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中国物理学会期刊

非晶和纳米ZrO2·Y2O3(15%)的X射线衍射与扩展X射线吸收精细结构研究

CSTR: 32037.14.aps.50.1318

AMORPHOUS AND NANOCRYSTALLINE ZrO2·Y2O3(15%) STUDIED BY EXTENDED X-RAY ABSORPTION FINE STRUCTURE

CSTR: 32037.14.aps.50.1318
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  • 利用粉末X射线衍射和扩展X射线吸收精细结构(EXAFS)技术对用化学共沉淀法制备的非晶和纳米ZrO2·15%Y2O3体系进行了研究.粉末X射线衍射结果表明,300℃温度处理的样品呈非晶态,500℃时样品已经晶化,形成单一立方相的纳米结构.EXAFS分析显示,在从非晶态向纳米结构晶化的过程中,最近邻的ZrO配位层的配位数和键长没有发生明显的改变,说明300℃时已经形成和900℃相同的最近邻局域结构.而对于ZrZr(Y)配位层,随着晶粒尺寸的减

     

    Chemical coprecipitated amorphous and nanocrystalline ZrO2·Y2O3(15%) was studied by Powder X-ray diffraction(XRD) and extended X-ray absorption fine structure(EXAFS). XRD result shows that the sample is an amorphous phase annealed below 300℃; and it crystallizes into cubic nanocrystalline zirconia at 500℃. EXAFS analysis indicates that the coordination number and bond length of Zr-O shell has not changed when transforming from amorphous into nanocrystalline. This suggests that at 300℃,it has formed the same nearest-neighbor local structure as at 900℃. For Zr-Zr(Y) shell, with the reducing of grain size, the coordination number decreases obviously: the bond length is shorter and the disorder becomes larger. This result suggests that the grain size effect is much stronger for more distant coordination shell (Zr-Zr ) than for the first nearest-neighbor shell(Zr-O).

     

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