Effect of Surfactant on the Yttria-Stabilized Zirconia Synthesized from Hydrolysis Method

Yttria-stabilized zirconia powder was synthesized by a hydrolysis method using zirconium oxychloride and yttrium chloride as a starting materials. The effect of PEG addition was investigated on the hydrolysis of zirconium oxychloride and characteristics of the obtained yttria-stabilized zirconia powder. By the addition of PEG, the initial hydrolysis of zirconium oxychloride was promoted and the well-dispersed hydrous zirconia powder was obtained. In this case, however, a slight amount of un-reacted zirconium oxychlodride remained even after 115hrs. On the other hand, for the sample without PEG, hydrolysis of starting material was nearly completed after 115hrs but large aggregates of hydrous zirconia were formed. From the results of pH titration, it was found that difference of surface properties of yttria-stabilized zirconia powder prepared with PEG between before and after milling in water was smaller than that of the powder obtained without PEG. Furthermore, the yttria-stabilized zirconia powder containing PEG showed higher content of tetragonal phase than the powder without PEG. These results indicated that zirconium hydroxide as seed particles for hydrolysis reaction was dispersed well by the action of PEG and as a consequence highly dispersion of hydrous zirconia and homogeneous mixing of yttrium hydroxide were achieved.