Kinetics of passivation and pitting corrosion of polycrystalline copper in borate buffer solutions containing sodium chloride

Authors
Gennero de Chialvo, Maria Rosa; Salvarezza, Roberto Carlos; Vásquez Moll, Victor Dennis; Arvia, Alejandro Jorge
Publication Year
1985
Language
English
Format
article
Status
Published version
Description
The pitting corrosion of copper in borate buffer containing sodium chloride is studied by using potentiostatic and potentiodynamic techniques complemented with scanning electron microscopy and EDAX. The breakdown potential shifts towards more negative values as the sodium chloride concentration increases. During pitting both soluble Cu(I) and Cu(II) species are detected. The first stage of pitting is explained through the competition between the passive layer formation and the nucleation and growth of the CuCl layer in equilibrium with Cu(I)-chloride complexes in solution. When salt nuclei reach the metal surface, pit growth under charge-transfer control is found. In the following stage the kinetics of pit growth changes to a diffusion controlled process when the thick CuCl layer is completed. Secondary breakdown of the salt layer results in copper dissolution through Cu(II) soluble species. The corresponding overall process is discussed in terms of a sum of nucleation and growth processes. The reaction model reproduces the potentiostatic current transients of copper in weakly alkaline borate buffer containing sodium chloride.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)
Facultad de Ciencias Exactas
Subject
Ciencias Exactas
Química
Access level
Open access
License
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
Repository
SEDICI (UNLP)
Institution
Universidad Nacional de La Plata
OAI Identifier
oai:sedici.unlp.edu.ar:10915/79490