Effect of CrCl2 or VCl2 addition on corrosion of Cr metal in molten MgCl2-KCl

This study investigated the effects of adding 1 wt% CrCl 2 and VCl 2 on Cr corrosion in eutectic MgCl 2 -KCl at 773 K under an argon atmosphere, using electrochemistry and immersion experiments. The redox potential of V 3+ /V 2+ was more negative than Cr 2+ /Cr, suggesting that V 2+ can protect Cr from dissolution. Additionally, the morphological and chemical evolutions investigated with scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDS), and electron energy loss spectroscopy (EELS) confirmed the corrosion protection mechanism of adding CrCl 2 and VCl 2 . These findings are crucial for further improving the stability of containment alloys in molten salt applications. • CrCl 2 and VCl 2 additives effectively protect Cr metal from corrosion in molten MgCl 2 -KCl. • V2+ is preferentially oxidized over Cr 2+ , providing cathodic protection for Cr. • STEM, EDS, and EELS analyses confirm MgO and Cr 2 O 3 as corrosion products on Cr surfaces. • EELS analysis shows that Cr 3+ and V 3+ in the salt are due to oxidation of CrCl 2 and VCl 2 additives by impurities.