Electrochemical and XPS studies of the corrosion behavior of sputter-deposited W-Nb alloys in concentrated hydrochloric acid solutions

Bhattarai, Jagadeesh; Akiyama, Eiji; Habazaki, H.; Kawashima, A.; Asami, K.; Hashimoto, Kôji

doi:10.1016/s0010-938x(97)00108-x

Cited by 33 publications

(23 citation statements)

References 36 publications

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“…The similar synergistic effect has been reported by the present author for the sputter-deposited W-xCr alloys. 7 It is noteworthy to mention here that corrosion rates of the sputter-deposited ternary W-Cr-(4-15)Ni alloys are lower than that of the sputter-deposited binary W-15Ni alloy, and higher than those of the binary W-(18-75)Cr alloys. These results revealed that the addition of chromium to the sputter-deposited binary W-Ni alloys is effective in enhancing the corrosion resistance in 12 M HCl, while a small addition of nickel to the binary W-Cr alloys is not effective to improve the corrosionresistant properties of the ternary W-Cr-Ni alloys.…”

Section: Methodsmentioning

confidence: 67%

“…This allows us to examine the formation of homogeneous or heterogeneous surface films formed on the alloys. [2][3][4][5][6][7][8][9] A non-destructive angleresolved XPS technique has been used by a number of researchers to gain information about in-depth concentration profiles of the passive films. In principle, the depth information of the passive film depends on the effective escape depth of photoelectrons, which increases with increase in the take-off angle of photoelectrons relative to the surface of the specimen.…”

Section: Introductionmentioning

confidence: 99%

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X-ray Photoelectron Spectroscopic Analyses on the Corrosion-Resistant W-Cr-Ni Alloys in 12 M HCl

Bhattarai

2010

Trans. Mat. Res. Soc. Japan

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The high corrosion behavior of the sputter-deposited amorphous or/and nanocrystalline WCr-(4-15)Ni alloys was investigated by corrosion tests, electrochemical measurements and X-ray photoelectron spectroscopy (XPS) including angle-resolved measurements in 12 M HCl at 30 o C, open to air. Particular attention was paid to the effects of tungsten, chromium and nickel metals addition on the surface composition of the passive films formed on the ternary alloys which is related to the corrosion-resistant as well as the anodic passivity of the alloys. Corrosion rates of the alloys (~ 0.85-3.00 x 10 -2 mm/y) are about four and three orders of magnitude lower than pure chromium and nickel, respectively, and even slightly lower than tungsten metal. Surface analyses by XPS including angle-resolved measurements revealed that the high corrosion resistance of the ternary W-Cr-(4-15)Ni alloys is mostly due to the formation of homogeneous passive oxyhydroxide films consisting of all alloying cations of the alloys. The beneficial effect of the simultaneous addition of chromium and tungsten is based mainly on the synergistic interaction between chromium and tungsten cations in the homogeneous oxyhydroxide passive films to improve the corrosion behavior as well as the passivity of the W-Cr-(4-15)Ni alloys in 12 M HCl.

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Section: Methodsmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

X-ray Photoelectron Spectroscopic Analyses on the Corrosion-Resistant W-Cr-Ni Alloys in 12 M HCl

Bhattarai

2010

Trans. Mat. Res. Soc. Japan

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“…potentiostatically or potentiodynamically) in order to understand the anodic passivity of the alloys or metals [1]. The measurement of the anodic potentiodynamic or/and potentiostatic polarization curves gives us a clear understanding as to what conditions are necessary to achieve the stable anodic passivity and the high corrosion resistance of the metals or alloys in the given aggressive environments.…”

Section: Introductionmentioning

confidence: 99%

“…However, the most interesting fact has been reported, during last two decades, that the corrosion rates of the sputter-deposited Cr-Nb [13,16,17] and Mo-Nb [14,17] alloys were lower than those of alloy constituting elements due to the spontaneous passivation in aggressive HCl solutions. Such interesting findings of the lower corrosion rates of Cr-Nb and Mo-Nb alloys than those of alloy constituting elements encouraged the present author to tailor high corrosion resistance W-Nb alloys by sputtering [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…It has been reported that the high corrosion resistance of the sputter-deposited tungsten−based binary [18][19][20][22][23][24][25] and ternary [26,27] alloys in 12 M HCl was based on the formation of new passive double oxyhydroxide films of tetravalent tungsten and alloy-constituting cations. The tetravalent tungsten is the main oxidation state of tungsten for these tungsten-based binary alloys at +0.2 V (SCE) or lower potentials, while the hexavalent tungsten is the main oxidation state of tungsten at +0.4 V (SCE) or higher potentials in hydrochloric acid solutions.…”

Section: Introductionmentioning

confidence: 99%

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X-ray Photoelectron Spectroscopic Study on the Anodic Passivity of Sputter-deposited W-Nb Alloys in 12 M HCl Solution

