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Electrochemical Passivation of Niobium in KOH Solutions

Irena Mickova
Abdurauf Prusi
Toma Grcev
Ljubomir Arsov

Sažetak

Electrochemical formation and dissolution of passive films on niobium surfaces were studied in various concentrations of KOH solutions using the open-circuit potential and potentiodynamic techniques. Potentiodynamic I/E profiles indicated that the electrolyte concentration strongly affects the active/passive transition, as well as the values of the passivation potentials and critical currents. At higher KOH solution concentrations, after passivation of the electrode surface in the first positive cyclic voltammetry scan, reactivation processes were monitored in the reverse scan. Formation of passive films is a diffusion-controlled process only for higher sweep rates. Cathodic pretreatment of niobium electrode affects the chemical structure and oxide composition of passive films. Corrosion measurements have shown that at higher KOH concentrations the passive film is rapidly attacked and the corrosion resistance of Nb electrode is drastically diminished.

Ključne riječi

niobium electrode; passive films; open circuit potential; potentiodynamic data

Hrčak ID:

5758

URI

https://hrcak.srce.hr/5758

Datum izdavanja:

13.12.2006.

Posjeta: 2.875 *