGoogle Scholar
  11. 11.
    D. H. Thompson and A. W. Tracy:Trans. AIME 1949, vol. 185 pp. 100–09.Google Scholar
  12. 12.
    G. Edmunds,Symp. on Stress-Corrosion Cracking of Metals, pp. 67–89,ASTM-AIME, 1945.Google Scholar
  13. 13.
    H. H. Uhlig and D. J. Duquette:Corrosion Sci., 1969, vol. 9, pp. 557–60.CrossRefGoogle Scholar
  14. 14.
    U. Bertocci:Electrochim. Metall., 1968, vol. 3, pp. 275–80.Google Scholar
  15. 15.
    M. G. Fontana and N. D. Greene:Corrosion Engineering, p. 311, McGraw-Hill, 1967.Google Scholar
  16. 16.
    F. A. Cotton and G. Wilkinson:Advanced Inorganic Chemistry, Interscience, 1962.Google Scholar
  17. 17.
    E. N. Pugh, W. G. Montague, and A. R. C. Westwood:ASM Trans. Quart., 1965, vol. 58, pp. 665–71.Google Scholar
  18. 18.
    S. W. Benson:The Foundations of Chemical Kinetics, p. 499, McGraw-Hill, 1960.Google Scholar
  19. 19.
    S. B. Chakrabortty: Metallurgy Program, Georgia Institute of Technology, private communication, 1970.Google Scholar
  20. 20.
    D. Tromans and J. Nutting:Corrosion 1965, vol. 21, pp. 143–60.Google Scholar
  21. 21.
    E. N. Pugh and A. J. Forty:Fundamental Aspects of Stress-Corrosion Cracking, p. 117, NACE, 1969.Google Scholar
  22. 22.
    H. E. Johnson and J. Leja:Corrosion, 1966, vol. 22, pp. 178–89.Google Scholar
  23. 23.
    J. A. S. Green and E. N. Pugh:Met. Trans., 1971, vol. 2, pp. 1379–83.Google Scholar

Copyright information

© The Minerals, Metals & Materials Society - ASM International - The Materials Information Society 1971

Authors and Affiliations

  • E. N. Pugh
    • 1
  • J. A. S. Green
    • 2
  1. 1.University of Illinois at Urbana-Champaign
  2. 2.RIASBaltimoreUSA

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