Bhattarai

2011

J. Sci. Res.

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The effect of a simultaneous additions of tungsten and niobium on the anodic passivity of the surface films of the sputter−deposited amorphous/nanocrystalline W-xNb alloys was studied using corrosion tests, electrochemical measurements and X-ray photoelectron spectroscopic (XPS) analyses. The formation of spontaneous passive film on the alloys, which is composed of double oxyhydroxides of W ox and Nb 5+ ions, is responsible for their higher corrosion resistance than those of the alloy-constituting elements in 12 M HCl solution open to air at 30°C. The quantitative surface analysis by XPS clarifies that the improved anodic passivity of the alloys than those of alloy-constituting elements is based on the formation of new double oxyhydroxide anodic films composed of W 6+ and Nb 5+The passivity of metals or alloys is a subject of significant research in the fields of corrosion science and engineering. The mechanisms of passive film formation and the nature of the passive films can be understood by modern electrochemical theories with the aid of potentiostatic or/and galvanostatic polarization measurements. The change in the current density as a function of polarization potential (that is, deviation of potentials away from equilibrium) represented in the polarization diagrams, and several processes related to corrosion and passivation can be easily understood with the help of the polarization diagrams of the alloys or metals. It must be remembered that experiments have to be performed by controlling the potential and measuring the current (that is, either by ions. These anodic passive films have higher protectiveness and stability than those of the anodic passive oxyhydroxide films of alloy-constituting elements, that is, oxyhydroxides of hexavalent tungsten and pentavalent niobium after potentiostatic polarization for 1 h in 12 M HCl at 30°C.

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Metastable Alloys

Hashimoto

2011

Uhlig's Corrosion Handbook

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A. Structural characteristics B. Corrosion-resistant alloys in aqueous solutions C. Factors determining the high corrosion resistance of amorphous alloys C1. Passive films rich in cations of alloying elements with high passivating ability C2. Homogeneous nature of amorphous alloys C3. High activity of amorphous alloys D. Alloys resistant to aqueous corrosion D1. Aluminum corrosion-resistant metal alloys D2. Chromium-refractory metal alloys D3. Molybdenum corrosion-resistant metal alloys D4. Tungsten corrosion-resistant metal alloys E. Alloys resistant to sulfidizing/oxidizing environments at high temperatures F. Summary References A. STRUCTURAL CHARACTERISTICSAmorphous alloys consist of at least two components and have no long-range atomic order. They are produced by a variety of methods based on rapid solidification of the alloy constituents from the gas, liquid, and aqueous phases. Mechanical alloying, that is, solid-state mixing, is also effective for preparation of amorphous alloy powders. Vitrification of metal surfaces is also made by destruction of the long-range atomic order in the surfaces of solid metals.The formation of the structure with no long-range atomic order is based on the prevention of solid-state diffusion during solidification, and hence the alloys are free of compositional fluctuations formed by solid-state diffusion, such as second phases, precipitates, and segregates. The amorphous alloys are therefore regarded as ideal, chemically homogeneous alloys composed of thermodynamically metastable single-phase solid solutions supersaturated with alloy constituents. This characteristic is particularly suitable in producing new alloys possessing specific properties. Even if amorphous single-phase alloys are not formed, alloys prepared by amorphization methods are often composed of nanocrystalline phases supersaturated with alloying elements. From a corrosion point of view they can be considered as homogeneous alloys. B. CORROSION-RESISTANT ALLOYS IN AQUEOUS SOLUTIONSThe corrosion behavior of amorphous alloys has received particular attention since the extraordinarily high corrosion resistance of amorphous Fe-Cr-metalloid alloys was reported in 1974 [1]. The preparation of amorphous iron-based alloys by rapid quenching from the liquid state using melt spinning generally requires the alloys to contain large amounts of metalloids, which are mostly close to the eutectic compositions.The addition of chromium to amorphous Fe-metalloid alloys is particularly effective in enhancing corrosion resistance. For instance, amorphous Fe-8Cr-13P-7C alloy passivates spontaneously even in 2 M HCI at ambient temperature [2]. (The number denoting the concentration of an alloy element in amorphous alloy formulas is expressed as an atomic percent unless otherwise stated.)Uhlig's Corrosion Handbook, Third Edition, Edited by R. Winston Revie

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Electrochemical and XPS studies of the corrosion behavior of sputter-deposited W-Nb alloys in concentrated hydrochloric acid solutions

Cited by 33 publications

References 36 publications

X-ray Photoelectron Spectroscopic Analyses on the Corrosion-Resistant W-Cr-Ni Alloys in 12 M HCl

X-ray Photoelectron Spectroscopic Analyses on the Corrosion-Resistant W-Cr-Ni Alloys in 12 M HCl

X-ray Photoelectron Spectroscopic Study on the Anodic Passivity of Sputter-deposited W-Nb Alloys in 12 M HCl Solution

Metastable Alloys

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