A Redox Printing Technique for the Study of the Electronic Conductivity of Anodic Oxide Films on Valve Metals

Klein, Gerhart P.

doi:10.1149/1.2423958

Cited by 14 publications

(3 citation statements)

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“…The anodic printing technique described in an earlier paper (8) was used to study the electronic currents in the oxide films; we refer to that paper for experimental details.…”

Section: Methodsmentioning

confidence: 99%

The Electronic Conductivity of Defective Anodic Tantalum Oxide Films

Klein¹

1966

J. Electrochem. Soc.

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The conditions under which anodic oxide films on tantalum showed electronic conductivity were studied using an electrochemical printing‐out technique with starch‐iodide as the redox indicator. The sensitivity for the detection of electronic charge was approximately 1 millicoulomb/cm2. The effect of alloying (contamination), thermal oxidation, plastic deformation, and surface topography were investigated with regard to their contribution to the electronic conductivity of anodic oxide films on mechanically treated (“rough”) tantalum surfaces. It was concluded that impurities alone were responsible for the electronic conductivity even in cases where supposedly clean tantalum had been abraded with tantalum. Roughness by itself was not a sufficient condition for electronic conductivity.

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“…The anodic printing technique described in an earlier paper (8) was used to study the electronic currents in the oxide films; we refer to that paper for experimental details.…”

Section: Methodsmentioning

confidence: 99%

The Electronic Conductivity of Defective Anodic Tantalum Oxide Films

Klein¹

1966

J. Electrochem. Soc.

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“…Multiple scans of the spectra were obtained and five-point smoothing was used to improve the signal-to-noise ratio. For peak-area analysis, the nonlinear background subtraction technique of Shirley (13) was used. The curve fitting program used a mixed Gaussian/Lorentzian product function (14), in which the position (energy), intensity, and FWHM (full width at half-maximum peak height) parameters were first assigned approximate values and then allowed to float and be optimized by the program.…”

Section: Introductionmentioning

confidence: 99%

“…The typical thickness of the dry, air-formed oxide is 2-4 rim. Although, in principle, the oxide is an electronic insulator with a bandgap energy of 7 eV (3,4), in solution it becomes an electronic and ionic conductor at specific "defective" or "contaminated" oxide sites (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17), the exact nature of which remains controversial (6). It is known that the number density of such sites increases with the addition of transition metals as alloying elements or impurities.…”

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confidence: 99%

Localized Corrosion of Sputtered Aluminum and Al‐0.5% Cu Alloy Thin Films in Aqueous HF Solution: I . Corrosion Phenomena

Scully

Frankenthal

Hanson

et al. 1990

J. Electrochem. Soc.

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The corrosion of sputter-deposited aluminum and A1-0.5 weight percent Cu alloy thin film metallizations and of highpurity aluminum foil has been investigated in dilute aqueous HF solutions. Using ac and dc electrochemical techniques and optical and electron analytical techniques, the solution and metallurgical conditions that lead to localized breakdown of the passivating film and subsequent micropitting of aluminum and the alloy have been established. Micropitting occurs at potentials as negative as the open-circuit potential, which for aluminum is 1.2V negative of the oxide breakdown potential, i.e., the pitting potential. Al2Cu precipitates in the alloy depolarize the cathodic reaction causing an increase in pit density and in the rate of pit growth.

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Quantitative Measurement and Imaging of Metal Fatigue

Baxter

1983

Review of Progress in Quantitative Nondestructive Evaluation

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A simple electrochemical technique is described, which images and quantitatively measures the distribution and severity of fatigue damage in aluminum alloys. The technique is based upon (i) the creation of microcracks in a surface anodic oxide film during fatigue of the underlying metal, and (ii) the detection of these microcracks by contacting the surface with a gel electrode. When a voltage pulse is applied, current passes through the fatigue--induced microcracks in the oxide film, and an image of the sites of current flow is retained in the surface of the gel. The capabilities of the technique are illustrated by measurements on 6061-T6, 7075-T6 and 2024-T4 aluminum. The electrochemically formed images correlated directly with scanning electron micrographs of the specimens. Hairline fatigue cracks ~10 ~ long are easily imaged, while the charge flow during the formation of the image is a quantitative measure of the crack length. The accumulation of fatigue deformation prior to the appearance of a fatigue crack is also detected, and in this regard the sensitivity of the gel electrode exceeds that of a scanning electron microscope. The distribution of fatigue deformation may be mapped as early as 1% of the fatigue life, and the charge flow to the regions of most severe damage increases systematically with fatigue cycling as the density of microcracks in the oxide increases.The simplicity of this electrochemical gel electrode method renders it directly applicable to field investigations, and provides a new tool for quantitatively assessing the distribution of fatigue damage. 1039 1040 W.J. BAXTER

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A Redox Printing Technique for the Study of the Electronic Conductivity of Anodic Oxide Films on Valve Metals

Cited by 14 publications

References 0 publications

The Electronic Conductivity of Defective Anodic Tantalum Oxide Films

The Electronic Conductivity of Defective Anodic Tantalum Oxide Films

Localized Corrosion of Sputtered Aluminum and Al‐0.5% Cu Alloy Thin Films in Aqueous HF Solution: I . Corrosion Phenomena

Quantitative Measurement and Imaging of Metal Fatigue

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