用X射线衍射强度测定纳米金刚石的德拜特征温度和熔点

 采用陆学善、梁敬魁提出的方法，利用纳米金刚石的X射线衍射强度，计算出它的德拜特征温度为411.7 K，比高温高压合成出的大颗粒金刚石单晶的德拜特征温度（2 200 K）低了许多；且其原子晶格振动的振幅比高温高压合成得到的大颗粒金刚石单晶原子的振幅增大了4.37倍；用Lindemann公式计算出纳米金刚石的熔点为2 070 K，约为高温高压合成出的大颗粒金刚石单晶熔点（4 400 K）的一半。这将导致纳米金刚石原子间结合力的减弱，势必造成其活性的增大，从而引起物理、化学性能的改变。

The Determination of Melting-Point and Debye Characteristic Temperature of Nano-Diamond from X-Ray Diffraction Intensities

The melting-point of nano-diamond was reported in this paper.The Debye characteristic temperature of nano-diamond was calculated based on X-ray diffraction intensities by the methods introduced by LU Xue-Shan and LIANG Jing-Kui.Its Debye characteristic temperature is 411.7 K,which is about one-fifth of the Debye characteristic temperature of bulk diamond single crystal synthesized under high temperature and high-pressure condition.The melting point of nano-diamond is 2070 K calculated with Lindemann's formula.The atom vibration amplitude,which deflected balance position, increases two times or more.This leads to the increasing of activity of nano-diamond.