Complementary Raman and ToF-SIMS analysis of oxide and fluoride networks in LiF corrosion of Inconel 625

Artikel i vetenskaplig tidskrift, 2027

This study investigates the corrosion scale formed on Inconel 625 exposed to LiF in air at 600°C for 168 h and 1000 h, using confocal Raman imaging in combination with SEM-EDS, ToF-SIMS, and XRD. Raman imaging enabled spatially resolved identification of the oxide scale, revealing a multilayered structure consisting of outer lithiated (Li,Fe-doped) NiO, Ni(Fe,Cr)2O4 spinels, CrNbO4, Cr2O3 and an innermost MoO2. LiCrO2 was detected at the interface between a spinel zone and chromia, whereas it was not detected after 168 h, consistent with more extensive lithiation of the inner oxide scale after longer exposure duration. ToF-SIMS complemented the Raman data by unravelling the intergranular metal fluoride activation, transportation towards the metal oxide interface and incorporation into the oxide scales. Raman and ToF-SIMS prove to be complementary, the former resolving the oxide and lithiated phases while the latter is better for detecting the ionic metal fluorides and lithium ion.