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采用球环法研究了用大功率ＤＣＰｌａｓｍａＪｅｔＣＶＤ沉积的无衬底自支撑金刚石厚膜的断裂强度和断裂韧度，并试图探索其与原始显微组织特征（特别是晶粒度）的关系。发现ＣＶＤ金刚石膜的强度和断裂韧度均远低于天然Ⅱａ型宝石级金刚石单晶。对于未抛光的试样，数据的离散程度掩盖了任何可能存在的规律性，而对于经过抛光的试样，研究结果表明与众所周知的ＰｅｔｃｈＨａｌ公式有相当好的吻合，说明细化晶粒仍然是提高ＣＶＤ金刚石膜力学性能的有效途径。预先存在的内部裂纹是ＣＶＤ金刚石膜强度低的重要原因之一。
The ball loop method was used to study the fracture strength and fracture toughness of a diamond free substrate with DCPlasmaJetCVD deposited by high power. The relationship between the fracture toughness and the original microstructure, especially the grain size, was explored. It is found that the strength and fracture toughness of CVD diamond films are far lower than the natural type IIa gem diamond single crystal. For unpolished specimens, the data dispersion obscures any possible regularity, whereas for the polished specimens, the results show a good agreement with the well-known Petch-Hal formula, indicating that refined grains are still Is to improve the mechanical properties of CVD diamond film an effective way. Pre-existing internal cracks are one of the important reasons for the low strength of CVD diamond films.