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Influence of fluoride and chromium(VI) ions on corrosion mechanisms of Pb-3wt%sn-0.5wt%Ag anode

Journal Article


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Abstract


  • A mix solution of fluorine and chromium ions (Cr-F solution) for applications in chromium plating field has a characteristic of strong corrosion and oxidation, promoting lead alloys anode degraded rapidly. The present study explores the time dependence on corrosion mechanisms of lead alloys anode oxidised in Cr-F solution under conditions of high current density. Scanning electron microscopy (SEM) with an energy dispersive X-ray spectroscopy (EDX) shows a double-layer oxide film is electrochemically developed on lead alloys anode after oxidation for above 0.5h. The outer layer is primarily PbO and PbO2, and the inner layer contains PbCrO4 and PbF2, followed by PbO. In the initial oxidation stage (oxidation time below 60s) of lead alloys anode, the Raman peaks of PbCrO4 and PbF2 are clearly shown by the Raman spectrascanning. With increasing reaction time, Raman peaks intensity for PbO is strengthened. Cyclic voltammetry reveals thateffect of fluorine ions on the electrode potential for lead alloys anode change among Pb, PbO, PbCrO4, PbO1+x (0<x<1) and β-PbO2. After oxidation treatment, electrochemical impedance spectroscopy (EIS) in 3g/L NH4F and/or 170g/L CrO3 solution indicates greater charge transfer resistance (Rt) for samples of longer oxidation time up until 2h. The corrosionmechanisms of the anode reaction at the anode/solution interface are discussed using the experimental results.

Authors


  •   Li, Jianzhong (external author)
  •   Dr X Sun, X (external author)
  •   Tian, Yanwen (external author)
  •   Zhao, Yue

Publication Date


  • 2013

Citation


  • Li, J., Sun, X., Tian, Y. & Zhao, Y. (2013). Influence of fluoride and chromium(VI) ions on corrosion mechanisms of Pb-3wt%sn-0.5wt%Ag anode. International Journal of Electrochemical Science, 8 (5), 6553-6565.

Scopus Eid


  • 2-s2.0-84878695937

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2559&context=eispapers

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/1550

Number Of Pages


  • 12

Start Page


  • 6553

End Page


  • 6565

Volume


  • 8

Issue


  • 5

Place Of Publication


  • http://www.electrochemsci.org/papers/vol8/80506553.pdf

Abstract


  • A mix solution of fluorine and chromium ions (Cr-F solution) for applications in chromium plating field has a characteristic of strong corrosion and oxidation, promoting lead alloys anode degraded rapidly. The present study explores the time dependence on corrosion mechanisms of lead alloys anode oxidised in Cr-F solution under conditions of high current density. Scanning electron microscopy (SEM) with an energy dispersive X-ray spectroscopy (EDX) shows a double-layer oxide film is electrochemically developed on lead alloys anode after oxidation for above 0.5h. The outer layer is primarily PbO and PbO2, and the inner layer contains PbCrO4 and PbF2, followed by PbO. In the initial oxidation stage (oxidation time below 60s) of lead alloys anode, the Raman peaks of PbCrO4 and PbF2 are clearly shown by the Raman spectrascanning. With increasing reaction time, Raman peaks intensity for PbO is strengthened. Cyclic voltammetry reveals thateffect of fluorine ions on the electrode potential for lead alloys anode change among Pb, PbO, PbCrO4, PbO1+x (0<x<1) and β-PbO2. After oxidation treatment, electrochemical impedance spectroscopy (EIS) in 3g/L NH4F and/or 170g/L CrO3 solution indicates greater charge transfer resistance (Rt) for samples of longer oxidation time up until 2h. The corrosionmechanisms of the anode reaction at the anode/solution interface are discussed using the experimental results.

Authors


  •   Li, Jianzhong (external author)
  •   Dr X Sun, X (external author)
  •   Tian, Yanwen (external author)
  •   Zhao, Yue

Publication Date


  • 2013

Citation


  • Li, J., Sun, X., Tian, Y. & Zhao, Y. (2013). Influence of fluoride and chromium(VI) ions on corrosion mechanisms of Pb-3wt%sn-0.5wt%Ag anode. International Journal of Electrochemical Science, 8 (5), 6553-6565.

Scopus Eid


  • 2-s2.0-84878695937

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2559&context=eispapers

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/1550

Number Of Pages


  • 12

Start Page


  • 6553

End Page


  • 6565

Volume


  • 8

Issue


  • 5

Place Of Publication


  • http://www.electrochemsci.org/papers/vol8/80506553.pdf