Tailoring of thermal expansion and phase transition temperature of ZrW2O8 with phosphorus and enhancement of negative thermal expansion of ZrW1.5P0.5O7.75

ZrW2O8 is a typical isotropic negative thermal expansion material with cubic structure.However,quenching prepa-ration,pressure phase transition and metastable structure influence its practical applications.Adopting P to part-substitute W for ZrW2-xPxO8-0.5x has decreased the sintering temperature and avoided the quenching process.When x=0.1,ZrW1.9P0.1O7.95 with a stable cubic structure can be obtained at 1150℃.The thermal expansion coefficient is tailored with the P content,and phase transition temperature is lowered.When x=0.5,thermal expansion coefficient attains-13.6×10-6℃-1,ZrW1.5P0.5O7.75 exhibits enhance negative thermal expansion property.The difference of electroneg-ativity leads to the decrease of phase transition temperature with the increase of P content.The different radii of ions lead to new structure of materials when P substitutes more.The results suggest that the P atom plays the stabilization role in the crystal structure of ZrW2-xPxO8-0.5x.