| Autor: |
Hui Ma, Xinhua Zhao, Xi Chen, Juzhou Tao, Fuli Guo, Xuebin Deng |
| Rok vydání: |
2012 |
| Předmět: |
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| Zdroj: |
Journal of Alloys and Compounds. 537:227-231 |
| ISSN: |
0925-8388 |
| DOI: |
10.1016/j.jallcom.2012.04.106 |
| Popis: |
A novel cubic ZrW 2− x V x O 8− x /2 solid solution series was found to possess similar negative thermal expansion property like the extensively studied ZrW 2 O 8 . A tetragonal hydrate ZrW 2− x V x O 7− x/ 2 (OH) 2 (H 2 O) 2 up to x = 0.30 was first prepared through acidic steam hydrothermal synthesis, this precursor dehydrates at moderate temperature and converts to an intermediate orthorhombic phase then transforms to corresponding solid solutions at higher temperature. At room temperature cubic ZrW 2− x V x O 8− x /2 ( x = 0–0.24) has α-ZrW 2 O 8 type and ZrW 1.70 V 0.30 O 7.85 has β-ZrW 2 O 8 type disordering. X-ray diffraction, neutron diffraction and Raman spectroscopy studies support an average crystal structure model of ZrW 2− x V x O 8− x /2 as a superposition of respective cubic ZrW 2 O 8 and ZrV 2 O 7 structures. The lattice parameters of cubic ZrW 2− x V x O 8− x /2 solid solutions, the value of orientation order parameter ω and order–disorder phase transition temperature of the solid solutions all decrease with increasing substitution content x . The maximum solid solubility of cubic ZrW 2− x V x O 8− x /2 solid solution reaches 16% according to the Vegard’s law. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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