High-resolution and analytical TEM investigation of metastable-tetragonal phase stabilization in undoped nanocrystalline zirconia
High-resolution and analytical TEM investigation of metastable-tetragonal phase stabilization in undoped nanocrystalline zirconia
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DOI：
10.1166/jnn.2004.110
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发表时间：
2004-09-01
影响因子：
--
通讯作者：
Seal, S
中科院分区：
文献类型：
--
作者：
Oleshko, VR;Howe, JM;Seal, S
采用溶胶-凝胶技术合成了分别具有亚稳四方和四方加单斜晶体结构的亚微米和纳米级纳米晶纯氧化锆（ZrO2）粉末。通过常规和高分辨率透射电子显微镜和场发射分析电子显微镜（包括能量色散 X 射线和电子能量损失光谱）分析沉淀和煅烧 ZrO2 粉末的形态、纳米晶尺寸和结构、聚集趋势、局部电子性质和元素组成。这项研究的结果表明，纳米晶尺寸、应变诱导的晶粒生长限制以及单斜相的同时存在相结合，可以导致未掺杂 ZrO2 中亚稳态四方相的稳定。结果，四方相稳定在尺寸高达 100 nm 的 ZrO2 纳米晶内，这比之前报道的 6 nm 临界尺寸大 16 倍。
Submicron and nano-sized nanocrystalline pure zirconia (ZrO2) powders having metastable tetragonal and tetragonal-plus-monoclinic crystal structures, respectively, were synthesized using the sol-gel technique. The as-precipitated and the calcinated ZrO2 powders were analyzed for their morphology, nanocrystallite size and structures, aggregation tendency, local electronic properties, and elemental compositions by conventional and high-resolution transmission electron microscopy and field-emission analytical electron microscopy, including energy-dispersive X-ray and electron energy-loss spectroscopies. The results from this study indicate that a combination of nanocrystallite size, strain-induced grain-growth confinement, and the simultaneous presence of the monoclinic phase can lead to stabilization of the metastable tetragonal-phase in undoped ZrO2. As a result, the tetragonal phase is stabilized within ZrO2 nanocrystallites up to 100 nm in size, which is 16 times larger than the previously reported critical size of 6 nm.