Characterization of sol-gel-derived TiO{sub 2} coatings and their photoeffects on copper substrates
- Univ. of Tokyo (Japan). Dept. of Metallurgy
In accordance with the corrosion protection of Cu by n-TiO{sub 2} coating under illumination, the relation between the structural characterization and the photoelectrochemical properties of sol-gel-derived TiO{sub 2} coating has been investigated utilizing glow discharge spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analysis technique. As a result of the well-known shrinkage of the gel under heat-treatment, the thickness of the TiO{sub 2} coating decreased with increasing heating temperature, about a 50% decrease from 200 to 800 C. Amorphous TiO{sub 2} gel was found to be crystallized about 400 C, which gave rise to a great enhancement of the photocurrent of the TiO{sub 2} coating. In relating these results to the existence of Cu oxides in the coating were not the direct reasons which accounted for the critical temperature for TiO{sub 2} to impose its photoeffects on the Cu substrate. The dramatic change in the photopotential of TiO{sub 2}-coated Cu would be explained by the change of Schottky barrier at the TiO{sub 2}/Cu interface in terms of the Fermi level pinning at the Ti{sup 3+} defect level. Nevertheless, the increase in the photocurrent of TiO{sub 2} coating was beneficial to move the photopotential of TiO{sub 2} coated Cu to a much less noble level. The degradation of the photoeffect of TiO{sub 2} coating heated above 800 C was due to the significant diffusion of Cu into the coating.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 131778
- Journal Information:
- Journal of the Electrochemical Society, Vol. 142, Issue 10; Other Information: PBD: Oct 1995
- Country of Publication:
- United States
- Language:
- English
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