[en] Full text: CeO₂ solid solutions containing trivalent rare earth cations are promising materials for Intermediate Temperature Solid Oxide Fuel Cells. CeO₂ -TR₂O₃ solid solutions (TR = Sm, Gd and Eu) depict ionic conductivity at 800 °C similar to that of YSZ at 1000 °C (σ = 0.15 S.cm^-1) [1] . By reducing the particle size of the starting powders down to nanosize range and controlling the grain size of the sintered electrolytes it is possible to further improve the ionic conductivity of the material in addition to grant high final density and mechanical strength, important for electrolyte supported cells. Therefore, the objective of the present study was to study an alternative sintering route to inhibit the grain growth of dense Ce_0.9Gd_{0.1 1.95}, Ce_0.8Gd_0.2O_1.90 and Ce_0.7Gd_0.3O_1.85 powders previously synthesized by microwave-assisted hydrothermal method. The solid solutions were characterized by TG/DTA, XRD, particle size analyses and SEM. The results revealed that single phase fluorite structured CeO₂ -TR₂O₃ solid solution nanocrystallites were formed. The possibility of obtaining oxides in the nanometric scale by polymer precursor synthesis involves low energy and short synthesis time in the production of powders with excellent properties for the intended aforementioned applications. (author)