Preparation and Characterization of Ceria Stabilized Tetragonal Zirconia Polycrystals(I) : Effect of CeO2 Contents on the Mechanical Properties of Ce-TZP

Abstract

The usual ceramic process of mixing and milling in state of oxides <TEX>$ZrO_2$</TEX> and <TEX>$CeO_2$</TEX> was adopted in this study in a wet process to manufacture Ce-TZP. <TEX>$CeO_2$</TEX>-<TEX>$ZrO_2$</TEX> ceramics containing 8~20 mol% <TEX>$CeO_2$</TEX> were made by heat treatment at <TEX>$1250\sim1500^{\circ}C$</TEX> for 5hr. The maximum dispersion point of every slurry manufactured with a mixture of <TEX>$ZrO_2$</TEX> and <TEX>$CeO_2$</TEX> was neat at pH10. A stable slurry with average particle size of 90 nm can be manufactured when it is dispersed with the use of ammonia water and polycarboxylic acid ammonium. The sintered Ce-TZP ceramics manufactured with the addition of <TEX>$CeO_2$</TEX> in a concentration of less than 10 mol% progressed to the fracture of the specimen due to the existence of a monoclinic phase of more than 30% at room temperature. More than 99% of the tetragonal phase was created for the sintered body with the addition of <TEX>$CeO_2$</TEX> beyond 18 mol%, but the degradation of the mechanical properties on the entire specimen was brought about due to the <TEX>$CeO_2$</TEX> existing in a percentage above 3%. Consequently, the optimal Ce-TZP level combined in the oxide state was identified to be 16 mol% of <TEX>$CeO_2$</TEX> contents.