SINTERING OF ZRO2-CEO2 SPHERICAL POWDERS PREPARED BY A WATER EXTRACTION VARIANT OF THE SOL-GEL PROCESS

Spherical powders (with diameters <100 mum) of zirconia-ceria hydroxide gels (stabilized with nitrates or chlorides) were fabricated by a water extraction variant of the sol-gel process. The resulting powders were calcined at 400, 600, and 800-degrees-C in order to obtain crystalline forms, subsequently pressed at various pressures, and then sintered for 8 h at 1700-degrees-C. The sintered pellets had relatively high geometric density (in some cases >95% of the theoretical density) and showed both tetragonal and/or cubic x-ray phases. The bulk density values of these ceria-doped zirconia sintered pellets are much higher than those obtained for the CaO- or Y2O3-doped-zirconia samples prepared by the same process.