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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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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