Phase transition, crystal water and low thermal expansion behavior of Al2-2x(ZrMg)(x)W3O12 center dot n(H2O)

作者：Li Fang; Liu Xiansheng; Song Wenbo; Yuan Baohe; Cheng Yongguang; Yuan Huanli; Cheng Fuxing; Chao Mingju; Liang Erjun^*

来源：Journal of Solid State Chemistry, 2014, 218: 15-22.

DOI：10.1016/j.jssc.2014.06.009

• Phase transition
• Low thermal expansion
• Hygroscopicity
• Raman spectroscopy

Al2-2x(ZrMg)(x)W3O12 for 0 <= x <= 1.0 are synthesized to reduce the phase transition temperature of Al2W3O12. It is found that the incorporation of (ZrMg)(6+) into the lattice of Al2W3O12 not only reduces its orthorhombic-to-monoclinic phase transition temperature but also elevates its softening temperature, broadening its applicable temperature range considerably. Al2-2x(ZrMg)(x)W3O12 with x < 0.5 exhibit low coefficients of thermal expansion (CTEs) and non-hygroscopicity, while those for x >= 0.7 are obviously hygroscopic and the CETs decrease with increasing the content of (ZrMg)(6+) so that Al-0.2(ZrMg)(0.9)W3O12 and ZrMgW3O12 exhibit negative thermal expansion. Temperature-dependent Raman spectroscopic study shows the hardening of W-O bonds above 373 K which is attributed to the release of crystal water. The effect of crystal water on the thermal expansion property is discussed based on the hydrogen bond between H in crystal water and electronegative O in Al(ZrMg)-O-W linkages.

• 出版日期2014-10
• 单位郑州大学