| 摘要 |
Coagulated particles of ultrafine monoclinic zicronia crystals oriented in fiber bundle-like form, wherein primary particles of ultrafine monoclinic zirconia are oriented to join and extended in the direction of C-axis into fine fibrous form of less than 50 ANGSTROM diameter and they are further gathered into a bundle-like form having from 300 to 2000 ANGSTROM of width and from 2000 to 10000 ANGSTROM of length. Such particles are prepared by hydrothermal processing which is applied at a temperature from 120 DEG to 300 DEG C. to an acidic aqueous solution containing a water-soluble zirconium compound in an amount of from 0.1 to 2.0 mol/l as Zr, SO42- in an amount of from 0.2 to 2.0 mol/l and a water-soluble compound selected from the group consisting of water-soluble magnesium compounds, water-soluble ammonium compounds and mixtures thereof in an amount of from 0.05 to 1.5 mol/l as Mg2+ or NH4. |
