Crystal defects and phase transitions of nanocrystalline yttria-stabilised zirconia induced by high-energy ball milling
Crystal defects and phase transitions of nanocrystalline yttria-stabilised zirconia induced by high-energy ball milling
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DOI：
10.1016/j.ceramint.2020.11.044
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发表时间：
2020-11
影响因子：
5.2
通讯作者：
Zhang Jianxing;Feng Zongyu;Song Jianhui;Zhangbin He;Yang Juanyu;W. Ning;Chen‐gao Fang;Duo Lei
中科院分区：
文献类型：
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作者：
Zhang Jianxing;Feng Zongyu;Song Jianhui;Zhangbin He;Yang Juanyu;W. Ning;Chen‐gao Fang;Duo Lei
氧化钇稳定的氧化锆（YSZ）是一种很有前途的固体氧化物燃料电池（SOFC）和气体传感器的电解质。采用高能球磨法将共沉淀法制备的5mol%氧化钇稳定氧化锆（5 YSZ）粉末的粒径从10.47 μm细化到130 nm，以提高其烧结性和离子导电性。球磨过程将5 YSZ粉末的比表面积从约11 m2 g-1增加到22 m2 g-1。透射电子显微镜（TEM）和高分辨透射电子显微镜（HRTEM）的结果表明，5 YSZ微晶分解成不规则的形状与点，线，和平面缺陷的演变。在研磨时间的增加增加的5 YSZ粉末中的氧缺陷的数量，所揭示的X-射线光电子能谱的结果。通过X射线衍射、拉曼光谱、高分辨透射电镜和选区电子衍射分析研究了粉末中四方相到单斜相的转变。球磨后的粉体易于致密化，但存在较多的晶体缺陷和大量的them-ZrO 2相不利于粉体的进一步致密化。尽管在本研究中使用了高烧结温度（1500 °C），但是对于在1500 rpm的转子速度下球磨60 min的粉末，可以实现99.67%的最大相对密度。此外，在高能球磨过程之后，5 YSZ的离子电导率从20.6 mS cm-1（850 °C）显著提高到36.2 mS cm-1。
Yttria-stabilised zirconia (YSZ) is a promising electrolyte for SOFCs and gas sensors. In this study, the particle size of a co-precipitated 5 mol% yttria-stabilised zirconia (5 YSZ) powder was refined from 10.47 μm to 130 nm via high-energy ball milling to improve its sinterability and ionic conductivity. The ball milling process increased the specific surface area of the 5 YSZ powder from approximately 11 to 22 m2g−1. The transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) results indicated that the 5 YSZ crystallites decomposed into irregular shapes with the evolution of point, linear, and planar defects. An increase in the milling duration increased the number of oxygen defects in the 5 YSZ powder, as revealed by the X-ray photoelectron spectroscopy results. The tetragonal-to-monoclinic phase transformation occurring in the powder was investigated by X-ray diffraction, Raman spectroscopy, HRTEM, and selected-area electron diffraction pattern analyses. The ball-milled powders could be easily densified, but the presence of too many crystal defects and the large fraction of them-ZrO2phase were detrimental to the further densification of the 5 YSZ powders. In spite of the high sintering temperature (1500 °C) used in this study, the maximum relative density of 99.67% could be achieved for the powder ball-milled for 60 min at the rotor speed of 1500 rpm. Moreover, the ionic conductivity of 5 YSZ was improved significantly from 20.6 to 36.2 mS cm−1(850 °C) after the high-energy ball milling process.