- 作者: Manouchehr Lajavardia,b, Donald J. Kenneya,c and Sheng Hsien Lind
- 中文摘要: The nanocrystalline cubic phase of zirconia was found to be thermally stabilized by the addition of 3 to 40 mol % manganese. The nanocrystalline cubic, tetragonal and monoclinic phases of zirconia stabilized with manganese (III)oxide (Mn-Stabilized Zirconia) were prepared by thermal decomposition of carbonate and hydroxide precursors. Both the crystallization and isothermal phase transitions associated with Mn-SZ were studied using high temperature x-ray diffraction and x-ray diffraction of quenched samples. Cubic Mn-SZ initially crystallized and progressively transformed to tetragonal, and monoclinic structures above 700 °C. The nanocrystalline cubic Mn-SZ containing 25 mol % Mn was found to have the greatest thermal stability, retaining its cubic form at temperatures as high as 800 °C for periods up to 25 hours. Higher than 40 mol %, cubic Mn2O3 was found to coexist with cubic Mn-SZ. The crystallite sizes observed for the cubic, tetragonal and monoclinic Mn-SZ phases ranged from 50 to 137, 130 to 220, and 195 to 450 A respectively, indicating, for ZrO2, that particle size was a primary factor in determining its polymorphs. The classical Avrami equation for nucleation and growth was applied to the observed phase transformations.
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