Synthesis and property study on negative thermal expansion ZrW2O8 powders using the citric acid sol-gel method

Negative thermal expansion (NTE) material ZrW2O8 powders were synthesized by the sol-gel method with citric acid used as chelating agent. The precursor of ZrW2O8 was studied by thermogravimetric and differential scanning calorimetry (TG-DSC). The structure and morphology of the resulting powders were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The results showed that the samples were single phase of α-ZrW2O8 with irregular shape. With the increasing amount of citric acid, the particles grew bigger with a slice layer shape. The High temperature X-ray diffraction measurement indicated that the material had strong NTE. From room temperature to 500, the average thermal expansion coefficient was -6.14×10-6/. ©, 2015, Journal of Functional Materials. All right reserved.