| 摘要 |
PURPOSE:To provide the titled fine crystal composed of a compound having laminar structure giving an X-ray diffraction pattern wherein some of main diffraction peaks are nearly the same positions as those of tetragonal or cubic ZrO2 and capable of maintaining the above crystal structure by heat-treatment even in the absence of a stabilizer. CONSTITUTION:The objective fine crystal is composed of a compound having laminar structure consisting of metallic ions composed mainly of Zr and anions composed mainly of O and giving an X-ray diffraction pattern wherein some of main diffraction peaks are nearly the same positions as those of tetragonal or cubic ZrO2 and the crystal is extended parallel to the laminar plane and has a thickness of <=200rho. The fine crystal can be produced by heat-treating an acidic aqueous solution of <=2.0pH containing 0.1-1.5g/l of a soluble Zr salt (in terms of Zr) and 0.2-3.0g/l of SO4<2-> ion at 100-300 deg.C and aging the produced flaky fine crystal of ZrO2 containing SO4<2-> ion in a basic aqueous solution to effect the substitution and removal of the SO4<2-> ion. The fine crystal maintains the above crystal structure and keeps its flaky form after a high-temperature heat-treatment at 1,000 deg.C even in the absence of a stabilizer such as Y2O3.
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