Effect of the grain size of YSZ ceramic materials on corrosion resistance in a hot molten salt CaCl2-CaF2-CaO system.

• The corrosion resistance of YSZ was investigated in CaCl 2 -CaF 2 -CaO molten salt. • The reactivity between YSZ and molten salt was dependent on grain size. • Chemical attack occurred preferentially at the grain boundaries over YSZ grains. • With increasing grain size, grain boundary area decreased, reducing the attack path. • Larger grain sizes resulted in reduced reaction between YSZ and the molten salt. The hot corrosion behaviour of YSZ specimens sintered at 1500 °C (6 and 11 h) and 1600 °C (11 h) was evaluated in CaCl 2 -CaF 2 -CaO molten salt at 1150 °C. YSZ sintered at 1600 °C for 11 h exhibited the lowest corrosion, whereas YSZ sintered at 1500 °C for 6 h showed the most corrosion, with a grain size dependency. XRD analysis showed that all YSZ contained mainly CaZrO 3 with a small t-ZrO 2 peak. To use SOM anodes for the electrowinning of various metals, the corrosion resistance of YSZ can be improved by adjusting the grain size instead of adding stabilizers. [ABSTRACT FROM AUTHOR]