Ellipsometric Study Dissolution of Anodic WO3 Films in Aqueous Solutions. 2. Reaction Mechanism".

M. A. PÉREZ AND M. LÓPEZ TEIJELO.

JOURNAL OF PHYSICAL CHEMISTRY B

Año: 2005 vol. 109 p. 19369 - 19369

1089-5647

he present work demonstrates that the dissolution of anodic WO3 can be described in terms of general mechanisms already used to account for the physicochemical processes involved in the dissolution of oxides of other metals. The chemical dissolution of anodic WO3 films is  characterized by in situ ellipsometry, which has proven to be a suitable technique for studying the processes taking place.1 The capability of ellipsometry for distinguishing between thickness decrease and hydration and generation of porosity/roughness helps to analyze the thickness range within which reliable kinetic information can be obtained. The dissolution rate law found for anodic WO3 does not depend on the oxide thickness. The dissolution of anodic WO3 filmsincludes hydration and roughening, besides thickness decrease, and is kinetically controlled by the OH concentration at the oxide/electrolyte interface. Apart from OH-, the specific nature of electrolyte anions seems to play no kinetic role, ex