The growth behavior of amorphous anodic films on Ta–Nb solid solution alloys has been investigated over a wide composition range at a constant current density of 50 Am−2 in 0.1 mol dm−3 ammonium pentaborate electrolyte. The anodic films consist of two layers, comprising a thin outer Nb2O5 layer and an inner layer consisting of units of Ta2O5 and Nb2O5. The outer Nb2O5 layer is formed as a consequence of the faster outward migration of Nb5+ ions, compared with Ta5+ ions, during film growth under the high electric field. Their relative migration rates are independent of the alloy composition. The formation ratio, density, and capacitance of the films show a linear relation to the alloy composition. The susceptibility of the anodic films to field crystallization during anodizing at constant voltage increases with increasing niobium content of the alloy.

Komiyama S, Tsuji E, Aoki Y, Habazaki H, Santamaria M, Di Quarto F, et al. (2012). Growth and field crystallization of anodic films on Ta–Nb alloys. JOURNAL OF SOLID STATE ELECTROCHEMISTRY, 16 (4) , pp. 1595-1604 [DOI 10.1007/s10008-011-1565-7].

Growth and field crystallization of anodic films on Ta–Nb alloys

SANTAMARIA, Monica;DI QUARTO, Francesco;
2012

Abstract

The growth behavior of amorphous anodic films on Ta–Nb solid solution alloys has been investigated over a wide composition range at a constant current density of 50 Am−2 in 0.1 mol dm−3 ammonium pentaborate electrolyte. The anodic films consist of two layers, comprising a thin outer Nb2O5 layer and an inner layer consisting of units of Ta2O5 and Nb2O5. The outer Nb2O5 layer is formed as a consequence of the faster outward migration of Nb5+ ions, compared with Ta5+ ions, during film growth under the high electric field. Their relative migration rates are independent of the alloy composition. The formation ratio, density, and capacitance of the films show a linear relation to the alloy composition. The susceptibility of the anodic films to field crystallization during anodizing at constant voltage increases with increasing niobium content of the alloy.
Settore ING-IND/23 - Chimica Fisica Applicata
Komiyama S, Tsuji E, Aoki Y, Habazaki H, Santamaria M, Di Quarto F, et al. (2012). Growth and field crystallization of anodic films on Ta–Nb alloys. JOURNAL OF SOLID STATE ELECTROCHEMISTRY, 16 (4) , pp. 1595-1604 [DOI 10.1007/s10008-011-1565-7].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/73254
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