Abstract
Refractory metals and alloys have excellent corrosion resistance to pure alkali metals; however, this inherent corrosion resistance is adversely affected by small amounts of oxygen.
SNAP-8 boilers under evaluation employ NaK in a thermal bond annulus. This NaK contacts both tantalum tubing and weldments and it is therefore important to determine the effect of the oxygen concentration of tantalum on its corrosion resistance to NaK.
Tantalum specimens with homogeneous oxygen concentrations ranging from 50–500 ppm were prepared by contamination at low pressure and subsequently exposed to NaK at 1350°F for 1000 hours to determine the threshold oxygen concentration for corrosion. Additional contaminated and uncontaminated specimens were welded in pure helium and helium contaminated with air to evaluate the combined effects of welding, welding gas purity, and pre-weld oxygen concentration of the tantalum on the corrosion resistance of the tantalum to NaK. Some specimens were also exposed at 1200°F for 100 hours to determine the effects of temperature and time on corrosion.
The effects of the exposure to NaK were evaluated by weight change measurements, bend tests, metallographic examinations, micro-hardness measurements, and chemical analysis.
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© 1970 Springer Science+Business Media New York
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Harrison, R.W. (1970). Corrosion of Oxygen Contaminated Tantalum in NaK. In: Draley, J.E., Weeks, J.R. (eds) Corrosion by Liquid Metals. Springer, Boston, MA. https://doi.org/10.1007/978-1-4684-1845-3_10
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DOI: https://doi.org/10.1007/978-1-4684-1845-3_10
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4684-1847-7
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