Synthesis of nanocrystalline solid solutions based on zirconia and hafnia

Nanosized (2-8 nm) amorphous powders of the solid solution based on zirconia and hafnia are synthesized through back coprecipitation upon treatment of gels at temperatures from +20 to -77 degrees C. Heat treatment of these powders at temperatures up to 1000 and above 1100 degrees C leads to the formation of cubic (fluorite type, O(h)(5)supercript stop = Fm3m) and tetragonal phases of the Zr82Hf10Y3Ce5O (x) composition, respectively. It is revealed that a decrease in the synthesis temperature (from +20 degrees C to -6 degrees C) results in a decrease in the size of gel agglomerates from 30 to 1 mu m. Recrystallization processes in the gels prepared using cryochemical treatment are developed very slowly in the temperature range 500-1200 degrees C (the crystallite size does not exceed 25 nm).