ABSTRACT
During thermodynamic measurements on alkali metal carbonates using a galvanic cell, it was found that calcia– and yttria–stabilized zirconia, CSZ and YSZ, respectively, were corroded by the carbonates even in the solid state. Thus, the reactions of CSZ and YSZ with the carbonates were examined at 650–950°C which includes by SEM, EPMA and BEI, and XRD. The carbonates were impregnated along grain boundaries over the entire temperature range. Below the melting temperature, corrosion mainly occurred at the grain boundaries to form alkali metal zirconate, A2CO3 (A = Li, Na and K). The main reaction with the liquid carbonates predominantly proceeded on the surface of the zirconia matrix, and the product was broken away from the surface. Calcium in CSZ was leached into the liquid carbonate phase from the zirconia surface.
