用溶胶-凝胶法制备了不同粒度的锐钛矿 TiO_2纳米粉末。当热处理温度不大于520℃时,可以得到稳定的单相锐钛矿结构。用 X 射线衍射方法测量了不同粒度的德拜温度和点阵参数的变化。实验发现,点阵参数和德拜温度的平方都与粒度的倒数成正比,这可能是纳米晶粒的表面张力作用引起的。 Anatase TiO_2 nanopowders with different particle sizes were prepared by sol-gel method. When the heat treatment temperature is not more than 520 ℃, we can get a stable single-phase anatase structure. The changes of Debye temperature and lattice parameters with different grain sizes were measured by X-ray diffraction. The experimental results show that the square of lattice parameters and Debye temperature are proportional to the reciprocal of grain size, which may be caused by the surface tension of nanocrystalline grains.