The Passivation Behavior of Sputter-deposited W-Zr Alloys in NaCl and NaOH Solutions

Authors

  • Prakash Shrestha Central Departmenot of Chemistry
  • Jagadeesh Bhattarai Central Departmenot of Chemistry

DOI:

https://doi.org/10.3126/jncs.v25i0.3283

Keywords:

Sputter-deposited W-Zr alloys, Amorphous, Corrosion test, Electrochemical

Abstract

The passivation behavior of the sputter-deposited amorphous or/and nanocrystalline
W-Zr alloys is studied in 0.5 M NaCl and 1 M NaOH solutions at 25°C, open to air using
corrosion tests and electrochemical measurements. Zirconium metal acts synergistically
with tungsten in enhancing the corrosion resistance of the sputter-deposited W-Zr alloys so
as to show lower corrosion rates than those of alloy-constituting elements (that is, tungsten
and zirconium) in 0.5 M NaCl solution. In particular, corrosion rates of the binary W-Zr
alloys containing 23-76 at % zirconium are more than one order of magnitude lower than
that of tungsten (that is, about 0.8-1.1 × 10-3 mm.y-1) and even lower than that of the sputterdeposited
zirconium. On the other hand, the corrosion rates of the W-Zr alloys containing
54-76 at% zirconium are nearly two orders of magnitude lower than that of tungsten and
even about one order of magnitude lower corrosion rate than that of sputter-deposited
zirconium metal in alkaline 1 M NaOH solution. These results clearly revealed that the
simultaneous additions of both tungsten and zirconium metals to the sputter-deposited
amorphous or nanocrystalline W-Zr alloys are effective in enhancing the corrosion
resistance of the alloys in both 0.5 M NaCl and alkaline 1 M NaOH solutions at 25°C, open
to air. The corrosion-resistant of all the examined binary W-Zr alloys in 0.5 M NaCl
solution is higher than in 1 M NaOH solution at 25°C. In general, the open circuit potentials
of all the examined W-Zr alloys are shifted to more noble direction with increasing the alloy
zirconium content in both 0.5 M NaCl and 1 M NaOH solutions.

Keywords: Sputter-deposited W-Zr alloys, amorphous, corrosion test, electrochemical
measurement, NaCl and NaOH solutions.

DOI:  10.3126/jncs.v25i0.3283

Journal of Nepal Chemical Society Volume 25, 2010 pp 37-45

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Author Biographies

Prakash Shrestha, Central Departmenot of Chemistry

Associate Professor, Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal.

Jagadeesh Bhattarai, Central Departmenot of Chemistry

Associate Professor, Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal.

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How to Cite

Shrestha, P., & Bhattarai, J. (2010). The Passivation Behavior of Sputter-deposited W-Zr Alloys in NaCl and NaOH Solutions. Journal of Nepal Chemical Society, 25, 37–45. https://doi.org/10.3126/jncs.v25i0.3283

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