The hot corrosion behaviour of the γ-Y 2 Si 2 O 7 ceramic exposed to NaVO 3 or V 2 O 5 molten salt was studied at 1000-1300°C. YVO 4 was identified as the corrosion product due to the chemical interaction of the two corrosive agents with the γ-Y 2 Si 2 O 7 ceramic. Although YVO 4 produced in the two corrosion reactions had the same crystallographic structure, they had different morphologies. YVO 4 produced by the corrosion of NaVO 3 with the γ-Y 2 Si 2 O 7 ceramic showed a rod-like shape, whereas it was particle-shaped in the corrosion reaction of V 2 O 5 with the γ-Y 2 Si 2 O 7 ceramic. Additionally, the degradation of γ-Y 2 Si 2 O 7 ceramic by V 2 O 5 was more severe than that by NaVO 3 , and the thickness of the corrosion layer significantly increased with temperature. In this study, a model describing the formation of the corrosion product was established, and the formation of YVO 4 with different morphologies in the two corrosion reactions was explained based on the growth characteristics of the YVO 4 crystals. K E Y W O R D S corrosion mechanism, hot corrosion, microstructure, molten salts, γ-Y 2 Si 2 O 7