Corrosion Behaviour of Copper– nickel Alloys in LiBr Solutions: A Comparative Study

Document Type : Original Article

Authors

1 Department of Physical Chemistry, National Research Center, Giza, Egypt.

2 Physical Chemistry Department, Faculty of Science, Ain Shams University, Abbasia, Cairo, Egypt.

Abstract

THE ANODIC potentiodynamic cyclic polarization behavior of Cu/10 Ni and Cu/30 Ni alloys in different wide range of LiBr concentrations from 10-1 to 9 M was investigated. The results obtained showed that the breakdown potential, hysteresis loop area and passive current were recorded at higher value of potentials in case of Cu/10 Ni in comparison with Cu/30 Ni. The current density showed higher values during the first few moment of polarization of both alloys studied as result of the changes the taking place on the surface. At 5x10-1 M of LiBr, in case of Cu/10 Ni, two breakdown potentials yielded two hysteresis loops, one of them was at 700 mV and the second was at more anodic potential. These are not recorded in case of Cu/30 Ni where pitting corrosion was manifested at 2 and 4 M LiBr only. The current – time measurement and surface examination of the electrode in case of Cu/30 Ni at 3x10-1 and 5x10-1M LiBr showed that the film formed at low anodic potential of 150 mV clarify the formation of small number of initiated pits which are surrounded by a passive and protective film of doped Cu2O and the surface shown enrichment of Ni. While at all the potential studied for the Cu/10 Ni and Cu/30 Ni the surface of the alloy suffered from denickelification.

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History

  • Receive Date: 22 July 2019
  • Revise Date: 30 July 2019
  • Accept Date: 01 August 2019

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