中文摘要：

研究了自支撑今刚石膜的生长取向特征、表面形貌和质量对断裂强度的影响。X射线衍射和断裂强度的结果表明,随着衍射强度比值I（111）/I（220）的增大,断裂强度呈下降趋势。堆积在晶粒间界处的二次形核生长的小晶粒,覆盖晶粒间界的缝隙,在柱状晶粒间形成类似的搭桥效应,增强柱状晶之间的相互作用能,提高柱状晶结构的抗破断能力,金刚石膜中出现的非金刚石相将降低金刚石厚膜的断裂强度。

英文摘要：

Free-standing diamond films were synthesized by 100 kW DC arc plasma jet chemical vapor deposition using a CH4/Ar/H2 gas mixture. The effect of growth characteristics on fracture strength of the free-standing diamond films was investigated. The deposited films were characterized by scanning electron microscopy, Raman spectroscopy and X-ray diffraction. The fracture strength of diamond films was tested by three point bending method. The results show that the fracture strength decreases with I（111）II（220） increasing. The pileup of small grains by second nucleation among columnar grain covers grain boundaries and forms ＂joining bridge＂, and thus the fracture strength of free-standing diamond films is increased, however, non-diamond phase in the free-standing diamond films decreases its fracture strength.