Single Crystal and Sintered Alumina Corrosion in Liquid Sodium

Abstract

Corrosion tests are achieved in static conditions at 450 and 550 °C for various oxygen contents and durations with single crystal and sintered alumina regarded as model materials for ceramics. Extremely pure and dense sintered alumina presents no intergranular corrosion and identical behavior as single crystal. Corrosion appears to proceed by reaction of Al2O3 with dissolved oxygen (Na2O) to form sodium aluminate (NaAlO2). Then, sodium aluminate is dissolved in liquid sodium upon a mechanism still to be elucidated. The corrosion morphology is equivalent to dissolution. From weight loss measurement, linear kinetics is found with a constant dissolution rate of (61 ± 2).10 -4 mg.dm -2 .h -1 at 550°C and low oxygen content (<1 ppm). No significant corrosion rate could be measured at 450°C and low oxygen content. An order reaction kinetics with respect to dissolved oxygen content of 0.6 ± 0.2 is found.

Further insights into the mechanisms involved in the corrosion of 316L(N) austenitic steel in oxygenated liquid sodium at 550 °C

“…The corrosion tests were performed in a static sodium device [33,[39][40][41]. The stainless steel samples are immersed in sodium (approximately 2.3 kg), contained in a molybdenum crucible.…”