Enhancement of pure titanium localized corrosion resistance by anodic oxidation

Prando, Davide; Brenna, Andrea; Pedeferri, MariaPia; Ormellese, Marco

doi:10.1002/maco.201709815

Cited by 19 publications

(21 citation statements)

References 32 publications

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“…As the duration of each test did not exceed 8h, no sealing was necessary. Previous works on titanium oxide tested in such conditions showed that nor chemical (ΔpH ≈ 0.05) nor physical (ΔT ≈ 2 °C) deviations were to be expected . In order to ensure repeatability, a minimum of three measurements were made for each treatment procedure.…”

Section: Methodsmentioning

confidence: 99%

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Corrosion resistance enhancement of chemically oxidized titanium through NaOH and H₂O₂ exposure

Prando

Nicolis

Bolzoni

et al. 2018

Materials & Corrosion

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Titanium owes its astounding corrosion resistance to a thin, compact oxide layer that is formed spontaneously when the metal is exposed to the environment. However, even titanium can be subject to corrosion in very aggressive environments. To enhance its corrosion resistance, it is possible to exploit the same mechanism that leads to the formation of the protective oxide layer and force its growth with an external contribution. Oxidation can be easily stimulated with the use of an electrochemical cell. However, when part geometry or dimensions do not allow the immersion in an anodizing bath, chemical oxidation can be used. This study compares corrosion resistance enhancement after NaOH and H2O2 treatment. Treatment duration and temperature, solution concentration, and quantity are optimized to achieve the best corrosion resistance with the least time and chemicals consumption, by maintaining the process easy to perform and safe for the operator.

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Section: Methodsmentioning

confidence: 99%

“…Anodic oxidation produces a compact, adherent, and corrosion resistant oxide and was studied in previous works . However, in case of already installed part, localized treatment, small part or complex geometry, anodic oxidation could be un‐feasible.…”

Section: Introductionmentioning

confidence: 99%

Corrosion resistance enhancement of chemically oxidized titanium through NaOH and H₂O₂ exposure

Prando

Nicolis

Bolzoni

et al. 2018

Materials & Corrosion

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“…The easiest and cheapest treatment to adjust oxide layer is anodic oxidation. It consists in applying an anodic polarization of several tens of volts to the metal, promoting the growth of a compact, adherent and corrosion resistant oxide with thicknesses ranging from about 40 nm with anodizing potential 10 V, to about 250 nm at 100 V. [22][23][24] However, in case of already installed part, localized treatment, small part or complex geometry, anodic oxidation could be un-feasible. In these cases chemical oxidation would be suitable to provide the corrosion resistance enhancement needed.…”

Section: *Manuscript Click Here To View Linked Referencesmentioning

confidence: 99%

“…As the duration of each test did not exceed 8h, no sealing was considered. Previous works on titanium oxide tested in such conditions showed that nor chemical (ΔpH ≈ 0.05) nor physical (ΔT ≈ 2°C) deviations were expected [24]. In order to ensure repeatability, a minimum of three measurements were made for each treatment.…”

Section: Corrosion Testmentioning

confidence: 99%

Chemical oxidation as repairing technique to restore corrosion resistance on damaged anodized titanium

