Impact of liquid sodium corrosion on microstructure and electrical properties of yttrium-doped thoria prepared by co-precipitation

Impact of impurities on the fabrication and performances of yttrium-doped thoria electrolyte ceramics

“…2.8 and 5.5 wt.% in yttrium, respectively), independently from the microstructure [3,7]. Finally, the ceramics were found to be durable during corrosion tests in liquid sodium, even for penalizing oxygen concentration up to 70-80 ppm [8]. All these results showed that yttrium-doped thoria could be an excellent candidate for oxygen sensors to be used in liquid sodium.…”

“…This particular composition (i.e. Th0.85Y0.15O1.925, hereafter considered as the reference sample free from impurities, and designed as pure sample) was chosen as it was generally correlated to a maximum in the ionic conductivity of the ceramic [3,8]. Zr, Al or Si were then introduced at three different concentrations, i.e.…”

“…Additional details regarding the preparation of the samples have been described in our previous publications [8]. The Nyquist diagrams collected were fitted with the ZView software (Scribner Associates Incorporated).…”

“…This setup was placed in an oven at 773 K during 500 hours in order to perform the corrosion tests. Afterwards, the pellets were recovered from the liquid sodium, and washed with ultrapure ethanol before characterization [8].…”

“…In order to evaluate the impact of impurities on the electrical properties of Th0.85Y0.15O1.925, impedance spectroscopy measurements were undertaken on samples doped with silicon and/or zirconium, using the protocol previously employed for pure samples [8].…”