Abstract
By rapid solid-state reactions, materials with formula Zr1-xHf xW2O8 solid solutions have been successfully synthesized and their structures and phase transitions have been studied. The appropriate temperature and sintering time are 1573 K and 30~60 min, respectively. Compared with traditional Solid Phase Reaction methods,this rapid synthetic method simplifies the production process and reduces the sintering time and energy consumption greatly. Powder XRD and Raman spectroscopic analyses reveal that the Zr1-xHf xW2O8 solid solutions are cubic ZrW2O8 type in crystal structure at room temperature. Substitutions using equivalent alter the properties of ZrW2O8 such as cell parameters, order-disorder phase transformation temperatures and thermal stability. Temperature dependent Raman spectroscopic studies demonstrate that the order–disorder phase transition temperature increases with increasing the content of Hf and not only the librational motion of
the WO 4 tetrahedra and the Z rO 6 /HfO 6 octahedra but also the correlated motions of transilation and libration with the
asymmetric stretching vibrations of the polyhedra are responsible for the negative thermal expansion in the low temperature
phase.
Keywords
Rapid solid-state reaction, Solid solutions, Negative thermal expansion, Raman spectroscopy.
Citation
X. Y. GUO, Y. S. ZHANG, C. X. CHENG, Raman spectroscopic s tudy of Zr 1 x Hf x W 2 O 8 solid solutions by rapid solid state reactions, Optoelectronics and Advanced Materials - Rapid Communications, 9, 5-6, May-June 2015, pp.750-753 (2015).
Submitted at: Dec. 13, 2013
Accepted at: May 7, 2015