CHARACTERIZATION AND SINTERING OF REACTIVE CERIUM(IV) OXIDE POWDERS PREPARED BY THE HYDRAZINE METHOD

Nanocrystalline cerium(IV) oxide (CeO2) powders have been prepared by adding hydrazine monohydrate to an aqueous solution of hydrous cerium nitrate (Ce(NO3)(3) . 6H(2)O), followed by mashing and drying. The lat tice parameter of the as-prepared powder is a = 0.5415 nm. The powder characteristics and sinterability of reactive CeO2 have been studied. The surface areas of powders that have been heated at low temperatures are high, and these surface areas do not decrease to 10 m(2)/g until the temperature is >1200 degrees C. Crystallite size and particle size are strongly dependent on the heating temperature. Optimum sintered d ensities are obtained by calcining in the temperature range of 700 deg rees-800 degrees C. Ceramics with almost-full density can be fabricate d at a temperature as low as 1150 degrees C.