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

• Published in: Corrosion science Vol. 170; p. 108664
• Main Authors: Kim, Wan-Bae, Kwon, Suk-Cheol, Cho, Soo-Haeng, Lee, Jong-Hyeon
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.07.2020; Elsevier BV
• Subjects: Anode material; Calcium chloride; Calcium fluoride; Calcium zirconate; Corrosion effects; Corrosion resistance; Grain size; Hot corrosion; Hot corrosion behaviour; Molten salts; Sintering; Yttria stabilized zirconia (YSZ); Yttria-stabilized zirconia; Zirconium dioxide; Corrosion resistance; Grain size; Anode material; Hot corrosion behaviour; Yttria stabilized zirconia (YSZ)
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2020.108664

•The corrosion resistance of YSZ was investigated in CaCl2-CaF2-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 CaCl2-CaF2-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 CaZrO3 with a small t-ZrO2 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.