Effect of dispersed oxide of cerium, lanthanum and thorium on the corrosion behaviour of tungsten in 3.5 wt-% NaCl solution

ABSTRACT

Tungsten has unique physical and chemical properties that make it ideal for high-temperature applications. At room temperature, it is being considered for medical applications due to its protection by an oxide/hydroxide film. However, breakdown of the oxide film and tungsten dissolution can have adverse effects on human health. This study investigates the corrosion of tungsten with and without dispersed oxides of rare-earth elements (ThO₂, CeO₂, and La₂O₃) in a 3 wt-% NaCl solution using electrochemical techniques. The results suggest that tungsten dissolution occurs after the formation of an oxide film, likely WO₃, on the surface of tungsten and dispersed oxide tungsten. La₂O₃ and CeO₂ may decrease the corrosion rate of tungsten, while WThO₂/tungsten has similar corrosion rates to tungsten. The study concludes that CeO₂ or La₂O₃ could replace ThO₂ in tungsten due to the radioactive nature of Th.

KEYWORDS:

• Rare-earth elements
• corrosion
• tungsten
• NaCl solution

Acknowledgements

The authors would like to express their gratitude to the CONACYT for providing the equipment necessary to carry out the present study through the infrastructure project under grant 205050. They would also like to thank the National Laboratory for the Study of Nano and Biomaterials (LANNBIO) at CINVESTAV-Mérida for their support. The authors would also like to thank Ing. Gualdemar Casanova for his assistance in the metallographic preparation of the samples.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

ETV would like to acknowledge the CONACYT/MEXICO for her postdoctoral fellowship (BP-PA-20220718214010901-2840985). MAA acknowledges the support of the National Science Foundation, NSF-2108462 grant for support of his research contribution.