Jan Philipp Kollender, Achim Walter Hassel,
"In Situ Monitoring of Ionic Metal Dissolution During Anodization of Titanium and Quantification of Parallel Electronic Oxygen Evolution"
, in ChemElectroChem, Vol. 4, Seite(n) 1846-1848, 5-2017
In Situ Monitoring of Ionic Metal Dissolution During Anodization of Titanium and Quantification of Parallel Electronic Oxygen Evolution
Sprache des Titels:
This study reports an in situ investigation of the metal dissolution
during anodization of titanium. A combination of an electrochemical flow cell that is directly coupled to an ICP-MS
was used for the investigation. The oxide film was grown through potentiodynamic anodization (CV with 10 mVs-1)
between 0 and 8 V. A rather constant dissolution rate of approximately 1.5 ngs-1 cm-2 was observed during the entire
oxide formation although the current, as measured by the potentiostat, increased from 58 mAcm-2 (1 V) up to 290 mAcm-2 (8 V).
Controversially, the dissolution rate was not affected by the additional electronic currents, which become relevant
for potentials higher than 3.5 V. The metal dissolution is triggered by the ionic species (Ti4+ and O2-) crossing the
oxide layer (ionic currents) under the applied high-field conditions. No reduction of the oxide during the reverse
scan could be observed. The fraction of charge carriers used for metal dissolution stayed rather constant (ca. 21%)
up 3.5 V, and then continuously decreased to 4% for the highest applied anodization potential (8.0 V), reflecting the
increased oxygen evolution rate at a rather constant dissolution rate.