QUESTION :

What are the possible reasons to increase or decrease the ionic conductivity of rare earth doped ceria with sintering temperature?

Lattice parameter and particle size increases with sintering temperature

Dear Colleague,

I am sorry but I have not experience on the ionic conductivity of rare earth doped ceria with sintering temperature , so I cannot help You.

Sorry 

sincerely Yours

Giuseppe Daurelio

Thanks Mr. Daurelio for your communication 

If the atomis radius of the rare earth element is larger than Ce, then lattice parameter increase indicates that solid solutions form with increased amount of Re atoms.

The increased grain size with temperature, on the one hand, is due to the rapid grain growth at higher temperatures, on the other hand, is due to the increased diffusivity with the increase of dopant content.

From defect chemistry point of view, dopant with lower valence charge like Y+3, La+3 etc will increase the concentration of oxygen vacacy in CeO2 so that the ionic conductivity wil increase. You can try to write the defect chemistry equations.

Thank you Mr. Y. Zhou for very nice explanation...it will helps me a lot

Thanks Mr. Hajalilou