Anodic films were grown potentiodynamically in different electrolytes (pH = 1–14) on a Ti–50Zr at% cast alloy, obtained by fusion in a voltaic arc under argon atmosphere. The thickness of the filmswas varied by changing formation potential from the open circuit potential up to about 9V; growth was followed by 30 min stabilization at the forming potential. Films having different thicknesses were characterized by photocurrent spectroscopy (PCS) and electrochemical impedance spectroscopy (EIS). Moreover, film composition was analyzed by X-ray photoelectron spectroscopy (XPS). Regardless of the anodizing conditions, passive films on the Ti–50Zr at% alloy consist of a single layer mixed oxide phase containing both TiO2 and ZrO2 groups. However, an enrichment of Ti within the passive film, increasing with the film thickness, is detected both by PCS and XPS. This leads to concentration profiles of Ti4+ and Zr4+ ions along the thickness, and to different electronic properties of very thin films (more insulating) with respect to thicker films (more semiconducting), as revealed by the photocurrent–potential curves.

OLIVEIRA NTC, BIAGGIO SR, NASCENTE PAP, PIAZZA S, SUNSERI C, DI QUARTO F (2006). The effect of thickness on the composition of passive films on a Ti-50Zr at% alloy. ELECTROCHIMICA ACTA, 51, 3506-3515 [10.1016/j.electacta.2005.10.007].

The effect of thickness on the composition of passive films on a Ti-50Zr at% alloy

PIAZZA, Salvatore;SUNSERI, Carmelo;DI QUARTO, Francesco
2006-01-01

Abstract

Anodic films were grown potentiodynamically in different electrolytes (pH = 1–14) on a Ti–50Zr at% cast alloy, obtained by fusion in a voltaic arc under argon atmosphere. The thickness of the filmswas varied by changing formation potential from the open circuit potential up to about 9V; growth was followed by 30 min stabilization at the forming potential. Films having different thicknesses were characterized by photocurrent spectroscopy (PCS) and electrochemical impedance spectroscopy (EIS). Moreover, film composition was analyzed by X-ray photoelectron spectroscopy (XPS). Regardless of the anodizing conditions, passive films on the Ti–50Zr at% alloy consist of a single layer mixed oxide phase containing both TiO2 and ZrO2 groups. However, an enrichment of Ti within the passive film, increasing with the film thickness, is detected both by PCS and XPS. This leads to concentration profiles of Ti4+ and Zr4+ ions along the thickness, and to different electronic properties of very thin films (more insulating) with respect to thicker films (more semiconducting), as revealed by the photocurrent–potential curves.
2006
Settore ING-IND/23 - Chimica Fisica Applicata
OLIVEIRA NTC, BIAGGIO SR, NASCENTE PAP, PIAZZA S, SUNSERI C, DI QUARTO F (2006). The effect of thickness on the composition of passive films on a Ti-50Zr at% alloy. ELECTROCHIMICA ACTA, 51, 3506-3515 [10.1016/j.electacta.2005.10.007].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/5668
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