Rapid synthesis and Raman spectroscopic study of the negative thermal expansion material of A (WO4)2 (A = Zr2+, Hf2+)

The crystal structure of ZrW2O8 and HfW2O8 displays unusual property of isotropic negative thermal expansion in a wide temperature range, which brings about a number of important potential applications. In this work, densely packed A (WO4)2 (A = Zr2+, Hf2+) are rapid synthesized by CO2 laser. The result of XRD and Raman spectra show that the ZrW2O8 is γ phase with space group P212121 and HfW2O8 is α phase with space group P213. Due to the influence of compressive stress, laser rapid solidification technique is more suitable for industrial production of HfW2O8.