Hydrothermal Synthesis of Negative Thermal Expansion Material ZrW_(1.7)Mo_(0.3)O_8 Powder

The negative thermal expansion material cubic phase ZrW1.7Mo0.3O8 powder was synthesized by using zirconium oxynitric, ammonium tungstate and ammonium molydbate as raw materials. X-ray powder diffraction (XRD), thermogravimetric analysis (TG-DSC), Fourier transform infrared spectroscopy (FT-IR), scanning electron micrograph (SEM) were used to study the crytallization process of the precursor, crystallinity and crystal morphology of the resulted product. The results show that pure cubic ZrW1.7Mo0.3O8 are prepared, and the particle size distribution is relatively uniform. In the temperature range from ambient temperature to 700℃, the intrinsic and macro thermal expansion coefficients of cubic ZrW1.7Mo0.3O8 are -6.61×10-6K-1 and -5.76×10-6K-1 respectively.