| 摘要 |
A ceramic article is described having good fracture toughness comprising substantially spherical ceramic particles, which may be a ceramic oxide such as zirconia or zirconia combined with yttrium oxide. The ceramic particles are compacted and sintered to a density greater than 90 percent of theoretical density. The article is characterized by a substantially uniform chemical composition and a substantially inclusion-free, homogeneous microstructure, which may be a metastable crystalline phase with less than 10 volume percent monoclinic crystalline phase. The article is produced by dissolving, such as in water, a soluble compound containing a metal, e.g. zirconium, to form a solution. A precipitation agent, such as sodium hydroxide or ammonium hydroxide, is combined with the solution to precipitate a hydrophilic colloid of the metal hydroxide, such as zirconium hydroxide. The precipitate is formed into particles which are rapidly solidified while preventing agglomeration thereof. The particles are dried, compressed to increase density and reduce size, calcined to convert the metal hydroxide to oxide, e.g. zirconium oxide, and then the particles are compacted and sintered to form a dense ceramic article. |
