Kinetics of copper passivation and pitting corrosion in Na<sub>2</sub>SO<sub>4</sub> containing dilute NaOH aqueous solution

The electrochemical behaviour of Cu in alkaline solutions containing Na<sub>2</sub>SO<sub>4</sub> was studied using potentiodynamic and potentiostatic techniques complemented by scanning electron microscopy. The presence of Na<sub>2</sub>SO<sub>4</sub>...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Souto, Ricardo M., González, Sergio G., Salvarezza, Roberto Carlos, Arvia, Alejandro Jorge
Formato:	Articulo
Lenguaje:	Inglés
Publicado:	1994
Materias:	Ciencias Exactas Química Cobre Metales Alcalinos Sulfatos Sodio scanning electron microscopy electrodissolution Cinética química Electroquímica
Acceso en línea:	http://sedici.unlp.edu.ar/handle/10915/86541
Aporte de:	SEDICI (UNLP) de Universidad Nacional de La Plata

Descripción
Sumario:	The electrochemical behaviour of Cu in alkaline solutions containing Na<sub>2</sub>SO<sub>4</sub> was studied using potentiodynamic and potentiostatic techniques complemented by scanning electron microscopy. The presence of Na<sub>2</sub>SO<sub>4</sub> enhances Cu electrodissolution through the passive layer and decreases the breakdown potential. There is a critical OH<sup>-</sup>/sulphate concentration ratio for the onset of localized corrosion. The competitive interaction between OH<sup>-</sup> and sulphate ions at the passive layer can explain the experimental data. Pit initiation fits the point defect model for passivity breakdown. Pit growth involves a number of current contributions which can be distinguished through the analysis of current transients at constant potential by using nucleation and growth models.