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Growth and Dissolution of Protective Oxide Films on Titanium: an in-Situ Neutron Reflectivity Study

Published online by Cambridge University Press:  22 February 2011

D.G. Wlesler  and
C.F. Majkrzak
D.G. Wlesler
Affiliation:
Department of Physics, George Washington University, 725 21st St. NW, Washington, DC 20074
C.F. Majkrzak
Affiliation:
Reactor Radiation Division, National Institute of Standards and Technology, Gaithersburg, MD 20899
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Abstract

The structure and morphology of titanium thin film electrodes have been investigated by neutron reflectometry. This technique yields a detailed depth profile of the scattering density, which is used to determine hydrogen and oxygen concentration profiles within the electrode. By depositing the electrode on a thick silicon crystal window, we are able to monitor the growth and dissolution of the protective oxide film covering the titanium as a function of time, electrode potential, and electrolyte composition. We find that, in 0.1 N sulfuric acid, the oxide dissolves at 0.7 A/h and is self-healing, meaning that as the oxide dissolves the metal underneath is oxidized to maintain a protective barrier. In contrast, when a -2 V cathodic bias is applied to a passive film, the oxide thins with no compensating oxide growth underneath, and the film undergoes electrochemical breakdown.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 376: Symposium BB – Neutron Scattering in Materials Science , 1994 , 247
Copyright
Copyright © Materials Research Society 1995

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References

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