Abstract：Negative thermal expansion （NTE） ZrW2O8 powder and ceramic were synthesized by solidstate reaction using analytically pure ZrO2 and WO3. The microstructures and section morphologies of the products were characterized by X -ray diffraction （XRD） and scanning electron microscope （SEM） re- spectively. The NTE coefficients of the samples were measured by three different methods. The effects of testing method on NTE coefficients were investigated. The results indicate that the resulting product is cubic ZrW2O8. The average thermal expansion coefficient of cubic ZrW2O8 is - 5. 605 × 10^-6 K-1 from room temperature to 600℃ obtained by high temperature X - ray diffraction measurement and Power X software ; and that of sintering ZrW2O8 ceramic rod is - 10. 709 × 10^-6 K^-1 and pressing ZrW2O8 powder rod is -4. 490 × 10^-6 K^-1, obtained by thermal dilatometer. The measuring method, density and microstructure all have effects on the measurement of NTE coefficient of the samples.
2009, Vol. 30 
