Study of Ti{sup 4+} substitution in ZrW{sub 2}O{sub 8} negative thermal expansion materials
- Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281 S-3, B-9000 Ghent (Belgium)
- Faculty of Applied Engineering Sciences, University College Ghent, Schoonmeersstraat 52, B-9000 Ghent (Belgium)
Powder XRD-analysis and thermo-mechanical analysis on sintered TiO{sub 2}-WO{sub 3}-ZrO{sub 2} mixtures revealed the formation of Zr{sub 1-x}Ti{sub x}W{sub 2}O{sub 8} solid solutions. A noticeable decrease in unit cell parameter 'a' and in the order-disorder transition temperature could be seen in the case of Zr{sub 1-x}Ti{sub x}W{sub 2}O{sub 8} solid solutions. Studies performed on other ZrW{sub 2}O{sub 8} solid solutions have attributed an increase in phase transition temperature to a decrease in free lattice volume, whereas a decrease in phase transition temperature was suggested to be due to the presence of a more disordered state. Our studies indicate that the phase transition temperature in our materials is strongly influenced by the bond dissociation energy of the substituting ion-oxygen bond. A decrease in bond strength may compensate for the effect of a decrease in lattice free volume, lowering the phase transition temperature as the degree of substitution by Ti{sup 4+} increases. This hypothesis is proved by differential scanning calorimetry. - Graphical abstract: This study indicates that the phase transition temperature in our materials Zr{sub 1-x}Ti{sub x}W{sub 2}O{sub 8} is strongly influenced by the bond dissociation energy of the substituting ion-oxygen bond. A decrease in bond strength may compensate for the effect of a decrease in lattice-free volume, lowering the phase transition temperature.
- OSTI ID:
- 21043809
- Journal Information:
- Journal of Solid State Chemistry, Vol. 180, Issue 8; Other Information: DOI: 10.1016/j.jssc.2007.05.028; PII: S0022-4596(07)00217-4; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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