| 摘要 |
Sub-micron sized powders of the ceramic metal oxides such as zirconia, alumina, titania, etc. are produced by precipitation from substantially anhydrous solutions of salts of the corresponding metal(s) with substantially anhydrous solutions of alkali metal hydroxides. The precipitates are subsequently washed with water to remove any residual soluble salt and/or solvent, then are dried and usually calcined. The powders thus produced are readily sintered to high density ceramic bodies after conventional pressing into the desired shape. The process is especially suited to the production of zirconia powders, either pure or doped with conventional stabilizing oxides such as yttria. In a typical example, a zirconia powder doped with 5.4% by weight of yttria is prepared by adding a solution of zirconium tetrachloride and yttrium chloride in anhydrous ethanol to a solution of sodium hydroxide in anhydrous ethanol. After washing, drying at 105.degree.C, and calcining at 500.degree.C for two hours, the powder is pressed at 5000 psi into a green body with a density of 1.46 Mg/m3. After one hour of sintering at 1600.degree.C, the fired body has a density of 5.84 Mg/m3, which is 96% of the theoretical maximum. |
