Molten salt corrosion of high density graphite and partially stabilized zirconia coated high density graphite in molten LiCl–KCl salt

Corrosion studies were performed on uncoated high density graphite and plasma sprayed partially stabilized zirconia (PSZ) coated high density graphite with NiCrAlY bond coat in molten LiCl–KCl eutectic salt at 600 °C for periods of 250 h, 1000 h and 2000 h under inert argon atmosphere. High density graphite showed weight loss while PSZ coated high density graphite showed weight gain. There is no significant attack and degradation of top PSZ coating in molten salt, however microcracks were observed at the bond coat-substrate interface after 2000 h of exposure. PSZ coated high density graphite exhibited excellent corrosion resistance in molten LiCl–KCl salt due to chemical stability and absence of phase transformation as confirmed from scanning electron microscopy, X-ray diffraction and laser Raman studies, however adhesion of the coating has to be improved.