In order to synthesize t-ZrO
2 containing TiO
2 as a stabilizing agent, two kinds of ZrO
2 precursors were prepared by coprecipitation method. One was TiO
2-ZrO
2 system with the compositions of 5∼20mol% of TiO
2 and the other was CeO
2-TiO
2-ZrO
2 system with the compositions of total 20mol% of TiO
2 and CeO
2. Synthesized precursors were calcined at 800°C and then sintered at 1450°C for 3h. In the binary system, t-ZrO
2 phase was observed in calcined powders at any content of TiO
2. Formation of t-ZrO
2 increased with increasing addition of TiO
2, and the calcined powder with 18mol% TiO
2 was composed of only tetragonal phase at room temperature. For the sintered bodies of the calcined powders, however, t-ZrO
2 phase could not be retained, regardless of TiO
2 content. For 5∼10mol% TiO
2, they are composed of only m-ZrO
2 phase, and for 15∼20mol% TiO
2, m-ZrO
2/ZrTiO
4 composites were obtained. Tetragonal zirconia polycrystal (TZP) could not be obtained. In the ternary system, t-ZrO
2 phase was also obtained by calcination of precursors at any content of TiO
2 and CeO
2. The sintered body consisted of only t-ZrO
2 phase by using the powder with 10mol% TiO
2 and 10mol% CeO
2. The polycrystal has the relative density of approximately 98%.
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