Stable/Metastable Ce-TZP, effect of Chemical Composition and Preparation Method

Ceria doped tetragonal zirconia polycrystals Ce-TZP could be prepared with a high percent of metastable tetragonal phase. The material prepared by the coprecipitation technique is of higher toughness and more sinterability than the the materials prepared by the mechanical mixing method. A toughness up to 31 MPa √ m was obtained for the sintered samples made from the coprecipitated powders, containing 12 mole% ceria and fired at 1500 degree C. The fracture surface of these samples contained about 80% monoclinic phase, while the material prepared from the coprecipitated powder of 17.4 mole% Ce O2 contains only a stable tetragonal phase and has a KIC of 4.6 MPa √ m. Four point bend strength from 390 up to 560 MPa have been obtained depending on the composition. Compacts made from the hydrothermally treated powders had be calcined in order to be sintered to high densities. Differences in the properties of the materials prepared from commercial powders depend largely on the additives of the trivalent rare earth oxides as well as the ceria content itself. 11 figs