Effects of heat treatment conditions and Y-doping on structure and phase transition temperature of VO2 powders
(1. School of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China;
2. Research Center of Metallurgical Engineering and Technology of Shaanxi Province, Xi’an 710055, China)
2. Research Center of Metallurgical Engineering and Technology of Shaanxi Province, Xi’an 710055, China)
Abstract: The VO2 powders were prepared by hydrothermal synthesis. The effects of heat treatment conditions and Y-doping on the structure and phase transition temperature of VO2 were studied. The XRD, SEM and TEM results show that the heat treatment temperature has a significant effect on the crystal transformation of VO2 precursor. Increasing temperature is conducive to the transformation of precursor VO2(B) to ultrafine VO2(M). The Y-doping affects the structure of VO2. Y3+ can occupy the lattice position of V4+ to form YVO4 solid solution, which can increase the cell parameters of VO2. Due to the lattice deformation caused by Y-doping, the aggregation of particles is prevented, and the grain is refined obviously. DSC curves show that Y-doping can reduce the phase transition temperature of VO2(M). After adding 9 at.% Y, the phase transition temperature can be reduced from 68.3 to 61.3 °C.
Key words: VO2 powders; hydrothermal synthesis; heat treatment; Y-doping; phase transition temperature