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Title: Optical Properties of Anodic Oxide Films on Tantalum, Niobium, and Tantalum + Niobium Alloys, and the Optical Constants of Tantalum

Abstract

The reflectivity of anodized electropolished tantalum was measured as a function of angle of incidence for 4358A light polarized in the plane of incidence. The principal aim of these measurements was to obtain the refractive index of the oxide. This is needed to determine absolute thicknesses of oxide by the spectrophotometric method in which the wavelengths of minimum reflectivity due to interference at near normal incidence are determined. The measurements also provided a method of determining the optical constants of the metal, without assuming that the surface is perfectly flat or that an unsnodized surface is free from oxide. It was found that films formed on tantalum in 0.2N H/sub 2/SO/sub 4/ have a thin outer layer of light-absorbing oxide. The bulk of the film is, however, nonabsorbing and homogeneous. A large part of the thickness of films formed in concentrated sulfuric acid absorbs light. The refractive index at 4358A wavelength of films formed in dilute solution increases by about 0.3% per tenfold decrease in the current density at which they are made and by about 0.06% per 10 deg C rise in the temperature at which they are made. The refractive indices of films formed on niobium, on 25more » at.% Ta--75 at.% Nb, snd on 25 at.% Nb-- 75 at.% Ta were estimated and a preliminary study was made of films on zirconium.« less

Authors:
; ;
Publication Date:
Research Org.:
Univ. of British Columbia, Vancouver
Sponsoring Org.:
USDOE
OSTI Identifier:
4017980
NSA Number:
NSA-15-017262
Resource Type:
Journal Article
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 108; Journal Issue: 5; Other Information: Orig. Receipt Date: 31-DEC-61; Journal ID: ISSN 0013-4651
Publisher:
The Electrochemical Society
Country of Publication:
Country unknown/Code not available
Language:
English
Subject:
METALS, CERAMICS, AND OTHER MATERIALS; ANODES; FILMS; NIOBIUM; NIOBIUM ALLOYS; OPTICAL PROPERTIES; OXIDES; QUANTITATIVE ANALYSIS; SPECTROMETERS; SULFURIC ACID; TANTALUM; TANTALUM ALLOYS; THICKNESS; ZIRCONIUM

Citation Formats

Masing, L., Orme, J. E., and Young, L. Optical Properties of Anodic Oxide Films on Tantalum, Niobium, and Tantalum + Niobium Alloys, and the Optical Constants of Tantalum. Country unknown/Code not available: N. p., 1961. Web. doi:10.1149/1.2428105.
Masing, L., Orme, J. E., & Young, L. Optical Properties of Anodic Oxide Films on Tantalum, Niobium, and Tantalum + Niobium Alloys, and the Optical Constants of Tantalum. Country unknown/Code not available. doi:10.1149/1.2428105.
Masing, L., Orme, J. E., and Young, L. Sun . "Optical Properties of Anodic Oxide Films on Tantalum, Niobium, and Tantalum + Niobium Alloys, and the Optical Constants of Tantalum". Country unknown/Code not available. doi:10.1149/1.2428105.
@article{osti_4017980,
title = {Optical Properties of Anodic Oxide Films on Tantalum, Niobium, and Tantalum + Niobium Alloys, and the Optical Constants of Tantalum},
author = {Masing, L. and Orme, J. E. and Young, L.},
abstractNote = {The reflectivity of anodized electropolished tantalum was measured as a function of angle of incidence for 4358A light polarized in the plane of incidence. The principal aim of these measurements was to obtain the refractive index of the oxide. This is needed to determine absolute thicknesses of oxide by the spectrophotometric method in which the wavelengths of minimum reflectivity due to interference at near normal incidence are determined. The measurements also provided a method of determining the optical constants of the metal, without assuming that the surface is perfectly flat or that an unsnodized surface is free from oxide. It was found that films formed on tantalum in 0.2N H/sub 2/SO/sub 4/ have a thin outer layer of light-absorbing oxide. The bulk of the film is, however, nonabsorbing and homogeneous. A large part of the thickness of films formed in concentrated sulfuric acid absorbs light. The refractive index at 4358A wavelength of films formed in dilute solution increases by about 0.3% per tenfold decrease in the current density at which they are made and by about 0.06% per 10 deg C rise in the temperature at which they are made. The refractive indices of films formed on niobium, on 25 at.% Ta--75 at.% Nb, snd on 25 at.% Nb-- 75 at.% Ta were estimated and a preliminary study was made of films on zirconium.},
doi = {10.1149/1.2428105},
journal = {Journal of the Electrochemical Society},
issn = {0013-4651},
number = 5,
volume = 108,
place = {Country unknown/Code not available},
year = {1961},
month = {1}
}