Effect of PVP on Morphology and Property of Negative Thermal Expansion ZrW₂O₈ Powders by Sol-gel Method

Abstract

ZrW2O8 powders were prepared by sol-gel method with PVP as the additive. The effect of PVP on the morphology was studied and negative thermal expansion property of ZrW2O8 powders was also investigated. The precursor of ZrW2O8 was analysized by thermogravimetric and differential scanning calorimetry (TG-DSC). The structure and morphology of the resulting powder were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The results show that the resulting powder is single cubic α-ZrW2O8 phase. The addition of PVP can effectively change the morphology of the powder, with the increasing amount of PVP, morphology of the particles changes from irregular aggregates to rod-like, fan-shaped and short rod particles. The results of in-situ X-ray diffraction measurement indicate that ZrW2O8 powder prepared with the addition of PVP has good negative thermal expansion property.

Keywords

• negative thermal expansion
• sol-gel method
• PVP
• ZrW₂O₈