Original scientific paper
Determination of refractive index and thickness of anodic oxide films on aluminium by a galvanoluminescent method
Ljubiša D. Zeković
; Institute of Physics, P. 0. Box S7, 11001 Beograd, Yugoslavia
Vladeta V. Urošević
; Institute of Physics, P. 0. Box S7, 11001 Beograd, Yugoslavia
Branislav R. Jovanić
; Institute of Physics, P. 0. Box S7, 11001 Beograd, Yugoslavia
Bratimir Panić
; Institute of Physics, P. 0. Box S7, 11001 Beograd, Yugoslavia
Aleksandar Žikić
; Department of Physics, Faculty of Sciences, P. 0. Box SSO, 11001 Beograd, Yugoslavia
Abstract
In this work a galvanoluminescent method is described which makes possible determination of both thickness (or growth rate) and refractive index of thin oxide films formed by anodic oxidation of valve metals. The method is based on the analysis of positions of interference maxima which appear during the anodization on Iλ (t) curves when the emitted radiation is detected both normal and parallel to the oxide film surface within a small (α ≤ 5°) acceptance angle. For anodic alumina formed in 0.1 M oxalic acid at constant current density (j = 12.5 mA/cm2) and temperature (T = 300.6 K), the refractive index n2 = 1.63 ± 0.02 (mean value for wavelength interval 400-580 nm) has been obtained in a rather good agreement with Huber and Gaugler (1.65 ± 0.02). The value of anodizing rate α = (0.468 ± 0.005) nm/s/mA/cm2) is about 10% smaller than the results obtained by Golubiev and Diggle et al. under rather different anodizing conditions.
Keywords
Hrčak ID:
331454
URI
Publication date:
5.12.1988.
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