Corrosion Behavior of Nb-Containing Fecral Alloy in High Temperature Borated and Lithiated Solution: The Preferential Intergranular Oxidation

Abstract

An investigation into the corrosion characteristics of a Nb-containing FeCrAl alloy in a high-temperature aqueous solution comprising lithium hydroxide and boric acid was conducted. After 745 hours of corrosion exposure, observations revealed the existence of grain boundary cracks and preferential oxidation, and the transformation from spinel oxide to amorphous oxide at the grain boundary was detected. Oxygen-18 corrosion labeling results suggested that the corrosion of the alloy exhibited uniformity within a brief timeframe, indicating that preferential oxidation arose as a consequence of the cumulative effects of corrosion. In conjunction with the findings from VASP calculations, the potential mechanisms are deliberated.

Keywords: FeCrAl alloy, oxygen-18 isotope, crack, amorphous oxide, calculation