Synthesis and negative thermal expansion properties of solid solutions Yb_{2鈭?span style='font-style: italic'>x}La_xW₃O₁₂ (0 鈮?#xa0;x 鈮?#xa0;2)

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• 作者：Hongfei Liu^a ; ^{liuhf@yzu.edu.cn} ; Wei Zhang^a ; Zhiping Zhang^b ; Xiaobing Chen^a
• 关键词：C. Thermal expansion ; Solid solution ; Tungstates
• 刊名：Ceramics International
• 出版年：2012
• 期刊代码：13_02728842
• 类别：ms
• 出版时间：May, 2012
• 卷：38
• 期：4
• 页码：2951-2956
• 文件大小：1179 K

摘要

A new series of rare earth solid solutions Yb_2鈭?em>xLa_xW₃O₁₂ were successfully synthesized by the solid-state method. Effects of substituted ion lanthanum on the microstructures and thermal expansion properties in the resulting Yb_2鈭?em>xLa_xW₃O₁₂ ceramics were investigated by X-ray diffraction (XRD), thermogravimetric analyzer (TGA), field emission scanning electron microscope (FESEM) and thermal mechanical analyzer (TMA). Results indicate that the structural phase transition of the Yb_2鈭?em>xLa_xW₃O₁₂ changes from orthorhombic to monoclinic with increasing substituted content of lanthanum. The pure phases can form in the composition range of 0&#xA0;鈮?#xA0;x < 0.5 with orthorhombic structure and 1.5 < x 鈮?#xA0;2 with monoclinic one. High lanthanum content leads to a low hygroscopicity of Yb_2鈭?em>xLa_xW₃O₁₂. Negative thermal coefficients of the Yb_2鈭?em>xLa_xW₃O₁₂ (0 鈮?#xA0;x 鈮?#xA0;2) also vary from 鈭?.78 脳 10^鈭? K^鈭? to 2.06 脳 10^鈭? K^鈭? with increasing substituted content of lanthanum.