Sintering and microstructural studies in the system ZrO2 · TiO2 · CeO2

Tetragonal zirconia polycrystals (TZP) in the system ZrO₂ · TiO₂ · CeO₂ have been prepared from titanium and zirconium alkoxides and cerium nitrate precursors. The change in microstructure with sintering temperature in the range 1300 to 1600° C has been characterized. A fully tetragonal structure with theoretical final density has been achieved after liquid-phase sintering in the range 1350 to 1400° C for 2h. Sintering at temperatures above 1450° C resulted in a loss of stabilizer from the matrix, by the formation of zirconium titanate and to a cerium-, titanium-rich liquid. The loss of stabilizer was such that in the temperature range 1500 to 1600° C, extensive transformation to monoclinic zirconia occurred spontaneously on cooling. The tetragonal zirconia formed after sintering at 1350° C was found to be very stable. Thec/a ratio of the tetragonal phase in this system is higher than in any of the binary TZP systems reported in the literature. The stability of the tetragonal phase is believed to be associated with this highc/a ratio.