Microstructure of yttria doped ceria as a function of oxalate co-precipitation synthesis conditions

L. Brissonneau (1) , A. Mathieu (1) , B. Tormos (1)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)

In sodium fast reactors (SFR), dissolved oxygen in sodium can be monitored via potentiometric sensors with an yttria doped thoria electrolyte. Yttria doped ceria (YDC) was chosen as a simulant material to validate the elaboration process of such sensors. The material must exhibit high density and a fine grain microstructure to be resistant to the corrosion by liquid sodium and thermal shocks. Thus, the oxalic coprecipitation route was chosen to avoid milling steps that could bring impurity incorporation which is suspected to induce grain boundary corrosion in sodium. Powder and sintered pellets were analyzed by BET, XRD and SEM. The results show that synthesis conditions are of first importance on the process yield, the oxalate powder microstructure and, eventually, on the ceramic density and microstructure. The impurity content was limited by controlling the synthesis, calcination and sintering steps. Yttrium content influenced the final microstructure in terms of grain size.

Keywords: oxalic precipitation; oxygen sensors; SFR; yttria doped ceria

Domains: Nuclear Experiment [nucl-ex]; Nuclear Theory [nucl-th]

L. Brissonneau, A. Mathieu, B. Tormos. Microstructure of yttria doped ceria as a function of oxalate co-precipitation synthesis conditions. Materials Science and Technology 2015, Oct 2015, Colombus, United States. ⟨10.1007/s40553-016-0087-8⟩. ⟨cea-02509746⟩