Study of negative thermal expansion and shift in phase transition temperature in Ti4+- and Sn4+-substituted ZrW2O8 materials |
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Authors: | Buysser Klaartje De Driessche Isabel Van Putte Bart Vande Vanhee Paul Schaubroeck Joseph Hoste Serge |
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Affiliation: | Department of Inorganic and Physical Chemistry, Building S3 Ghent University Krijgslaan 281, 9000 Ghent, Belgium. Klaartje.DeBuysser@Ugent.be |
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Abstract: | The negative-thermal-expansion material ZrW(2)O(8) is known to undergo an order-disorder phase transition which affects its expansion behavior. In this study, Ti(4+) and Sn(4+) are examined as possible substituting ions for the Zr(4+) position in ZrW(2)O(8). This substitution leads to a decrease in cell parameters, as the ionic radii of the substituents are smaller than the Zr(4+) ionic radius. A remarkable decrease in transition temperature is noticed. DSC is used to quantify the enthalpy and entropy changes during the phase transition in order to reveal the mechanisms behind this decrease. It is shown that the strength of the M-O bond plays an important role, as it is a partner in the rigid unit mode motion and the order-disorder transition mechanism. |
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