热处理条件对VO_2粉体晶体结构和相变性能的影响

以V2O5和草酸为原料,采用高温热解前驱体法制备VO2粉体,并结合XRD分析和热致相变性能测定,研究热处理条件对VO2粉体晶体结构和相变性能的影响。结果表明,采用三段式升温制度,可制备晶化程度较高的VO2粉体。制备过程中,热分解温度的升高或热分解时间的延长,均会导致产物VO2粉体平均晶粒尺寸增大、平均晶格畸变率降低、相变滞豫区间减小以及电阻突变量增大,热处理过程中VO2晶粒生长和晶格畸变率变化主要受热分解温度的控制。

Effect of thermal treatment conditions on the crystal structure and phase transition characteristics of VO2 powders

VO₂ powders were prepared from V₂O₅ and oxalic acid by the pyrolysis precursor method,and effects of different thermal treatment conditions on the crystal structure and phase transition characteristics were studied by XRD and thermochromic property determination.The results show that VO₂ powders with higher crystallization degree can be prepared by employing 3-step heating schedule. Either with the increase of thermal decomposition temperature or the extending of decomposition time, the grain size of VO₂ powders increases, crystal lattice distortion rate decreases, hysteresis width decreases and adrupt drop of resistance rises. Thermal decomposition temperature is the major factor that affects the grain size and the lattice distortion rate of VO₂ powders.