Prando

Nicolis

Bolzoni

et al. 2019

Surface and Coatings Technology

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Anodized titanium shows an excellent resistance to pitting corrosion. However, it could be subject to failure in case of local removal of the oxide film due, for example, to incorrect handling during transport, installation, or use. Depending on part size and usage, an electrochemical anodizing treatment could be not feasible. In this case, localized chemical oxidation treatment could be used to recover damaged film and restore corrosion resistance. Chemical oxidation was performed on titanium by immersion in NaOH 10 M and H2O2 10 M at temperature from room to 90°C with duration ranging between 1h and 72h. Potentiodynamic tests in bromides 0.5 M were used to determine the effectiveness of the treatment in relation with the one obtained with anodic oxidation. Higher bath temperature led to faster growth of the film, however it has no effect on the final corrosion resistance. Breakdown potential in bromides increased with treatment duration. The establishment of a plateau occurs at earlier stage, as temperature is increased. Titanium samples anodized and then scratched, to simulate film mechanical removal, were recovered using chemical oxidation and initial corrosion resistance was restored. The suggested treatments for in-situ recovery are 72h of exposure to NaOH or 6h at H2O2 at room temperature. AbstractAnodized titanium shows an excellent resistance to pitting corrosion. However, it could be subject to failure in case of local removal of the oxide film due, for example, to incorrect handling during transport, installation, or use. Depending on part size and usage, an electrochemical anodizing treatment could be not feasible. In this case, localized chemical oxidation treatment could be used to recover damaged film and restore corrosion resistance. Chemical oxidation was performed on titanium by immersion in NaOH 10 M and H 2 O 2 10 M at temperature from room to 90°C with duration ranging between 1h and 72h. Potentiodynamic tests in bromides 0.5 M were used to determine the effectiveness of the treatment in relation with the one obtained with anodic oxidation. Higher bath temperature led to faster growth of the film, however it has no effect on the final corrosion resistance. Breakdown potential in bromides increased with treatment duration. The establishment of a plateau occurs at earlier stage, as temperature is increased. Titanium samples anodized and then scratched, to simulate film mechanical removal, were recovered using chemical oxidation and initial corrosion resistance was restored. The suggested treatments for in-situ recovery are 72h of exposure to NaOH or 6h at H 2 O 2 at room temperature.

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“…For TiAlV6‐4, there exists a high number of publications on the corrosion behavior in various media, due to the widespread technical use of this alloy. In comparison, less information about the growth mechanism of passivating anodic oxide films are available.…”

Section: Introductionmentioning

confidence: 99%

Micro‐electrochemical investigation of the passive behavior of thin anodic titanium oxide films on TiAlV6‐4

Langklotz

Noeske

Schneider

2018

Materials & Corrosion

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The present work describes the passive film behavior of thin anodic oxide films on polycrystalline TiAlV6‐4. Firstly, the influence of the microstructure was addressed. Therefore, the crystallographic grain orientations of the substrate were determined by EBSD and selected grains were investigated with an electrochemical micro‐capillary cell. The barrier‐like oxide films were produced by local anodization in an acetate buffered electrolyte (pH 5.9) and investigated by electrochemical impedance spectroscopy and optical reflectometry. Second, the chemical composition of the native oxide film was determined by XPS, and the results related with the micro‐electrochemical experiments. The work shows a strong effect of the basal orientation on the electrochemical behavior. During anodic oxidation, strong electron transfer reactions occur at this orientation, while the enhanced conductivity of the oxide film is also proved by electrochemical impedance spectroscopy. Moreover, a non‐highfield conformal oxide growth and crystallization was observed on the basal plane. These effects, especially the electron conductivity, is related to the incorporation of alloying elements in the passive film.

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Enhancement of pure titanium localized corrosion resistance by anodic oxidation

Cited by 19 publications

References 32 publications

Corrosion resistance enhancement of chemically oxidized titanium through NaOH and H₂O₂ exposure

Corrosion resistance enhancement of chemically oxidized titanium through NaOH and H₂O₂ exposure

Chemical oxidation as repairing technique to restore corrosion resistance on damaged anodized titanium

Micro‐electrochemical investigation of the passive behavior of thin anodic titanium oxide films on TiAlV6‐4

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Enhancement of pure titanium localized corrosion resistance by anodic oxidation

Cited by 19 publications

References 32 publications

Corrosion resistance enhancement of chemically oxidized titanium through NaOH and H2O2 exposure

Corrosion resistance enhancement of chemically oxidized titanium through NaOH and H2O2 exposure

Chemical oxidation as repairing technique to restore corrosion resistance on damaged anodized titanium

Micro‐electrochemical investigation of the passive behavior of thin anodic titanium oxide films on TiAlV6‐4

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Corrosion resistance enhancement of chemically oxidized titanium through NaOH and H₂O₂ exposure

Corrosion resistance enhancement of chemically oxidized titanium through NaOH and H₂O₂ exposure