| 摘要 |
PURPOSE:To obtain fine zirconium oxide powder having a narrow particle size distribution, high activity and favorable sinterability by freezing zirconium hydroxyde hydrate under ordinary pressure, raising the temp. to remove an excess of water, and carrying out freezing in vacuum and drying by the sublimation of ice. CONSTITUTION:An alkali soln. is added to zirconium oxychloride to form zirconium hydroxide, and this zirconium hydroxide is freezed under ordinary pressure. The freezed matter is allowed to stand at 10-25 deg.C so that it is held at about 0 deg.C, and an excess of water is removed. The water content is adjusted to about 40%. The zirconium hydroxide is then placed in vacuum. It is decomposed into H2O and ZrO2, and freezing proceeds by the vaporization of H2O. The freezed matter is treated again in vacuum to sublime ice. The resulting dried powder has 0.05- 0.003mum small particles size, 120-150m<2>/g large surface area, high activity and favorable sinterability. Conventional powder has 40-70m<2>/g surface area.
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