Abstract: Near zero expansion oxide functional ceramics Zr_0.5Hf_0.5V_1.4P_0.6O₇ was synthesized by the traditional solid-state method and then the thermal expansion properties of the synthesized samples were explored.X-ray diffraction(XRD), Raman spectra and thermal dilatometry were used to investigate the coefficient of thermal expansion (CTE), isotropy and phase transition of Zr_0.5Hf_0.5V_1.4P_0.6O₇.Hf⁴⁺/P⁵⁺ double ion doping results in the material has smaller coefficient of thermal expansion. The investigation results show that the samples are single cubic phase with the space group of Pa3 in the crystal structure. The linear expansion coefficient of Zr_0.5Hf_0.5V_1.4P_0.6O₇ is calculated to be -1.56×10^-6 K^-1 in the temperature range from 334 K to 673 K and has near-zero thermal expansion characteristic in a wide temperature range. Due to the influence of the internal microstructure of the solid solution, there is a certain gap between the expansion test results and the X-ray diffraction results at variable temperature. The near zero thermal expansion (NZTE) property of Zr_0.5Hf_0.5V_1.4P_0.6O₇ provides a basis for the synthesis of materials with controllable expansion coefficient of negative thermal expansion materials.

Key words: near zero thermal expansion, Zr_0.5Hf_0.5V_1.4P_0.6O₇, phase transition, coefficient of thermal expansion, isotropy, solid-state method, Raman spectrum