Kinetics and mechanism of the nickel electrode : II. Acid solutions containing a high concentration of sulphate and nickel ions

The kinetics of the Ni electrode in acid solutions with a high sulphate and nickel ion concentration has been investigated in the range of 25–75°C. The active dissolution and the passive regions and the active-passive transition phenomena have been studied employing different potential perturbation...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Vilche, Jorge Roberto, Arvia, Alejandro Jorge
Formato: Articulo
Lenguaje:Inglés
Publicado: 1978
Materias:
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/82561
Aporte de:
Descripción
Sumario:The kinetics of the Ni electrode in acid solutions with a high sulphate and nickel ion concentration has been investigated in the range of 25–75°C. The active dissolution and the passive regions and the active-passive transition phenomena have been studied employing different potential perturbation techniques using both still and stirred solutions. Two electrochemical processes are competing within the prepassive film potential region, namely, the active Ni dissolution to Ni(II) ions and the Ni(OH)<sub>2</sub> film formation. Nickel passivation is explained by reaction pathways involving successive electrochemical and chemical steps implying the occurrence of hydroxo- and oxo-species as reactions intermediates. The advanced mechanism is based upon a positively charged Ni surface structure and attributes the onset of the complete passivity to a particular surface oxide species.