Investigation On The Properties Of V_1-xM_xO₂（M=Zn,Mg）Via Hydrothermal Method

In this paper, pure VO₂ nanoparticles and Zn doped Mg doped nanoparticles were synthetized via hydrothermal process. The structure and properties of VO₂ nanoparticles were characterized by X ray diffraction, scanning electron microscopy, Raman scattering,differential scanning electron microscopy, and the mechanical were discussed.（1） VO₂ nanoparticles were synthetized by useing oxalic acid and vanadium pentoxide via hydrothermal process, and annealed at 450℃,500℃,550℃ and 600℃ respectively.The result of XRD, DSC ant test of temperature resistance shows that higher anneal temperature is in favor of the VO₂ transformation from B phase to R phase. And we can obtain the best performance of VO₂ after it annealed at 600℃.（2） VO₂ nanoparticles with different Zn doping ratio were synthetized by useing oxalic acid, vanadium pentoxide and zinc nitrate via hydrothermal process and annealed at 580℃.The XRD test results shows that when the concentration of Zn doping is low, no influence on crystal structure, but when the concentration of Zn increased to 4at.%, same impurity phase Zn2V2O7 appeared. The SEM test shows that Zn doped VO₂ has no influence on surface morphology. Raman scattering indaicate that with the concentration of Zn doping increased, the M2 phase during the process of phase transformation decreased gradually and finaly disappeared. DSC test showed that Zn doping can decrease the MIT temperature of VO₂, but no linear relationship with the decreased MIT temperature. The resistance test showed that Zn doping can increase resistance mutation, when the doping ratio of Zn is 4at.%, the resistance mutation reached 104.（3） VO₂ nanoparticles with different Mg doping ratio were synthetized by useing oxalic acid, vanadium pentoxide and magnesium acetate via hydrothermal process and annealed at 580 ℃. The XRD test indicates that Mg doped in VO₂, it influenced the M phase microstructure. The SEM shows that Mg doped in VO₂ has no influenc on the morphology of the nanoparticles. Raman test shows that with the concentration of Mg doping increased,the M2 phase during the process of phase transformation decreased at frist and then increased, Mg doping is more complex than Zn doping in the influence of VO₂ phase transition process. DSC show that the VO₂ phase transition temperature decreased about3℃ each dopant 2at.% Mg.